We discovered, that phosphazenyl phosphines (abbreviated“PAP”) such as P(N=PR ₃ )3 can be stronger P-superbases than their corresponding Schwesinger type phosphazene N-superbases tBuN=P(N=PR ₃ ) ₃ . A simple synthetic access to this class of PR ₃ derivatives (R = N-phosphazenyl radical) including their homologization is described. XRD structures, proton affinities (PA) and gas phase basicities (GB) as well as calculated and experimental pK _BH ⁺ values in THF are presented. In contrast to their N-basic counterparts, PAPs are also privileged ligands in transition metal chemistry. In fact, they are the strongest uncharged P-donor ligands known so far, exceeding classical and more recently discovered P-superdonors such as PtBu ₃ or imidazolin-2-ylidenamino phosphines IAPs with respect to their low Tolman electronic parameter TEP and large cone angles. During the past two decades uncharged organic superbases became a veritable tool in organic synthesis. Marking the high end record of the solvent dependent pK _BH ⁺ scale Schwesinger’s famous phosphazene N-superbases became commercially available and subject of many investigations and applications in organic synthesis and catalysis. In previous studies we demonstrated, that N-superbasicity of a diphosphazene could dramatically be increased by placing a second diphosphazene N-donor in close proximity within a rigid spacer unit. Such bidentate chelating bisdiphosphazene proton-sponges or proton-pincers display a pK _BH ⁺ up to sixteen orders of magnitude higher than their non- chelating monodentate counter parts. Homologization concept was utilized to achieve a similar trend for other uncharged nitrogen superbases such as guanidines, cyclopropene- imines, and combinations of them as well as their bidentate proton sponge derivatives. A similar molecular superbase design has been investigated by theory and experiment for uncharged carbon bases such as related phosphorus ylides and their bisylide pincers. Compared to the dominating class of N-bases, phosphorus(III) compounds were not systematically considered as extremely strong proton-acceptors so far within the state of the art. The main field of interest and application lies in creating very strong donors (i. e. electron donors, superbases) in transition metal chemistry and catalysis. Verkade’s proazaphosphatranes are early representatives of rare superbasic phosphines. Schmutzler et al. attempted to synthetize a potentially very basic tris(tetramethylguanidino)phosphine. They were able to isolate the P-protonated form, but deprotonation leads to disintegration of this PR3 derivative. In 2016 Dielmann et al. solved the problem of guanidine degradation by using related aromatically stabilized imidazolin- 2-ylidenamino N-substituents to access the very interesting class of electron rich IAP ligands with their high basicity as well as outstanding Tolman electronic parameters TEP and large cone angles.

Here we report that Schwesinger’s phosphazene bases, the up to date strongest uncharged proton acceptors, surprisingly become even more basic, if formally the nitrene tBuN unit at the terminal P(V) imine is reductively eliminated. This allows access to a class of corresponding P(III) superbases, the phosphazenyl phosphines PAPs. In contrast to phosphazenes, these PAPs are privileged to form a wide range of transition metal coordination compounds as well, thus complementing the class of IAP ligand complexes. Here, we demonstrate, that PAPs are indeed the most electron rich uncharged PR ₃ donors known so far, exceeding even IAPs with respect to their higher pK _BH + and lower TEP values. A convenient synthesis for PAPs and an abbreviation related to Schwesinger’s phosphazenes is introduced:“(R ₂ N)P ^V

xP ^III ” denotes a P(III) base incorporating x phosphazenyl units. R ₂ N represents secondary amino substituents at the P(V) phosphazene skeleton, typically dimethylamino (dma) and pyrrolidyl (pyrr) groups, however other members of this family with alkyl groups etc. can be derived as well.

The title compounds are readily prepared by reaction of– for example - electrophiles (Me ₂ N) ₂ PCl (1a) or (Et ₂ N) ₂ PCl (1b) with– for example– built-in auxiliary base and phosphazenes (R ₂ N) ₃ P=NH (5) (Scheme 1). In contrast to the classical Kirsanov reaction applying PCl ₃ and excess of nucleophile as auxiliary base, the inventive PAP target compounds are therefore formed in good yields and not in a mixture of ammonium and phosphonium salts difficult to separate. The very simple preparation of the desired product, resulting thereof, is also a benefit of the inventive process. As PAP hydrochlorides turned out to be hygroscopic, a precipitation step with NaBF ₄ from aqueous solution leads to crystalline airstable and indefinitely storable P-H functional phosphonium salts [PAP-H]BF4. In an early attempt to prepare the pure base ((Me ₂ N) ₃ P=N) ₃ P from its hydrochloride, Kirsanov et al. exchanged chloride for hydroxide (via moist Ag2O). Vacuum dehydration of [((R ₂ N)3P=N)3PH]OH led to a viscous liquid of unknown composition, in part probably a hydrate of the base. The basicity of this species was never established experimentally but theoretically. We surprisingly discovered, that deprotonation of our class of salts [PAP-H]BF4 and higher homologues by KHMDS (or comparable metal amides) in toluene or THF leads to colorless solids as pure P(III) Brønsted and Lewis superbases. With this strategy the protonated forms of the symmetric (dma)P ₃ P (2∙HBF ₄ ) and (pyrr)P ₃ P (3∙HBF ₄ ) were isolated in excellent yields as exemplary products (compounds) of the inventive process. Furthermore it was possible to employ Schwesinger’s homologization concept on corresponding phosphines and to synthesize the higher homologue (dma)P ₆ P∙HBF ₄ (4∙HBF ₄ ).

Scheme 1. Preparation of P3P and P6P phosphonium salts: a) (dma)3P=NH (5a) and 1a or 1b in THF, 3h 60 °C, 87%; b) (pyrr) ₃ P=NH (5b) and 1a or 1b in toluene, 3h 90 °C, 96%; c) (dma) ₃ P=N-P(dma) ₂ =NH (6) and 1a in THF, 72 h reflux, 83%. Work-up by precipitation from aqueous NaBF4 described exemplarily in the experimental section.

For (dma)P ₄ P∙HBF ₄ (7∙HBF ₄ ) having one bisphosphazenyl and two monophosphazenyl substituents the standard procedure had to be varied as shown in Scheme 2. The mixed valent P(III)/P(V) precursor (dma)P ₁ P (8) turned out to be an adequate starting material as it does not react with the phosphazenes (6 or 5a), but only with their protonated form (5a∙HBF ₄ or 6∙HBF ₄ ) to the corresponding phosphonium salt, which selectively reacts only with the added phosphazene to 7∙HBF ₄ , no matter which building block is used as free phosphazene or protonated form.

Scheme 2. Preparation of 7∙HBF ₄ : 8 and 5a∙HBF ₄ or 6∙HBF ₄ in THF, 1 h 60 °C, then 6 or 5a respectively, 1 h 60 °C, 94%. Work-up described exemplarily in the experimental section . Protonated PAPs in the ³¹ P NMR spectra show doublets between 21.5 and 15.3 ppm for terminal P(dma)3 groups or at 7.9 ppm for P(pyrr)3 groups, respectively. The bridging P(V) atoms in 7∙HBF ₄ and 4∙HBF ₄ show a double doublet at 2.2 or 0.1 ppm. The P(III) atom in all compounds exhibits a quartet around -30 ppm, which splits without ¹ H-BB decoupling to a double quartet with a ¹ JPH coupling constant of ~550 Hz. The phosphorus bonded proton exhibits a signal in shape of a double quartet between 7.89 and 7.58 ppm in the ¹ H NMR spectra. Figure 1 shows exemplarily the molecular structures of the phosphonium cations with the acidic protons always located at the central phosphorus atom. The formal P-N single bonds are with average bond length of 1.57 Å even slightly shorter than formal P=N double bonds (1.60 Å) and reveal a strong influence of negative hyperconjugation. The N-P=N angle is widened up between 129.0 and 157.7°. Dimethylamino groups have P-N distances of 1.646 Å for terminal phosphazenyl groups, and 1.670 Å in bridging phosphazenyl groups. Pyrrrolidine substituents are bonded with an average distance of 1.640 Å. Upon deprotonation the ³¹ P NMR signals show a strong downfield shift to ~80 ppm for the signal of the P(III) atoms, whilst the P(V) signal gets slightly upfield shifted and the ² JPP coupling constants becomes smaller. So far, we did not yet isolate the free base form of (dma)P6P (4), but could generate it in situ in a suspension of large excess freshly ground NaNH ₂ in THF or potassium pyrrolidid in toluene. Deprotonation under the action of organolithium bases lead to side reactions whereas potassium in liquid ammonia or ethylendiamine showed no reactivity due to lack of proton activity. The existence of this probably strongest of all uncharged metal free bases 4 could however be proven by a combination of ³¹ P NMR spectroscopy and consecutive reactions as well as by calculations. Similar to Schwesinger’s P7-tBu phosphazene counterpart isolation of an analytically pure sample of the base form (dma)P ₆ P remains a challenge for future work.

The electron donor capability of PAPs was quantified by pK _BH ⁺ values (Table 1), the Tolman electronic parameter (TEP) and the ¹ JPSe coupling (Table 2). Evaluation of NMR titration experiments of the phosphonium salts against Schwesinger’s (dma)P4-tBu (pK _BH + in THF: 33.9) or (pyrr)P ₄ -tBu (35.3) as reference bases revealed the highest pK _BH ⁺ values known so far for any phosphines. More importantly, the basicity of phosphines 2 and 3 exceeds the basicity of their corresponding reference phosphazenes by 0.9 and 1.4 units, respectively. Therefore, although superbase 4 was not isolated, we could determine its basicity with high accuracy. It appears that pK _BH ⁺ (THF) of 4 surpass that of (dma)P ₄ -tBu by 7.1 units. Inspection of data reveals that phosphines 2 and 3 possess higher pK _BH + (THF) values than corresponding phosphazenes, whereas 7 and 4 are slightly less basic in comparison with related phosphazenes. The origin of higher pK _BH ⁺ values of the former is their higher intrinsic (gas phase) basicity, whereas solvation effects work into the opposite direction– protonated phosphazenes are better solvated in THF than protonated phosphines. Slightly higher basicity of (dma)P ₅ -tBu and (dma)P ₇ -tBu phosphazenes in the gas phase and in THF could be attributed to a presence of weak intramolecular hydrogen bonds (IHB) in conjugate acids that does not exist in (dma)P4-tBu and (pyrr)P4- tBu, neither in any of studied phosphines. However, influence of IHB weakens in solvents of higher dielectric constants such as acetonitrile, therefore in this solvent all studied phosphines are stronger bases than related phosphazenes.

Small proton self-exchange rates are indicated by high coalescence temperatures of 1:1 mixtures of PAP bases and their acid forms in NMR solvents. These low rates are probably due to small polarization of the P-H bond compared to N-H. Barriers for the intermolecular proton exchange are 15.5 kcal∙mol ^-1 for 2 and 16.5 kcal∙mol ^-1 for 3, which complies with an exchange rate of 13 Hz and 3 Hz respectively (all at 293 K) and are therefore more in the region of proton sponges of high kinetic basicity rather than of their phosphazene counterparts. Table 1. Experimental pK _BH ⁺ values in THF.

pKBH ⁺ (THF) experimental (dma)P3P 34.9 ^[b,c] (pyrr)P3P 36.7 ^[c] (dma)P4P 37.2 ^[c] (dma)P ₆ P - P(NIiPr) ₃ 31.0

Verkade base 24.1 (dma)P4-tBu 33.9 (pyrr)P ₄ -tBu 35.3 [b] ³¹ P NMR titration against (dma)P4-tBu. [c] ³¹ P NMR titration against (pyrr)P4-tBu.

Corresponding phosphine selenides 9-12 were obtained by oxidation of PAPs with grey selenium, [(PAP)Ni(CO)3] complexes 13-16 by reaction with [Ni(CO)4] (Scheme 3).

Scheme 3. Preparation of phosphine selenides 9-12 and nickel carbonyl complexes 13- 16.

A much more distinctness of formal P-N single and double bonds, compared to protonated PAPs, was found in the XRD molecular structures of representative PAP complexes of nickel (15) and platinum (17) (Figure 4) as well as the selenide 10 (displayed in the experimental section) with average formal P=N and P-N bonds of 1.543 Å and 1.624 Å, respectively. The ¹ JPSe coupling constants are in accordance with the trend in PAP basicity: We observe drastically lower coupling compared to prominently basic phosphorus selenides. Most interestingly, the TEP values of PAPs are considerably lower than those of known IAPs. Therefore the strongest uncharged electron donating PR3 ligands known so far are revealed herein. These phosphazenylphosphines (“PAP”) can be advantageously used as extremely basic organic uncharged catalysts and/or as ligands in metal complexes. The metal complexes can be used as catalysts for numerous chemical reactions where metal and / or base-catalysis is applied. For example, the Au ^I -PAP-complexes are very effective catalysts for the Au(I)-catalyzed hydroamination of alkynes with amines or Pd(0)- catalyzed CC-cross-coupling reactions. PAP-platinum(0) complexes highly efficiently catalyze olefin hydrosilylation reactions. Also, polymerization reactions, e.g. the anionic polymerization of methyacrylate MMA to PMMA can be catalyzed very efficiently by PAP even in the absence of metals and in the presence or absence of alcohols. Many more examples of using PAPs as superdonor ligands in catalysts or as proton acceptor catalysts are envisaged. PAPs combine steric and electronic properties that are highly valuable for the design of extremely electron-rich transition-metal bases such as platinum complexes 17 and 18 (Scheme 4). The extreme reducing power of PAPs leads to reductive elimination of chlorine and substitution of PPh3 at [(Ph3P)2PtCl2] to form linear 14 valence electron bisphosphine complexes 17 and 18.

Table 2. TEP values and ¹ J _PSe couplings of selenides.

TEP /cm ^{-1[a] 1} JPSe/Hz ^[c] (dma)P3P 2022.4 654 (pyrr)P3P 2018.6 628 (dma)P ₄ P 2017.3 631 (dma)P6P 2014.5 ^[c] 608 ^[c] P(NIiPr)3 2029.7 - Verkade

2057.0 754

base PtBu3 2056.1 687 [a] Determined via ATR-IR spectroscopy of neat substance. [c] ¹ J _PSe couplings determined in this work via ³¹ P and ⁷⁷ Se NMR spectroscopy in C ₆ D ₆ at room temperature. [c] Reaction of 4∙HBF ₄ , NaNH ₂ and Ni(CO)4 or Segray respectively, no pure compound isolated.

XRD data of 17 reveal that the Pt-P bond to sterically less demanding PPh3 ligand (2.213 Å) is shorter than that to PAP (2.312 Å) indicating the importance of PPh ₃ p- backbonding contrasting the extreme PAP s^donation in such heteroleptic model complexes. The assumption of an almost pure and strong PAP-Pt s-bond is in compliance with results from ³¹ P and ¹⁹⁵ Pt NMR spectroscopy: The ¹ J _PPt Pt-PPh ₃ coupling constant of 3236 Hz is only about half as large as the one of Pt-PAP (6153 Hz). So far this seems to be one of the largest ¹ JPPt reported in Pt-PR3 literature. The ¹⁹⁵ Pt NMR shift of 17 (– 6238 ppm) is in the range of homoleptic [Pt(PtBu ₃ )] (d _Pt = -6471 ppm, ¹ J _PPt = 4420 Hz, Pt-P 2.249 Å). This indicates that the much stronger electron donating PAP is compensating the better p-backbonding PPh ₃ ligand in the overall shielding.

Scheme 4. Preparation of Pt(0) complexes 17 and 18: With [(Ph3P)2Pt(C ₂ H4)] and PAP in a 1:1 ratio in toluene, 3 h 90 °C; with [(Ph ₃ P) ₂ PtCl ₂ ] in a 1:2 ratio in toluene, 3 h, 90 °C. In summary, we presented a sophisticated synthesis, the homologization strategy and structural characterization of a class of phosphazenyl phosphines PAPs. Very surprisingly such uncharged P(III) superbases are more basic than corresponding phosphazenyl phosphazenes (Schwesinger bases), so far the champions for strongest uncharged bases. Ranking in their kinetic and thermodynamic basicity seems to be depending on differences in P-H and N-H bond polarity and solvation effects. They are stronger donor ligands towards transition metals than any other known PR ₃ ligand class, consequently they reveal the lowest Tolman electronic parameter TEP of all PR3 ligands. These findings are based on experimental pKBH ⁺ (THF) values, on experimental NMR and IR data, finally on XRD structures of exemplarily synthesized PAP adducts with representative transition metals, with the non-metal selenium and the simplest electrophile of all, the proton.

Experimental section

Synthetic Details General Remarks All reactions with air or moisture sensitive substances were carried out under inert atmosphere using standard Schlenk techniques. Air or moisture sensitive substances were stored in a nitrogen-flushed glovebox. Solvents were purified according to common literature procedures and stored under an inert atmosphere over molsieve (3 Å or 4 Å). Pyrrolidine was distilled from CaH ₂ . Potassium bis(trimethylsilyl)amide, benzyl potassium, (h ² -ethylene)bis(triphenylphosphane)platinum(0),

bis(dimethylamino)phosphorus chloride (1a), tris(dimethylamino)phosphazene (5a), tris(pyrrolidino)phosphazene (5b) and (pyrr)P ₄ -tBu were prepared according to literature-known procedures. (dma)P ₄ -tBu was purchased as 1M solution in n-hexan and dried in high vacuum. All other reagents were used as provided. ¹ H, ¹³ C, ³¹ P and ⁷⁷ Se NMR spectra were recorded on a Bruker Avance III HD 250, Avance II 300, Avance III HD 300 or Avance III HD 500 spectrometer. Chemical shift d is denoted relatively to SiMe4 ( ¹ H, ¹³ C), 85% H3PO4 ( ³¹ P), SeMe2 ( ⁷⁷ Se) or K2PtCl6 ( ¹⁹⁵ Pt). ¹ H and ¹³ C NMR spectra were referenced to the solvent signals, ¹⁹⁵ Pt NMR spectra externally to K2PtCl4 (0.5M in D2O, d = -1617.5 ppm). Multiplicity is abbreviated as follows: s (singlet), d (doublet), t (triplet), q (quartet), m (multiplet), br. (broad signal). High resolution mass spectrometry were performed on a Thermo Fisher Scientific LTQ- FT Ultra or a Jeol AccuTOF GCv., elemental analysis on an Elementar Vario Micro Cube. IR spectra were recorded in a glovebox on a Bruker Alpha ATR-FT-IR.

General procedure for the precipitation of tetrafluoridoborate and tetraphenylborate salts from aqueous solution: The crude product was dissolved in a minimum amount of water and a solution of a 10% excess of the respective sodium WCA salt in a minimal amount of water was added under stirring. The precipitate was filtered or centrifuged off, rinsed with cold water and dried in high vacuum. The compounds can be reprecipitated from THF/diethyl ether.

General procedure for the preparation of phosphane containing solutions: A mixture of the respective phosphonium tetrafluoridoborate and a 10% excess of base, e.g. potassium bis(trimethylsilyl)amide, was stirred for 90 min in toluene, centrifuged and the supernatant clear solution used for consecutive reactions.

Amino[tris(dimethylamino)phosphazenyl]bis(dimethylamino)p hosphonium bromide (6∙HBr): The compound was synthesized as BF ₄ ^– salt from the respective phosphine oxide before. Here we present a preparation via

[tris(dimethylamino)]bis(dimethylamino)phosphine (8):

8 (32.87 g, 111 mmol, 1.00 eq) was dissolved in 250 mL THF and cooled to 0 °C. Bromine (5.70 mL, 111 mmol, 1.00 eq) was added dropwise and after warming to room temperature ammonia was passed into the mixture. Precipitated ammonium bromide was filtered off and extracted with dichloromethane. The combined filtrate was evaporated and n-pentane was added to the residue. The supernatant solution was decanted and the solid dried in vacuo to isolate 6∙HBr (36.94 g, 94 mmol, 85%) as colorless solid. Consecutive deprotonation to 6 was conducted as is known by the person skilled in the art (cf., for example, the method of Schwesinger.

[C10H32BrN7P2] (392.27 g∙mol ^-1 ) ¹ H-NMR (300.2 MHz, CDCl ₃ ): d (ppm) = 4.24 (br. d, ² J _PH = 4 Hz, 2H, NH ₂ ) 2.70 (d, ² J _PH = 11 Hz, 12H, H2), 2.68 (d, ² J _PH = 10.4 Hz, 18H, H1). ¹³ C{ ¹ H}-NMR (75.5 MHz, CDCl ₃ ): d (ppm) = 37.2 (d, ² JPC = 5 Hz, C2), 37.2 (d, ² JPC = 5 Hz, C1). ³¹ P{ ¹ H}-NMR (121.5 MHz, CDCl ₃ ): d (ppm) = 21.2 (d, ² JPP = 59 Hz, P1), 16.6 (d, ² J _PP = 59 Hz, P2). ESI(+)-MS (MeOH): m/z (%) = 312.41 (100) [M-Br] ⁺ . ESI(+)- HRMS: m/z [M-Br] ⁺ calcd.312.2184, found 312.2189. Elemental analysis: calcd. C 30.62%, H 8.22%, N 25.00%; found C 30.77%, H 8.32%, N 25.22%. Tris[tris(dimethylamino)phosphazenyl]phosphonium tetrafluoridoborate (dma)P ₃ P∙HBF ₄ (2∙HBF ₄ ):

The preparation of the hydrochloride 2∙HCl from phosphorus trichloride was described by Kirsanov et al.

1a (326 mg, 2.11 mmol, 1.00 eq), dissolved in THF (10 mL), was added to a solution of 5a (1.15 g, 6.45 mmol, 3.06 eq) in THF (30 mL). After stirring for 1 h at room temperature the mixture was heated for 3 h at 60 °C. All volatile components were removed in vacuo and the residue washed with diethyl ether (3x 40 mL). After drying in high vacuum the hygroscopic 2∙HCl was converted to its tetrafluoridoborate salt as described in the general procedure to afford 2∙HBF ₄ (1.196 g, 1.84 mmol, 87%) as colorless solid.

[C18H55BF4N12P4] (650.42 g∙mol ^-1 ) ¹ H-NMR (500.2 MHz, C ₆ D ₆ ): d (ppm) = 7.65 (dq, ¹ JPH = 554 Hz, ³ J _PH = 5 Hz, 1H, PH), 2.49 (d, ³ J _PH = 10 Hz, 54H, N(CH ₃ ) ₂ ). ¹³ C{ ¹ H}-NMR (125.8 MHz, C ₆ D ₆ ): d (ppm) = 37.1 (d, ² JPC = 4 Hz). ³¹ P{ ¹ H}-NMR (202.5 MHz, C ₆ D ₆ ): d (ppm) = 21.5 (d, ² JPP = 30 Hz, P(dma) ₃ ), -28.9 (q, ² JPP = 31 Hz, PH). ³¹ P-NMR

(202.5 MHz, C ₆ D ₆ ): d (ppm) = 21.5 (br. m, P(dma) ₃ ), -28.9 (dq, ¹ JPH = 554 Hz, ² JPP = 31 Hz, PH). ESI(+)-MS (MeOH): m/z (%) = 563.7 (100) [M-BF ₄ ] ⁺ . ESI(+)-HRMS: m/z [M-BF4] ⁺ calcd.563.3618, found 563.3628. Elemental analysis: calcd. C 33.24%, H 8.52%, N 25.84%; found C 32.90%, H 8.52%, N 25.49%. IR (neat):ṽ (cm ^-1 ) = 2883 (m, CH ₃ ), 2848 (m, CH ₃ ), 2803 (m, CH ₃ ), 2300 (w, PH), 1457 (m), 1289 (m), 1230 (s), 1179 (s), 1094 (m), 1050 (s), 969 (vs), 854 (m), 832 (m), 766 (m), 740 (s), 642 (m), 612 (m), 500 (s). XRD: For single crystal X-ray structure determination BPh ₄ - was used instead of BF4-. Suitable single crystals were obtained by slowly cooling a concentrated solution in methanol/water.

Tris[tris(pyrrolidino)phosphazenyl]phosphonium tetrafluoridoborate (pyrr)P ₃ P∙HBF ₄ (3∙HBF ₄ )

vacuum the hygroscopic 3∙HCl was converted to its

tetrafluoridoborate salt as described in the general procedure to afford 3∙HBF4 (4.839 g, 5.47 mmol, 96%) as colorless solid.

[C ₃₆ H ₇₃ BF ₄ N ₁₂ P ₄ ] (884.76 g∙mol ^-1 ) ¹ H-NMR (300.2 MHz, C ₆ D ₆ ): d (ppm) =7.89 (dq, ¹ J _PH = 556 Hz, ³ JPH = 4 Hz, 1H, PH), 3.21-3.17 (m, 36H, H1), 1.77-1.73 (m, 36H, H2).

1 ³ C{ ¹ H}-NMR (75.5 MHz, C ₆ D ₆ ): d (ppm) = 47.2 (d, ² J _PC = 5 Hz, C1), 26.9 (d, ³ J _PC = 8 Hz, C2). ³¹ P{ ¹ H}-NMR (101.3 MHz, C ₆ D ₆ ): d (ppm) = 7.9 (d, ² JPP = 24 Hz, P(pyrr) ₃ ), -29.3 (q, ² JPP = 23 Hz, PH). ³¹ P-NMR (101.3 MHz, C ₆ D ₆ ): d (ppm) = 7.9 (br. d, ² JPP = 24 Hz, P(pyrr) ₃ ), -29.3 (dq, ¹ JPH = 555 Hz, ² JPP = 23 Hz, PH). ESI(+)-MS (MeOH): m/z (%) = 798.0 (100) [M-BF ₄ ] ⁺ . ESI(+)-HRMS: m/z [M-BF ₄ ] ⁺ calcd.797.5026, found 797.5030. Elemental analysis: calcd. C 48.87%, H 8.32%, N 19.00%; found C 48.68%, H 8.36%, N 18.95%. IR (neat):ṽ(cm ^-1 ) = 2949 (m, CH ₂ ), 2853 (m, CH ₂ ), 2292 (w, PH), 1448 (w), 1345 (w), 1313 (w), 1223 (m), 1202 (s), 1125 (s), 1079 (s), 1046 (s), 994 (s), 912 (m), 866 (m), 813 (m), 765 (m), 701 (w), 587(s), 560 (s), 501 (s). XRD: For single crystal X-ray structure determination BPh ₄ - was used instead of BF ₄ -. Suitable single crystals were obtained by dissolving in toluene and layering with diethyl ether.

[Pentakis(dimethylamino)diphosphazenyl]bis[tris(dimethyla mino)phosphazenyl]- phosphonium tetrafluoridoborate (dma)P4P∙HBF4 (7∙HBF ₄ )

8 (1.519 g, 5.12 mmol, 1.17 eq) was added to a suspension of 5a∙HBF ₄ (1.165 g, 4.38 mmol, 1.00 eq) in THF (60 mL) and stirred for 1 h at 60 °C. After cooling to room temperature 6 (1.364 g, 4.38 mmol, 1.00 eq) was added and the mixture was stirred for one additional hour at 60 °C. All volatile components were removed in vacuo and the resulting oil was diluted with n-hexane (40 mL) to precipitate the product, which was washed after decantation of the supernatant solvent with more n-hexane (2x 40 mL). Drying in high vacuum afforded 7∙HBF ₄ (3.230 g, 4.122 mmol, 94%) as colorless solid.

[C ₂ 2H67BF4N15P5] (783.56 g∙mol ^-1 ) ¹ H-NMR (500.1 MHz, C ₆ D ₆ ): d (ppm) = 7.60 (ddt, ¹ JPH = 549 Hz, ³ JPH = 6 Hz, ³ JPH = 2 Hz, 1H, PH), 2.57 (d, ³ JPH = 11 Hz, 12H, H3), 2.54 (d, ³ J _PH = 10 Hz, 18H, H2), 2.53 (d, ³ J _PH = 10 Hz, 36H, H1). ¹³ C{ ¹ H}-NMR (125.8 MHz, C ₆ D ₆ ): d (ppm) = 37.6 (d, ² JPC = 4 Hz, C3), 37.2 (d, ² JPC = 5 Hz, C1), 31.1 (d, ² JPC = 5 Hz, C2). ³¹ P{ ¹ H}-NMR (101.3 MHz, C ₆ D ₆ ): d (ppm) = 19.9 (d, ² JPP = 27 Hz, P1), 16.6 (d, ² JPP = 54 Hz, P2), 2.2 (dd, ² JPP = 54 Hz, ² JPP = 27 Hz, P3), -28.8 (dt, 2x ² JPP = 27 Hz, PH). ³¹ P-NMR (101.3 MHz, C ₆ D ₆ ): d (ppm) = 19.9 (br. m, P1), 16.6 (br. m, P2), 2.2 (br. m, P3), -28.8 (ddt, ¹ JPH = 549 Hz, 2x ² JPP = 27 Hz, PH). ESI(+)-MS (MeOH): m/z (%) = 696.6 (100) [M-BF ₄ ] ⁺ . ESI(+)-HRMS: m/z [M-BF ₄ ] ⁺ calcd.696.4386, found 696.4402. Elemental analysis: calcd. C 33.72%, H 8.62%, N 26.81%; found C 33.64%, H 8.26%, N 26.81%. IR (neat):ṽ (cm ^-1 ) = 2996 (w, CH ₃ ), 2885 (br. m, CH ₃ ), 2848 (m, CH ₃ ), 2807 (w, CH ₃ ), 2316 (w, PH), 1455 (w), 1361 (w), 1269 (s), 1232 (s), 1181 (s), 1093 (m), 1049 (s), 1035 (sh. s), 966 (vs), 860 (m), 808 (w), 794 (w), 736 (s), 642 (m), 591 (w), 499 (s), 480 (m), 447 (m). XRD: For single crystal X-ray structure determination suitable single crystals were obtained by dissolving in toluene and layering with n- hexane. Tris[pentakis(dimethylamino)diphosphazenyl]phosphonium tetrafluoridoborate

(dma)P6P∙HBF4 (4∙HBF ₄ )

1a (329 mg, 2.13 mmol, 1.00 eq), dissolved in 5 mL THF, was added to a solution of 6 (2.00 g, 6.43 mmol, 3.01 eq) in THF (20 mL). After stirring for 1 h at room temperature a reflux condenser with a bubbler was mounted and the clear reaction mixture was heated for 72 h under reflux conditions. All volatile components were removed in vacuo, n-hexane (40 mL) was added to the residue to precipitate the product as colorless solid and separate it from the supernatant solvent by decantation. After washing with n-hexane (2x 20 mL) and drying in high vacuum the hygroscopic 4∙HCl was converted to its

tetrafluoridoborate salt as described in the general procedure to afford 4∙HBF ₄ (1.858 g, 1.77 mmol, 83%) as colorless solid.

[C ₃ 0H91BF4N21P7] (1049.83 g∙mol ^-1 ) ¹ H-NMR (300.2 MHz, C ₆ D ₆ ): d (ppm) = 7.58 (dq, ¹ JPH = 540 Hz, ³ JPH = 5 Hz, 1H, PH), 2.67 (d, ³ JPH = 11 Hz, 36H, H2), 2.57 (d, ³ JPH = 10 Hz, 54H, H1). ¹³ C{ ¹ H}-NMR (75.5 MHz, C ₆ D ₆ ): d (ppm) = 38.0 (d, ² JPC = 4 Hz, C2), 37.1 (d, ² J _PC = 5 Hz, C1). ³¹ P{ ¹ H}-NMR (101.3 MHz, C ₆ D ₆ ): d (ppm) = 15.3 (d, ² J _PP = 54 Hz, P1), 0.1 (dd, ² JPP = 54 Hz, ² JPP = 23 Hz, P2), -30.6 (q, ² JPP = 24 Hz, PH). ³¹ P- NMR (101.3 MHz, C ₆ D ₆ ): d (ppm) = 15.3 (br. m, P1), 0.1 (br. m, P2), -30.6 (dq, ¹ J _PH = 540 Hz, ² J _PP = 24 Hz, PH). ESI(+)-MS (MeOH): m/z (%) = 962.8 (100) [M-BF ₄ ] ⁺ .

ESI(+)-HRMS: m/z [M-BF4] ⁺ calcd.962.5924, found 962.5926. Elemental analysis: calcd. C 34.32%, H 8.74%, N 28.02%; found C 34.22%, H 8.65%, N 28.03%. IR (neat): ṽ (cm ^-1 ) = 2874 (br. m, CH ₃ ), 2796 (m, CH ₃ ), 2308 (w, PH), 1456 (m), 1271 (s), 1230 (s), 1178 (s), 1093 (m), 1049 (s), 963 (vs), 857 (s), 786 (m), 736 (m), 641 (s), 586 (m), 507 (s), 479 (s). XRD: For single crystal X-ray structure determination suitable crystals were obtained by slowly evaporating a concentrated solution in diethyl ether.

Tris[tris(dimethylamino)phosphazenyl]phosphine (dma)P3P (2)

In an early attempt to prepare the free base from its hydrochloride, Kirsanov et al.

exchanged chloride for hydroxide (via moist Ag ₂ O). Vacuum dehydration of [(dma)P ₃ P- H]OH _aq led to a viscous liquid. A solution of potassium bis(trimethylsilyl)amide (403 mg,

2.02 mmol, 1.00 eq) in toluene (20 mL) was added slowly to a solution of 2∙HBF ₄ (1.314 g, 2.02 mmol, 1.00 eq) and stirred for 30 min at room temperature. Precipitated potassium

tetrafluoridoborate was centrifuged off and all volatiles of the clear solution were removed in vacuo. The resulting oil was dissolved in n-pentane (30 mL) and filtered over celite. Evaporation of the solvent and drying in high vacuum yielded 2 (985 mg, 1.75 mmol, 87%) as colorless solid.

[C ₁₈ H ₅₄ N ₁₂ P ₄ ] (562.61 g∙mol ^-1 ) ¹ H-NMR (500.2 MHz, C ₆ D ₆ ): d (ppm) = 2.74 (d, ³ J _PH = 10 Hz, 54H). ¹³ C{ ¹ H}-NMR (125.8 MHz, C ₆ D ₆ ): d (ppm) = 38.2 (dd, ² JPC = 3 Hz, ⁴ JPC = 3 Hz). ³¹ P{ ¹ H}-NMR (202.5 MHz, C ₆ D ₆ ): d (ppm) = 83.4 (q, ² JPP = 19 Hz, P ^III ), 14.4 (d, 2J _PP = 21 Hz, P(dma) ₃ ). LIFDI(+)-MS (toluene): m/z (%) = 562.4 (20) [M] ⁺ , 563.4 (100) [M+H] ⁺ . LIFDI(+)-HRMS: m/z [M] ⁺ calcd.562.35448, found 562.35234. Elemental analysis: calcd. C 38.43%, H 9.67%, N 29.88%; found C 38.33%, H 9.83%, N 30.15%. IR (neat):ṽ (cm ^-1 ) = 2991 (w, CH ₃ ), 2865 (m, CH ₃ ), 2831 (m, CH ₃ ), 2788 (m, CH ₃ ), 1453 (m), 1282 (m), 1166 (vs), 1064 (m), 990 (sh. s), 959, (vs), 765 (m), 720 (vs), 609 (m), 572 (s), 518, (w), 481 (m), 442 (m), 414 (w).

Tris[tris(pyrrolidino)phosphazenyl]phosphine (pyrr)P ₃ P (3)

A solution of potassium bis(trimethylsilyl)amide (341 mg, 1.71 mmol, 1.00 eq) in toluene (20 mL) was added slowly to a solution of 3∙HBF ₄ (1.510 g, 1.71 mmol, 1.00 eq) in toluene (30 mL) and stirred for 90 min at room temperature.

Precipitated potassium tetrafluoridoborate was centrifuged off and all volatile components of the clear solution were removed in vacuo. The residue was dissolved in n-pentane (20 mL), filtered over celite and the filter cake extracted with n-pentane (20 mL). The solvent was evaporated and the resulting oil dried in high vacuum until crystallization set in.3

(1.202 g, 1.51 mmol, 88%) was isolated as colourless solid.

[C ₃ 6H72N12P4] (796.95 g∙mol ^-1 ) ¹ H-NMR (500.1 MHz, C ₆ D ₆ ): d (ppm) =3.45-3.41 (m, 36H, H1), 1.78-1.73 (m, 36H, H2). ¹³ C{ ¹ H}-NMR (125.8 MHz, C ₆ D ₆ ): d (ppm) = 47.4 (dd, 2J _PC = 4 Hz, ⁴ J _PC = 4 Hz C1), 26.9 (d, ³ J _PC = 8 Hz, C2). ³¹ P{ ¹ H}-NMR (202.5 MHz, C ₆ D ₆ ): d (ppm) = 81.1 (q, ² J _PP = 10 Hz, P ^III ), 1.35 (d, ² J _PP = 12 Hz, P(pyrr) ₃ ). ³¹ P-NMR (202.5 MHz, C ₆ D ₆ ): d (ppm) = 81.1 (q, ² JPP = 10 Hz, P ^III ), 1.35 (br. s, P(pyrr) ₃ ). LIFDI(+)- MS (THF): m/z (%) = 796.5 (34) [M] ⁺ , 797.5 (100) [M+H] ⁺ . LIFDI(+)-HRMS: m/z [M] ⁺ calcd.796.49533, found 796.49287. Elemental analysis: calcd. C 54.26%, H 9.11%, N 21.09%; found C 53.55%, H 9.14%, N 20.92%. IR (neat):ṽ (cm ^-1 ) = 2953 (m, CH ₂ ), 2843 (m, CH ₂ ), 1456 (w), 1342 (w), 1290 (w), 1179 (s), 1129 (vs), 1059 (vs), 995 (s), 911 (m), 872 (m), 809 (w), 756 (s), 690 (m), 562 (s), 477 (s), 424 (m).

[Pentakis(dimethylamino)diphosphazenyl]bis[tris(dimethyla mino)phosphazenyl]- phosphine (dma)P ₄ P (7)

A solution of potassium bis(trimethylsilyl)amide (275 mg, 1.38 mmol, 1.01 eq) in 20 mL toluene was added slowly to a solution of 7∙HBF ₄ (1.070 g, 1.37 mmol, 1.00 eq) in 30 mL toluene. The yellow suspension was stirred at 90 C for 3 h and centrifuged after cooling to room temperature. All volatiles of the clear solution were removed in vacuo, the residue dissolved in 25 mL n-hexane and filtered over celite. The filtrate was evaporated and dried in high vacuum to obtain 7 (752 mg, 1.08 mmol, 79%) as pale yellow oil. [C ₂ 2H66N15P5] (695.74 g∙mol ^-1 ) ¹ H-NMR (500.2 MHz, C ₆ D ₆ ): d (ppm) = 2.99 (d, ³ JPH = 11 Hz, 12H, H3), 2.79 (d, ³ J _PH = 10 Hz, 36H, H1), 2.66 (d, ³ J _PH = 10 Hz, 18H, H2).

1 ³ C{ ¹ H}-NMR (125.8 MHz, C ₆ D ₆ ): d (ppm) = 39.0 (dd, JPC = 5 Hz, JPC =4 Hz, C3), 38.4 (dd, 2x JPC = 4 Hz, C1), 37.7 (dd, JPC = 4 Hz, JPC =3 Hz, C2). ³¹ P{ ¹ H}-NMR (202.5 MHz, C ₆ D ₆ ): d (ppm) = 84.7 (dt, ² J _PP = 48 Hz, ² J _PP = 18 Hz, P ^III ), 19.4 (d, ² J _PP = 43 Hz, P2), 11.2 (d, ² J _PP = 18 Hz, P1), 1.0 (dd, 2x ² J _PP = 46 Hz, P3). ³¹ P-NMR (202.5 MHz, C ₆ D ₆ ): d (ppm) = 84.7 (dt, ² JPP = 48 Hz, ² JPP = 18 Hz, P ^III ), 19.7-19.1 (m, P2), 11.2 (br. s, P1), 1.0 (br. s, P3). LIFDI(+)-MS (THF): m/z (%) = 695.4 (100) [M] ⁺ . LIFDI(+)-HRMS: m/z [M] ⁺ calcd.695.43137, found 695.43108. IR (neat):ṽ (cm ^-1 ) = 2991 (w, CH ₃ ), 2867 (sh. m, CH ₃ ), 2834 (s, CH ₃ ), 2788 (s, CH ₃ ), 1455 (m), 1281 (s), 1165 (vs), 1065 (m), 959 (vs), 810 (w), 719 (vs), 635 (m), 622 (m), 568 (s), 485 (s).

General procedure for the preparation of nickeltricarbonyl complexes 9-11: The nickeltricarbonyl complexes of 2, 3 and 4 were prepared as follows: A solution of the respective phosphine in toluene (5 mL) was added to a solution of tetracarbonylnickel in toluene (5 mL) at 0 °C. The mixture was warmed to room temperature, all volatiles were removed in vacuo, the residue dissolved in n-pentane (20 mL) and cleared via syringe filtration. Evaporation of the solvent and drying in high vacuum gave the respective nickeltricarbonyl complexes as colourless to pale yellow solids.

[Tricarbonyl{tris[tris(dimethylamino)phosphazenyl]phosphi ne}nickel(0)] (9)

2 (103 mg, 183 µmol, 1 eq) and tetracarbonylnickel (0.03 mL, 0.2 mmol, 1 eq) gave 9 (72 mg, 0.10 mmol, 56%) as pale yellow solid.

[C ₂₁ H ₅₄ N ₁₂ NiO ₃ P ₄ ] (705.33 g∙mol ^-1 ) ¹ H-NMR (500.2 MHz, C ₆ D ₆ ): d (ppm) = 2.64 (d, ³ JPH = 10 Hz, 54H). ¹³ C{ ¹ H}-NMR (125.8 MHz, C ₆ D ₆ ): d (ppm) = 203.4 (d, ² JPC = 9 Hz, CO), 37.8 (d, ² JPC = 4 Hz, N(CH ₃ ) ₂ ). ³¹ P{ ¹ H}- NMR (202.5 MHz, C ₆ D ₆ ): d (ppm) = 53.2 (q, ² J _PP = 18 Hz, PNi), 3.1 (d, ² J _PP = 18 Hz, P(dma) ₃ ). LIFDI(+)-MS (toluene): m/z (%) = 704.3 (100) [M] ⁺ . LIFDI(+)-HRMS: m/z [M] ⁺ calcd.704.27458, found 704.27597. Elemental analysis: calcd. C 35.76%, H 7.72%, N 23.83%; found C 36.96%, H 7.72%, N 24.06%. IR (neat):ṽ (cm ^-1 ) = 2997 (w, CH ₃ ), 2871 (sh. m, CH ₃ ), 2836 (m, CH ₃ ), 2793 (m, CH ₃ ), 2022 (m, CO), 1929 (vs, CO), 1480 (w), 1454 (m), 1409 (w), 1244 (s), 1190 (s), 1065 (m), 967 (vs), 775 (m), 722 (s), 572 (s), 486 (s), 471 (s), 444 (m).

[Tricarbonyl{tris[tris(pyrrolidino)phosphazenyl]phosphine }nickel(0)] (10)

3 (144 mg, 181 µmol, 1.0 eq) and tetracarbonylnickel (0.10 mL, 0.44 mmol, 2.4 eq) gave 10 as colourless solid. [C ₃₉ H ₇₂ N ₁₂ NiO ₃ P ₄ ] (939.67 g∙mol ^-1 ) ¹ H-NMR (300.2 MHz, C ₆ D ₆ ): d (ppm) = 3.37-3.31 (m, 36H, H1), 1.75-1.71 (m, 36H, H2). ¹³ C{ ¹ H}-NMR (75.5 MHz, C ₆ D ₆ ): d (ppm) = 203.9 (d, ² J _PC = 9 Hz, CO), 47.0 (d, ² J _PC = 5 Hz, C1), 26.8 (d, ³ J _PC = 9 Hz, C2). ³¹ P{ ¹ H}-NMR (101.3 MHz, C ₆ D ₆ ): d (ppm) = 51.0 (q, ² JPP = 21 Hz, PNi), -11.6 (d, 2JPP = 21 Hz, P(pyrr) ₃ ). LIFDI(+)-MS (toluene): m/z (%) = 797.5 (50) [M+H-Ni(CO)3] ⁺ , 938.4 (100) [M] ⁺ . LIFDI(+)-HRMS: m/z [M] ⁺ calcd.938.41543, found 938.41557. IR (neat):ṽ (cm ^-1 ) = 2959 (m, CH ₂ ), 2861 (m, CH ₂ ), 2019 (m, CO), 1928 (vs, CO), 1902 (sh. w), 1458 (w), 1305 (m), 1290 (m), 1227 (vs), 1196 (s), 1130 (s), 1074 (vs), 1007 (vs), 913 (w), 870 (w), 765 (w), 740 (w), 707 (w), 676 (w), 577 (s), 558 (s), 517 (w), 472 (s).

[Tricarbonyl{[pentakis(dimethylamino)diphosphazenyl]bis[t ris(dimethylamino)- phosphazenyl]phosphine}nickel(0)] (11)

7 (138 mg, 198 µmol, 1 eq) and tetracarbonylnickel

(0.03 ml, 0.2 mmol, 1 eq) gave 11 (148 mg, 177 µmol, 89%) as colourless crystalline solid.

[C ₂₅ H ₆₆ N ₁₅ NiO ₃ P ₅ ] (838.47 g∙mol ^-1 ) ¹ H-NMR (300.2 MHz, C ₆ D ₆ ): d (ppm) = 2.88 (d, ³ J _PH = 11 Hz, 12H, H3), 2.71 (d, ³ JPH = 10 Hz, 36H, H1), 2.51 (d, ³ JPH = 10 Hz, 18H, H2). ¹³ C{ ¹ H}-NMR (75.5 MHz, C ₆ D ₆ ): d (ppm) = 204.0 (d, ² J _PC = 9 Hz, CO), 38.8 (d, ² J _PC = 4 Hz, C3), 37.9 (d, ² J _PC = 4 Hz, C1), 37.5 (d, ² JPC = 4 Hz, C2). ³¹ P{ ¹ H}-NMR (101.3 MHz, C ₆ D ₆ ): d (ppm) = 48.6 (d, ² JPP = 69 Hz, PNi), 12.3 (d, ² JPP = 52 Hz, P2), 1.24 (s, P1), -10.3 (dd, ² JPP = 68 Hz, ² JPP = 52 Hz, P3). LIFDI(+)-MS (benzene): m/z (%) = 696.4 (100) [M+H-Ni(CO)3], 837.4 (29) [M] ⁺ . LIFDI(+)-HRMS: m/z [M] ⁺ calcd.837.35146, found 837.35139. Elemental analysis: calcd. C 35.81%, H 7.93%, N 25.06%; found C 35.34%, H 7.98%, N 24.73%. IR (neat):ṽ (cm ^-1 ) = 3003 (w, CH ₃ ), 2872 (m, CH ₃ ), 2833 (m) CH ₃ ), 2793 (m, CH ₃ ), 2017 (m, CO), 1927 (vs, CO), 1898 (sh. w), 1482 (m), 1454 (m), 1285 (s), 1180 (vs), 1062 (m), 962 (vs), 820 (w), 770 (s), 723 (s), 705 (s), 624 (m), 582 (m), 564 (m), 525 (m), 493 (s), 467 (s), 438 (sh. m). XRD: The isolated product was suitable for single crystal X-ray structure determination.

Tris[tris(dimethylamino)phosphazenyl]phosphine selenide (13)

A solution of potassium bis(trimethylsilyl)amide (40 mg,

0.20 mmol, 1.0 eq) in toluene (5 mL) was added to a solution of 2∙HBF ₄ (126 mg, 194 µmol, 1.0 eq) in toluene (5 mL). After stirring for 1 h at room temperature, gray selenium (16 mg, 0.20 mmol, 1.0 eq) was added and stirred for 1 h at 90 °C. After cooling to room temperature the mixture was centrifuged, the supernatant clear solution separated and all volatiles were removed in vacuo. The residue was dissolved in n-pentane (10 mL) and cleared via syringe filtration. Removal of the solvent and drying in high vacuum gave 13 as pale yellow solid.

[C18H54N12P4Se] (642.27 g∙mol ^-1 ) ¹ H-NMR (300.2 MHz, C ₆ D ₆ ): d (ppm) = 2.79 (d, ³ JPH = 10 Hz, 54H). ¹³ C{ ¹ H}-NMR (125.8 MHz, C ₆ D ₆ ): d (ppm) = 38.1 (d, ² JPC = 4 Hz). ³¹ P{ ¹ H}- NMR (121.5 MHz, C ₆ D ₆ ): d (ppm) = 13.0 (d, ² J _PP = 35 Hz, P(dma) ₃ ), -6.7 (q, ² J _PP = 35 Hz, ¹ JPSe = 645 Hz (satellites), PSe). ⁷⁷ Se{ ¹ H}-NMR (95.4 MHz, C ₆ D ₆ ): d (ppm) = 137.9 (d, ¹ JPSe = 645 Hz). LIFDI(+)-MS (toluene): m/z (%) = 642.3 (100) [M] ⁺ . LIFDI(+)- HRMS: m/z [M] ⁺ calcd.642.27108, found 642.26810. Elemental analysis: calcd. C 33.70%, H 8.48%, N 26.20%; found C 34.09%, H 8.46%, N 25.66%.

Tris[tris(pyrrolidino)phosphazenyl]phosphine selenide (14)

A solution of potassium bis(trimethylsilyl)amide (34 mg, 0.17 mmol, 1.3 eq) in toluene (10 mL) was added to a solution of 3∙HBF ₄ (114 mg, 129 µmol, 1.0 eq) in toluene (10 mL) and stirred for 1 h at room temperature. Gray selenium (18 mg, 0.23 mmol, 1.8 eq) was added and the mixture stirred at room temperature overnight. The brown mixture was centrifuged and all volatiles of the clear yellow solution were removed in vacuo. The residue was dissolved in n-pentane (20 mL) and cleared via syringe filtration. The solvent was evaporated slowly and colourless crystalline 14 dried in high vacuum.

[C ₃₆ H ₇₂ N ₁₂ P ₄ Se] (875.91 g∙mol ^-1 ) ¹ H-NMR (500.2 MHz, C ₆ D ₆ ): d (ppm) = 3.52-3.48 (m, 36H, H1), 1.83-1.80 (m 36H, H2). ¹³ C{ ¹ H}-NMR (125.8 MHz, C ₆ D ₆ ): d (ppm) = 47.3 (d, ² JPC = 4 Hz, C2), 26.9 (d, ³ JPC = 9 Hz, C2). ³¹ P{ ¹ H}-NMR (202.5 MHz, C ₆ D ₆ ): d (ppm) = 0.6 (d, ² J _PP = 22 Hz, P(pyrr) ₃ ), -5.5 (q, ² J _PP = 22 Hz, ¹ J _PSe = 628 Hz (satellites), PSe). ⁷⁷ Se{ ¹ H}-NMR (95.4 MHz, C ₆ D ₆ ): d (ppm) = 190.9 (d, ¹ J _PSe = 628 Hz). LIFDI(+)-MS (toluene): m/z (%) = 876.4 (100) [M] ⁺ . LIFDI(+)-HRMS: m/z [M] ⁺ calcd.876.41216, found 876.41236. Elemental analysis: calcd. C 49.37%, H 8.29%, N 19.19%; found C 49.30%, H 8.38%, N 18.47%. XRD: The isolated product was suitable for single crystal X-ray structure determination. [Pentakis(dimethylamino)diphosphazenyl]bis[tris(dimethylamin o)phosphazenyl]- phosphine selenide (15)

Toluene (20 mL) was added to a mixture of 7∙HBF ₄ (170 mg, 217 µmol, 1.0 eq) and potassium bis(trimethylsilyl)amide (44 mg, 0.22 mmol, 1.0 eq) and the mixture was stirred for 1 h at room temperature and 1 h at 90 °C. Gray selenium (19 mg, 0.24 mmol, 1.1 eq) was added and stirred for one additional hour at 90 °C. The solid was centrifuged off and all volatiles of the solution were removed in vacuo. The residue was dissolved in n-pentane (10 mL), cleared via syringe filtration and dried in high vacuum.15 was obtained as pale yellow solid.

[C ₂ 2H66N15P5Se] (775.35 g∙mol ^-1 ) ¹ H-NMR (300.2 MHz, C ₆ D ₆ ): d (ppm) = 2.98 (d, ³ JPH = 11 Hz, 12H, H3), 2.83 (d, ³ JPH = 10 Hz, 36H, H1), 2.65 (d, ³ JPH = 10 Hz, 18H, H2).

1 ³ C{ ¹ H}-NMR (75.5 MHz, C ₆ D ₆ ): d (ppm) = 38.9 (d, ² J _PC = 4 Hz, C3), 38.2 (d, ² J _PC = 4 Hz, C1), 37.6 (d, ² JPC = 4 Hz, C2). ³¹ P{ ¹ H}-NMR (121.5 MHz, C ₆ D ₆ ): d (ppm) = 19.0 (d, ² JPP = 44 Hz, P2), 11.2 (d, ² JPP = 42 Hz, P1), -6.9 (dd, ² JPP = 44 Hz, ² JPP = 12 Hz, P3), -13.1 (dt, ² JPP = 42 Hz, ² JPP = 12 Hz, ¹ JPSe = 631 Hz (satellites), PSe). ⁷⁷ Se{ ¹ H}- NMR (57.3 MHz, C ₆ D ₆ ): d (ppm) = 127.6 (d, ¹ J _PSe = 631 Hz). LIFDI(+)-MS (benzene): m/z (%) = 775.3 (100) [M] ⁺ . LIFDI(+)-HRMS: m/z [M] ⁺ calcd.775.34801, found

775.34666.

[{Tris[tris(dimethylamino)phosphazenyl]phosphine}(triphen ylphosphine)platinum(0)] (17)

Toluene (10 mL) was added to a mixture of 2∙HBF ₄ (173 mg, 265 µmol, 1.0 eq) and potassium bis(trimethylsilyl)amide (58 mg, 0.29 mmol, 1.1 eq) and stirred for 90 min at room temperature. Precipitated potassium tetrafluoridoborate was separated by centrifugation and the supernatant added to a solution of (h ² -

ethylene)bis(triphenylphosphane)platinum(0) (204 mg, 273 µmol, 1.0 eq) in toluene (5 mL) and stirred over weekend at room temperature. All volatiles were removed in vacuo, the residue dissolved in n-pentane (10 mL) and filtered. The filtrate was stored at–25 °C, the resulting crystals separated by decantation, washed with cold n-pentane (4 mL) and dried in high vacuum to isolate 17 as yellow crystals containing one equivalent n-pentane as cocrystallizate.

[C ₃ 6H69N12P5Pt] (1019.98 g∙mol ^-1 ) ¹ H-NMR (300.3 MHz, THF-d8): d (ppm) = 7.72-7.66 (m, 6H, m-H), 7.21-7.18 (m, 9H, o,p-H), 2.76 (d, ³ JPH = 10 Hz, 54H, CH ₃ ). ¹³ C{ ¹ H}-NMR (125.8 MHz, C ₆ D ₆ ): d (ppm) = 140.2 (d, ¹ J _PC = 37 Hz, i-C), 134.9 (d, ³ J _PC = 13 Hz, m-C), 128.3 (overlapped with the solvent signal, p-C), 127.6 (d, ² JPC = 9 Hz, o-C), 38.3 (d, ² JPC = 3 Hz, CH ₃ ). ³¹ P{ ¹ H}-NMR (121.5 MHz, THF-d8): d (ppm) = 87.8 (dq, ² JPP = 549 Hz, 2J _PP = 26 Hz, ¹ J _PPt = 6147 Hz (satellites), N ₃ PPt), 47.1 (d, ² J _PP = 549 Hz, ¹ J _PPt = 3229 Hz (satellites), Ph ₃ PPt), 12.3 (d, ² J _PP = 26 Hz, P(dma) ₃ ). ¹⁹⁵ Pt{ ¹ H}-NMR (64.54 MHz, THF- d8): d (ppm) =

–6238 (dd, ¹ JPPt = 6153 Hz, ¹ JPPt = 3236 Hz). LIFDI(+)-MS (n-hexane): m/z (%) = 1019.4 (100) [M] ⁺ . LIFDI(+)-HRMS: m/z [M] ⁺ calcd.1019.41039, found 1019.41330. XRD: The isolated crystalline product was suitable for single crystal X-ray structure determination.

[{Tris[tris(pyrrolidino)phosphazenyl]phosphine}(triphenyl phosphine)platinum(0)] (18)

Toluene (15 mL) was added to a mixture of 3∙HBF ₄ (242 mg, 274 µmol, 1.0 eq) and potassium bis(trimethylsilyl)amide (60 mg, 0.30 mmol, 1.1 eq) and stirred for 90 min at room temperature. Precipitated potassium tetrafluoridoborate was separated by centrifugation and the supernatant added to a solution of (h ² -ethylene)bis(triphenylphosphane)platinum(0)

(204 mg, 273 µmol, 1.0 eq) in toluene (5 mL) and stirred for 3 h at 90 °C. All volatiles were removed in vacuo, the residue dissolved in n-hexane (20 mL) and filtered. The filtrate was stored at–35 °C, the resulting crystals separated by decantation, washed with cold n-pentane (2 mL) and dried in high vacuum to isolate 18 as yellow crystals. [C ₅ 4H87N12P5Pt] (1254.33 g∙mol ^-1 ) ¹ H-NMR (300.3 MHz, THF-d8): d (ppm) = 7.70-7.64 (m, 6H, m-H), 7.19-7.17 (m, 9H, o,p-H), 3.41-3.35 (m, 36H, H1), 1.72-1.64 (m, 36H, H2). ¹³ C{ ¹ H}-NMR (75.7 MHz, C ₆ D ₆ ): d (ppm) = 140.8 (dd, ¹ JPC = 35 Hz, ³ JPC = 2 Hz, i- C), 135.0 (dd, ³ JPC = 14 Hz, ⁵ JPC = 2 Hz, m-C), 128.3 (d, ⁴ JPC = 1 Hz, p-C), 127.5 (d, 2JPC = 9 Hz, o-C), 47.7 (d, ² JPC = 4 Hz, C1), 27.0 (d, ³ JPC = 9 Hz, C2). ³¹ P{ ¹ H}-NMR (121.5 MHz, THF-d ₈ ): d (ppm) = 87.9 (dq, ² J _PP = 553 Hz, ² J _PP = 12 Hz, ¹ J _PPt = 6222 Hz (satellites), N3PPt), 45.9 (dd, ² JPP = 553 Hz, ⁴ JPP = 2 Hz, ¹ JPPt = 3185 Hz (satellites), Ph3PPt), -0.6 (dd, ² JPP = 12 Hz, ⁴ JPP = 1 Hz, P(dma) ₃ ). ¹⁹⁵ Pt{ ¹ H}-NMR (64.54 MHz, THF-d8): d (ppm) =–6219 (dd, ¹ JPPt = 6225 Hz, ¹ JPPt = 3183 Hz). LIFDI(+)-MS (n- hexane): m/z (%) = 1253.6 (100) [M] ⁺ . LIFDI(+)-HRMS: m/z [M] ⁺ calcd.1253.55124, found 1253.55229. Elemental analysis: calcd. C 51.71%, H 6.99%, N 13.40%; found C 51.84%, H 6.96%, N 13.78%.

Deprotonation attempts of (dma)P6P∙HBF4 (4∙HBF ₄ )

Several bases were testet for deprotonation of 4∙HBF ₄ , such as lithium di-iso- propylamid, potassium bis(trimethylsilyl)amide, potassium hydrid, benzyl potassium, elemental potassium and n- or t- butyllithium, which showed either no reaction or decomposition. Only excess of sodium amide in THF lead to a mixture of free 4 and 4∙HBF ₄ (Figure S1). Finally potassium pyrrolidid in toluene fully deprotonated the starting material (Figure S2) for consecutive reactions but isolation of the free base was not possible.

[Tricarbonyl{tris[pentakis(dimethylamino)diphosphazenyl]p hosphine}nickel(0)] (12)

4∙HBF ₄ (49 mg, 47 µmol, 1 eq) was dissolved in toluene (5 mL) and cooled to 0 °C. A solution of potassium pyrrolidid (5 mg, 0.05 mmol, 1 eq) in toluene (7 mL) was added slowly, the mixture allowed to warm to room temperature and added afterwards to a solution of tetracarbonylnickel (0.01 mL, 0.08 mmol, 1 eq) in toluene (8 mL). All volatiles were removed in vacuo the residue dissolved in n-pentane (10 mL) and and cleared via syringe filtration. The solvent was evaporated and the residue used for analytics. [C ₃ 3H90N21NiO3P7] (1104.74 g∙mol ^-1 ) ³¹ P{ ¹ H}-NMR (101.3 MHz, C ₆ D ₆ ): d (ppm) = 46.4 (q, ² JPP = 23 Hz, PNi), 7.4 (d, ² JPP = 56 Hz, P1), -13.9 (dd, ² JPP = 56 Hz, ² JPP = 23 Hz, P2). IR (neat):ṽ (cm ^-1 ) = 2015 (w, CO), 1926 (s, CO). Since no pure product could be isolated, the IR spectrum was calculated to ensure the correct bands were assigned.

# Tris[pentakis(dimethylamino)diphosphazenyl]phosphine selenide (16)

4∙HBF ₄ (49 mg, 47 µmol, 1 eq) was dissolved in toluene (5 mL) and cooled to 0 °C. A solution of potassium pyrrolidid (5 mg, 0.05 mmol, 1 eq) in toluene (7 mL) was added slowly, the mixture allowed to warm to room temperature and added afterwards to a suspension of gray selenium (4 mg, 0.05 mmol, 1 eq) in toluene (8 mL). The mixture was stirred at room temperature over night, all volatiles were removed in vacuo the residue dissolved in n-pentane (10 mL) and and cleared via syringe filtration. The solvent was evaporated and the residue dissolved in C ₆ D ₆ .

[C ₃ 0H90N21P7Se] (1040.97g∙mol ^-1 ) ³¹ P{ ¹ H}-NMR (202.5 MHz, C ₆ D ₆ ): d (ppm) = 12.1 (d, 2JPP = 54 Hz, P1), -9.7 (dd, ² JPP = 54 Hz, ² JPP = 21 Hz, P2), -17.6 (q, ² JPP = 21 Hz, 1J _PSe = 608 Hz (satellites), PSe). ⁷⁷ Se-NMR (95.4 MHz, C ₆ D ₆ ): d (ppm) = 120.4 (d, ¹ J _PSe = 609 Hz).LIFDI(+)-MS (C ₆ D ₆ ): m/z (%) = 978.6 (100) [M+O-Se], 1039.5 (27) [M] ⁺ .

LIFDI(+)-HRMS: m/z [M] ⁺ calcd.1039.50244, found 1039.50367.

[(Chlorido)cyclooctadien{tris[tris(dimethylamino)phosphaz enyl]phosphine}rhodium(I)]

A (dma)P3P containing solution (5 mL, 155 µmol, 2.0 eq), prepared according to the general procedure, was added to a solution of [(chlorido)(cyclooctadien)ruthenium(I)] dimer (39 mg, 79 µmol, 1.0 eq) in toluene (5 mL). All volatiles were removed in vacuo, the residue dissolved in n-pentane (15 mL) and cleared via syringe filter. Drying in high vacuum gave

[(chlorido)cyclooctadien{tris- [tris(dimethylamino)phosphazenyl]phosphane}rhodium(I)] as intense yellow solid.

[C ₂₆ H ₆₆ ClN ₁₂ RhP ₄ ] (809.15 g∙mol ^-1 ) ¹ H-NMR (500.1 MHz, C ₆ D ₆ ): d (ppm) = 5.56 (d, J = 3 Hz, 2H, CH), 3.91 (dd, J = 3 Hz, 2H, CH) 2.74 (d, ³ JPH = 10 Hz, 54H, N(CH ₃ ) ₂ ), 2.58- 2.53 (m, 2H, CH ₂ ), 2.42-2.35 (m, 2H, CH ₂ ), 2.14-2.03 (m, 4H, CH ₂ ). ¹³ C{ ¹ H}-NMR (125.8 MHz, C ₆ D ₆ ): d (ppm) = 99.5 (dd, ¹ J _RhC = 20 Hz, ² J _PC = 6 Hz, CH), 66.8 (d, ¹ J _RhC = 16 Hz, CH), 38.1 (d, ² JPC = 5 Hz, N(CH ₃ ) ₂ ), 34.0 (d, ² JRhC = 3 Hz, CH ₂ ), 29.4 (d, ² JRhC = 3 Hz, CH ₂ ). ³¹ P{ ¹ H}-NMR (202.5 MHz, C ₆ D ₆ ): d (ppm) = 26.1 (d, ¹ JPRh = 179 Hz, RhP), 3.7 (s, P(dma) ₃ ). LIFDI(+)-MS (toluene): m/z (%) = 773.3 (100) [M-Cl] ⁺ , 808.3 (20) [M] ⁺ . LIFDI(+)-HRMS: m/z [M] ⁺ calcd.808.32274, found 808.32282. Elemental analysis:

calcd. C 38.59%, H 8.22%, N 20.77%; found C 38.16%, H 8.06%, N 18.63%. XRD: For single crystal X-ray structure determination suitable single crystals were obtained by slowly cooling a concentrated solution in n-pentane.

[(Allyl)chlorido{tris[tris(pyrrolidino)phosphazenyl]phosp hane}palladium(II)]

A (dma)P ₃ P containing solution (5 mL, 155 µmol, 1.9 eq), prepared according to the general procedure, was added to a solution of [(allyl)(chlorido)palladium(II)] dimer (30 mg, 82 µmol, 1.0 eq) in toluene (5 mL). All volatiles were removed in vacuo, the residue dissolved in n-pentane (15 mL) and cleared via syringe filter. Drying in high vacuum gave

[(allyl)chlorido{tris[tris(pyrrolidino)phosphazenyl]phosp hane}-palladium(II)] as yellow crystalline solid, which turned out to be not stable in solution, wherefore no analytics other than ³¹ P NMR spectroscopy and XRD were possible.

[C ₂ 1H59ClN12PdP4] (745.55 g∙mol ^-1 ) ³¹ P{ ¹ H}-NMR (202.5 MHz, C ₆ D ₆ ): d (ppm) = 25.7 (q, ² J _PP = 3 Hz, PPd), 12.6 (br. s, P(dma) ₃ ). XRD: The obtained crystalline solid was suitable for single crystal X-ray structure determination.

[{Tris[tris(dimethylamino)-phosphazenyl]phosphane}(triphe nylphosphane)palladium(0)]

A (dma)P3P containing solution (14 mL, 129 µmol, 2.4 eq), prepared according to the general procedure, was added to a suspension of di-chloridobis(triphenylphosphane)palladium(II) (58.9 mg, 83.9 µmol, 1.0 eq) in toluene (5 mL) and stirred overnight at room temperature. The orange suspension was

centrifuged and the clear supernatant evaporated to dryness. The residue was dissolved in n-hexane (20 mL), filtered and the filtercake extracted again with n-hexane (2x 20 mL). The filtrate was reduced to a minimum and stored at–25 °C to isolate [{tris[tris(dimethylamino)- phosphazenyl]phosphane}(triphenylphosphane)palladium(0)] as orange crystals containing one equivalent n-pentane as cocrystallizate. [C ₃ 6H69N12P5Pd] (931.32 g∙mol ^-1 ) ¹ H-NMR (300.2 MHz, C ₆ D ₆ ): d (ppm) = 7.96-7.90 (m, 6H, m-H), 7.19-7.14 (m, 6H, o-H), 7.11-7.06 (m, 3H, p-H), 2.85 (d, ³ J _PH = 10 Hz, 54H, CH ₃ ). ¹³ C{ ¹ H}-NMR (75.5 MHz, C ₆ D ₆ ): d (ppm) = 140.9 (d, ¹ JPC = 23 Hz, i-C), 134.9 (d, ³ JPC = 17 Hz, m-C), 128.2 (overlapped with the solvent signal, p-C), 127.9 (d, ² JPC = 9 Hz, o-C), 38.3 (dd, J _PC = 4 Hz, J _PC = 2 Hz, CH ₃ ). ³¹ P{ ¹ H}-NMR (121.5 MHz, C ₆ D ₆ ): d (ppm) = 61.7 (dq, ² JPP = 401 Hz, ² JPP = 23 Hz, PdPN ₃ ), 26.5 (d, ² JPP = 400 Hz, PdPPh ₃ ), 11.2 (d, ² JPP = 24 Hz, P(dma) ₃ ). XRD: The isolated crystalline product was suitable for single crystal X-ray structure determination.

[Chlorido{tris[tris(pyrrolidino)phosphazenyl]phosphane}go ld(I)]

A (dma)P ₃ P containing solution (20 mL, 518 µmol, 1.00 eq), prepared according to the general procedure, was added to a suspension of [(chlorido)(triphenylphosphane)gold(I)] (256 mg, 517 µmol, 1.00 eq) in toluene (10 mL). All volatiles were removed in vacuo, the residue dissolved in boiling n-hexane (20 mL) and filtered hot. [Chlorido{tris[tris(pyrrolidino)phosphazenyl]phosphane}gold( I)] (340 mg, 428 µmol, 83%) was crystallized at -25 °C as colourless solid and washed once with cold n-pentane (5 mL).

[C18H54AuClN12P4] (795.03 g∙mol ^-1 ) ¹ H-NMR (300.3 MHz, C ₆ D ₆ ): d (ppm) = 2.65 (d, ³ JPH = 10 Hz, 54H). ¹³ C{ ¹ H}-NMR (75.5 MHz, C ₆ D ₆ ): d (ppm) = 37.9 (d, ² J _PC = 4 Hz). ³¹ P{ ¹ H}- NMR (121.5 MHz, C ₆ D ₆ ): d (ppm) = 22.3 (q, ² J _PP = 40 Hz, PAu), 15.3 (d, ² J _PP = 40 Hz, P(dma) ₃ ). LIFDI(+)-MS (toluene): m/z (%) = 597.3 (100) [M-Au] ⁺ , 794.3 (70) [M] ⁺ .

LIFDI(+)-HRMS: m/z [M] ⁺ calcd.794.28989, found 794.28457. Elemental analysis:

calcd. C 27.19%, H 6.85%, N 21.14%; found C 27.35%, H 6.80%, N 21.51%. XRD: The isolated crystalline product was suitable for single crystal X-ray structure determination.

Tris(dimethylamino)phosphazenyl-bis(tert-butyl)phosphine To a solution of tris(dimethylamino)phosphazenyl-phosphorusdichloride (0.77g, 2.76mmol, 1.00eq.) in Et2O (50mL) tert-BuLi (3.0mL of 1.88 M solution, 5.66 mmol, 2.05 eq.) was added dropwise at -78° C over 1h. Afterwards the solution was allowed to warm to RT and stirred overnight. The mixture was filtered over celite, the filter cake washed with Et2O (3 x 20 mL) and the solvent removed in vacuo. tris(dimethylamino)phosphazenyl-bis(tert-butyl)phosphine (0.81 g,

2.51mmol, 91%) was obtained as a colourless solid.

1H-NMR (C ₆ D ₆ ):d(ppm) = 2.33(d, ³ J(P,H)= 9.5 Hz, 18 H, N-CH ₃ ),1.18(d, ³ J(P,H) = 10.5 Hz, 18 H, C-CH ₃ ). ¹³ C-NMR (C ₆ D6):d(ppm) =36.9(t, ² J(P,C) = 2.5 Hz, P(V)-NCH ₃ ),33.7(dd, ¹ J(P,C) = 12.4 Hz, P(III)-C),27.7(d, ² J(P,C) = 16.2 Hz, C- CH ₃ ). ³¹ P{ ¹ H}-NMR (C ₆ D ₆ ):d(ppm) =85.4(d, ² J(P,P) = 100.5 Hz, P(III)),31.4(d, ² J(P,P) = 100.5 Hz, P(V)). LIFDI(+)-MS(THF): m/z (%) = 323.24 (100)

[M+H] ⁺ . LIFDI(+)-HRMS: m/z [M+H]+ calc.323.24750, found 323.24934.

Tris(pyrrolidino)phosphazenyl-bis(tert-butyl)phosphine To a solution of tris(pyrrolidino)phosphazenyl-phosphorus dichloride (2.0 g, 5.60 mmol, 1.00 eq.) in Et2O (75 mL) was added tert-BuLi (6.11 mL of 1.88M solution in THF, 11.48mmol, 2.05eq.) dropwise at -78°C. After stirring the mixture for one hour at this temperature, the mixture was allowed to reach RT overnight. All volatile components were removed in vacuo and the residue redissolved in pentane (30mL). The reaction mixture was filtered over celite and the filter cake was washed with pentane(3 x10 mL) afterwards the solvent was removed in vacuo. tris(pyrrolidino)phosphazenyl- bis-tert-butyl phosphine (2.1 g, 5.12 mmol, 91 %) was obtained as a colourless solid. ¹ H-NMR (C ₆ D ₆ ):d(ppm) =3.15(m, 12 H, NCH ₂ CH ₂ ),1.58(m, 12 H, NCH ₂ CH ₂ ), 1.42(d, ³ J(P,H) = 10.4 Hz, 18 H, CCH ₃ ). ¹³ C-NMR (C ₆ D ₆ ):d(ppm)=47.2(d, ² J(C,P) = 2.3 Hz, NCH ₂ CH ₂ ),28.6(d, ² J(C,P) = 16.2 Hz, CCH ₃ ),26.3(d, ³ J(C,P) = 7.3 Hz, NCH ₂ CH ₂ ). ³¹ P{ ¹ H}-NMR (C ₆ D ₆ ):d(ppm) =82.4(d, ² J(P,P) = 94.8 Hz, P(III)),15.8(d,

2J(P,P)=94.8Hz,P(V)). LIFDI(+)-MS(THF): m/z(%) = m/z:401.29(100.0%) [M+H] ⁺ . LIFDI(+)-HRMS: m/z [M+H]+ calc.401.29629, found 401.29823. Tris(tert-butyl)phosphazenyl-bis-tert-butylphosphine To a solution of Tris(tert-butyl) phosphazenyl phosphorus dichloride (318.2 mg, 1.00 mmol, 1.00eq.) in Et2O(50 mL)was added tert-BuLi

(1.09mLof1.88Msolution, 2.05 mmol, 2.05 eq.) dropwise at -78°C. The reaction mixture was stirred at this temperature for 1 h and afterwards was stirred overnight at RT. The solvent was re-moved in vacuo and the residue was redissolved in pentane. The solution was filtered over celite and the solvent was removed in vacuo. Tris(tert-butyl)phosphazenyl) bis-tert-butylphosphane(320.5 mg, 0.88 mmol, 88 %)was obtained as a colourless solid.

1H-NMR (C ₆ D ₆ ):d(ppm) =1.40(d, ³ J(P,H) = 10.1 Hz, 12 H, P(III)CCH ₃ ),1.32

(d, ³ J(P,H) = 12.6 Hz, 18 H, P(V)CCH ₃ . ¹³ C-NMR(C ₆ D6): d(ppm) =41.8 (d, ¹ J(P,C) = 52.0Hz, ³ J(P,C)=2.3Hz,CCH ₃ ), 41.4(d, ¹ J(P,C)= 52.0 Hz,CCH ₃ ),30.5(d, ² J(P,C)= 3.0 Hz, CCH ₃ ),29.8(d, ² J(P,C) = 16.3 Hz, CCH ₃ ). ³¹ P{ ¹ H}-NMR (C ₆ D6):d(ppm) =90.4(d, ² J(P,P) = 26.7 Hz, P(III)),39.3(d, ² J(P,P) = 26.7 Hz, P(V)). LIFDI(+)- MS(THF): m/z (%) = m/z: 362.3 (100.0%) [M+H] ⁺ . LIFDI(+)-HRMS: m/z [M+H]+ calc.362.31055, found 362.30675.

Bis(tris(dimethylamino)phosphazenyl-(tert-butyl)phosphine A solution of n BuLi (0.55 g, 8.55 mmol, 1.9 eq., 3.42 mL (2.5 M solution)) was added dropwise to a solution of tris(dimethylamino)phosphazene (1.60 g, 2.00 eq., 9.0 mmol) in Et2O (50 mL) at -78°C over a period of 30 minutes. This mixture was stirred for 1 h at -78°C. Afterwards a solution of tBuPCl ₂ in Et ₂ O (50 mL) was added dropwise. The mixture was stirred at -78°C for 1 h and at RT overnight. The solvent was removed in vacuo and the residue was redissolved in pentane (50 mL). The resulting solution was filtered over celite and the solvent was removed.

Bis(tris(dimethylamino)phosphazenyl-(tert-butyl)phosphine was obtained as a colourless oil (1.3g, 2.8mmol, 64%). ¹ H-NMR (C ₆ D ₆ ):d(ppm) =2.60(d, ³ J(P,H)= 9.8 Hz, NCH ₃ ),1.44(d, ³ J(P,H) =11.4 Hz, CH ₃ ). ¹³ C-NMR (C ₆ D ₆ ):d(ppm) =37.6(t, ² J(P,C) = 3.2 Hz, NCH ₃ ),37.1 (dd, ¹ J(P,C) = 22.0 Hz, ³ J(P,C) = 3.8 Hz,CCH ₃ ),25.6(d, ² J(P,C) = 18.3 Hz, CCH ₃ ). ³¹ P{ ¹ H}-NMR (C ₆ D ₆ ):d(ppm) =87.3(t, ² J(P,P) = 59.3 Hz, P(III)),20.4(d, ² J(P,P) = 59.3 Hz, P(V)). LIFDI(+)-MS(THF): m/z (%) = m/z: 442.30 (100.0%) [M+H] ⁺ . LIFDI(+)-HRMS: m/z [M+H]+ calc.443.30583, found 443.30559.

Palladium Complex [(tris(dimethylamino)phosphazenyl-bis(tert-butyl)phosphine) (h ³ -cinnamyl)PdCl]

To a solution of tris(dimethylamino)phosphazenyl-bis(tert-butyl)phosphine (322.42 mg, 1 mmol, 1.0 eq.) in THF (10 mL) palladium(p-cinnamyl) chloride dimer (259.04 mg, 0.5 mmol, 0.5 eq.) is added and stirred overnight. Afterwards the solvent was removed and the residue was washed with cold n-pentane. [(tris(dimethylamino)phosphazenyl-bis(tert-butyl)phosphine)( h ³ -cinnamyl)PdCl] was obtained as a yellow air-stable solid (541 mg, 0.93 mmol, 93%).

1H-NMR (C ₆ D ₆ ):d(ppm) = (m, 5 H, ArH), (m, 1 H, Allyl-H), (m, 1 H,Allyl-H), 3.16(d, ³ J(P,H)= 8.8 Hz, 2 H, Allyl-H),2.74(d, ³ J(P,H)= 9.8 Hz, 18 H NCH ₃ ),1.38 (d, ³ J(P,H) = 14.2 Hz, 18 H, CH ₃ ). ¹³ C- NMR(C ₆ D ₆ ):d(ppm)=139.8(d,J(P,C)=7.2Hz,Ar-C),130.2(d,J(P,C) = 1.9 Hz, Ar- C),129.2(d,J(P,C)= 3.6 Hz, Ar-C),128.7(d,J(P,C)=2.5 Hz, Ar-C),112.4(d,J(P,C)= 5.9 Hz, Ar-C),102.5(d,J(P,C)= 28.2 Hz, Ar-H),50.7(d, J(P,C)= 4.7 Hz, Allyl- C),42.1(d,J(P,C)= 2.7 Hz, Allyl-C),41.8(d,J(P,C) = 2.7Hz,Allyl-C),39.6

(d, ² J(P,C)=4.5Hz,NCH ₃ ), 30.8 (d, ² J(P,C) = 7.3Hz,CCH ₃ ). ³¹ P{ ¹ H}-NMR

(C ₆ D ₆ ):d(ppm) =96.6(d, ² J(P,P)= 6.5 Hz, P(tBu ₂ )),13.4(d,

2J(P,P) = 6.5 Hz, P(dma) ₃ ).

Tris(dimethylamino)phosphazenyl-bis(tert-butyl)phosphine tricarbonyl nickel A solution of tris(dimethylamino)phosphazenyl-bis(tert-butyl)phosphine (64.48 mg, 1.00 eq, 0.2 mmol) in toluene (5 mL) was added dropwise to a solution of Ni(CO) ₄ (40.98 mg, 1.20 eq., 0.24 mmol) in toluene (5 mL). The mixture was stirred for 1 h. Afterwards the solvent was removed in vacuo, the residue dissolved in pentane and filtered through a syringe filter. The solvent was removed in vacuo to yield [Tris(dimethylamino)phosphazenyl]bis(tert- butyl)phosphinenickeltricarbonyl as a red solid.

1H-NMR (C ₆ D ₆ ):d(ppm) = 2.31(d, 18 H, ³ J(P,P) = 9.8 Hz, NCH ₃ ),1.30(d, 18 H, ³ J(P,P) = 13.0 Hz, CCH ₃ ). ¹³ C-NMR(C ₆ D6): d(ppm) = 200.0(d, ² J(P,C) =

2.3Hz,CO), 38.3(dd, ¹ J(P,C) = 13.9 Hz, ³ J(P,C)= 5.0 Hz,CCH ²

3),37.3(d, J(P,C)= 4.4 Hz, NCH ₃ ), 28.4(d, ² J(P,C) = 8.1 Hz, CCH ₃ ). ³¹ P{ ¹ H}-NMR (C ₆ D ₆ ): d(ppm) = 101.4(d, ² J(P,P) = 16.4 Hz), 13.4(d, ² J(P,P) = 16.4 Hz). IR(neat): n˜ [cm ^-1 ]: 2893 (w,CH ₃ ), 2803 (w,CH ₃ ,2040 (s,CO), 1948 (vs,CO), 1480(w), 1456(m), 1386(m), 1315(m), 1261(m), 1184(m), 1100(m),1064(m), 1017(m), 976 (s), 803 (m), 725 (m), 601 (w), 573 (w), 487 (m), 454 (s). LIFDI(+)-MS(THF): m/z (%) = m/z:

464.16 (100.0%) [M+H]. LIFDI(+)-HRMS: m/z [M+H]+ calc.464.16161, found 464.16307.

Tris(pyrrolidino)phosphazenyl]bis(tert-butyl)phosphine tricarbonyl nickel A solution of tris(pyrrolidino)phosphazenyl-bis(tert-butyl)phosphine (80.11 mg, 1.00 eq, 0.2 mmol) in toluene (5 mL) was added dropwise to a solution of

Ni(CO)4 (40.98mg, 1.20 eq., 0.24 mmol) in toluene (5 mL). The mixture was stirred for 1h. Afterwards the solvent was removed in vacuo, the residue dissolved in pentane and filtered through a syringe filter. The solvent was removed in vacuo to yield tris(pyrrolidino)phosphazenyl-bis(tert-butyl)phosphine nickel tricarbonyl as a red solid.

1H-NMR (C ₆ D ₆ ):d(ppm) =2.79(m, 12 H, NCH ₂ CH ₂ ),1.28(m, 12 H, NCH ₂ CH ₂ ), 1.15(d, ³ J(P,H) = 13.0 Hz, 18 H, C(CH ₃ ) ₃ ). ¹³ C-NMR (C ₆ D ₆ ):d(ppm) =200.5(d, ² J(P,C) = 2.5 Hz,CO),47.1(d, ² J(P,C) = 4.6 Hz, NCH ₂ CH ₂ ),38.5(dd, ³ J(P,C)= 5.2 Hz,CCH ₃ ),28.8(d, ² J(P,C)= 8.1 Hz, CCH ₃ ),26.4(d, ³ J(P,C)= 8.2Hz, NCH ₂ CH ₂ ). ³¹ P{ ¹ H}- NMR (C ₆ D ₆ ):d(ppm) = 100.0 (d, ² J(P,P) = 24.2 Hz, P(III)), 0.5(d, ² J(P,P) = 24.2 Hz, P(V)). IR(neat): n˜[cm ^-1 ]: 2960(w,CH ₃ ), 2866 (w,CH ₃ ,2042 (s,CO),1974 (vs,CO),1947 (vs), 1259 (m), 1195 (w), 1070 (s), 1008 (vs), 934 (w), 914 (w), 865 (w), 795 (s),582 (w), 560 (w), 489 (w), 467 (m), 447 (s). LIFDI(+)-MS(THF): m/z (%) = m/z: 542.21 (100.0%) [M+H] ⁺ . LIFDI(+)-HRMS: m/z [M+H]+ calc.542.20856, found 542.21002.

Tris(tert-butylphosphazenyl-bis(tert-butyl)phosphine tricarbonyl nickel A solution of tris(tert-butyl)phosphazenyl-bis(tert-butyl)phosphine (50.0 mg, 1.00eq, 0.14 mmol) in toluene (5 mL) was added dropwise to a solution of Ni(CO) ₄ (28.3mg, 1.20 eq., 0.17 mmol) in toluene (5 mL). The mixture was stirred for 1 h. Afterwards the solvent was removed in vacuo, the residue dissolved in pentane and filtered through a syringe filter. The solvent was removed in vacuo to yield tris(tert- butyl)phosphazenyl-bis(tert-butyl)phosphine tricarbonyl nickel as a red solid.

1H-NMR (C ₆ D ₆ ):d(ppm) =1.38(d, ³ J(P,H) = 17.3 Hz, 12 H, P(III)CCH ₃ ),1.26

(d, ³ J(P,H) = 10.9 Hz, 18 H, P(V)CCH ₃ ). ¹³ C-NMR (C ₆ D ₆ ):d(ppm) =199.8(d, ² J(P,C)= 1.8 Hz,CO),42.2(d, ¹ J(P,C) = 2.0Hz, CCH ₃ ), 41.5 (d, ¹ J(P,C) = 2.0Hz,CCH ₃ ), 30.2

(d, ² J(P,C) = 7.8Hz,CCH ₃ ), 27.2(d, ² J(P,C)= 8.2Hz, CCH ₃ ). ³¹ P{ ¹ H}-NMR (C ₆ D ₆ ):d(ppm) =108.8(d, ² J(P,P) = 25.8 Hz, P(III)), 38.0 (d, ² J(P,P) = 25.8 Hz, P(V)). IR(neat): n˜[cm- ¹ ]: 2908.1 (br,m,CH ₃ ), 2039.4(s,CO),1951.6(vs,CO),1472.9(m), 1390.6 (m), 1248.6 (vs), 1165.8 (vs), 1011.1 (w), 933.82 (w), 805.42 (m),618.9 (m), 491.6 (w), 448.2( m ) .

[Bis(tris(dimethylamino)phosphazenyl]-(tert-butyl) phosphine nickel tricarbonyl A solution of [Bis(tris(dimethylamino)phosphazenyl]-(tert-butyl) phosphine (88.51 mg, 1.00 eq, 0.2 mmol) in toluene (5 mL)was added dropwise to a solution of Ni(CO)4 (41.0 mg, 1.20 eq., 0.24 mmol) in toluene (5 mL). The mixture was stirred for 1 h. Afterwards the solvent was removed in vacuo, the residue dissolved in pentane and filtered through a syringe filter. The solvent was removed in vacuo to yield [Bis(tris(dimethylamino)phosphazenyl]-(tert-butyl) phosphine nickel tricarbonyl as a red solid. ¹ H-NMR (C ₆ D ₆ ):d(ppm) =2.48(d, ³ J(P,H) = 9.9 Hz, 36 H, NCH ₃ ),1.40(d, ³ J(P,H)= 15.0Hz, 9 H, CH ₃ ). ¹³ C-NMR(C ₆ D ₆ ): d (ppm) =202.0 (d, ² J(P,C) =4.6Hz,CO),

39.8(dd, ¹ J(P,C)=

34.3Hz, ³ J(P,C)=21.6Hz,C CH ₃ ),37.5(d, ² J(P,C)=4.5Hz,N CH ₃ ),25.8(d,

2J(P,C) = 9.6 Hz, CCH ₃ ). ³¹ P{ ¹ H}-NMR (C ₆ D ₆ ):d(ppm) =79.8(t, ² J(P,P) = 5.0 Hz, P(III)),7.5(d, ² J(P,P) = 5.0 Hz, P(V)). IR(neat):n˜[cm ^-1 ]: 2966.1

(w,CH ₃ ),2877.3(w,CH ₃ ),2796.5(w,CH ₃ ),2032.1(m, CO), 1942.9 (vs, CO), 1456.8 (w), 1375.9 (w), 1348.7 (w), 1309.5 (m), 1256.2(s), 1188.1 (s), 1143.6 (m), 1092.3 (m), 1062.9 (m), 1019.2 (m), 969.4 (vs),865.0 (w), 798.8 (m), 749.7 (m), 727.4 (m), 641.8 (w), 597.4 (w), 574.0 (w), 484.8 (w), 460.8 (m), 433.7 (w).

[Tris(dimethylamino)phosphazenyl]bis(tert-butyl)phosphine selenide To a solution of [Tris(dimethylamino)phosphazenyl]bis(tert-butyl)phosphane (64.5 mg, 0.2 mmol, 1.00 eq) in toluene (5 mL) gray selen (19.0 mg, 0.24 mmol, 1.2 eq.)was added and the mixture was stirred at 90°C for 1 h. After cooling to room temperature the mixture was filtered through a syringe filter and all volatile components were removed in vacuo. Afterwards the residue was dissolved in pentane (10 mL) and again filtered through a syringe filter. The solvent was removed in vacuo and [Tris(dimethylamino)phosphazenyl]bis(tert- butyl)phosphane selenide was obtained as a colourless solid.

1H-NMR (C ₆ D ₆ ):d(ppm) =2.4(d, ² J(P,H) = 10.1 Hz, 18 H, P(NCH ₂ ),1.51(d, ³ J(P,H) = 15.3 Hz, -C(CH ₃ )). ¹³ C-NMR (C ₆ D ₆ ):d(ppm) =39.5(dd, ¹ J(P,C)= 57.7 Hz, ⁴ J(C,P) = 4.3Hz, C(CH ₃ ),36.8(d, ² J(C,P)=3.8Hz, P(NCH ₃ ) ₂ ), 27.6 (d, ² J(C,P)= 2.4Hz, C(CH ₃ ) ₃ ). ³¹ P{ ¹ H}-NMR (C ₆ D ₆ ):d(ppm)=75.4 (dd, ¹ J(P,Se)= 696.2Hz,

2J(P,P)=3.7Hz, P=Se), 24.5(d, ² J(P,P)= 3.7 Hz,N=P(NCH ₃ ) ₂ ). ⁷⁷ Se-NMR

(C ₆ D ₆ ):d(ppm)= -267.3 (d, ¹ J(P,Se) = 696.2 Hz. LIFDI(+)-MS(THF): m/z (%) = m/z: 402.16 (100.0%) [M+H] ⁺ .LIFDI(+)-HRMS:m/z[M+H] calc.402.15804, found 402.15897.

[Tris(pyrrolidino)phosphazenyl]bis(tert-butyl)phosphine selenide

To a solution of [Tris(pyrrolidino)phosphazenyl]bis(tert-butyl)phosphine (81.1 mg, 0.2 mmol, 1.00 eq) in toluene (5 mL) gray selen (19.0 mg, 0.24 mmol, 1.2 eq.)was added and the mixture was stirred at 90°C for 1 h. After cooling to room

temperature the mixture was filtered through a syringe filter and all volatile components were removed in vacuo. Afterwards the residue was dissolved in pentane (10 mL) and again filtered through a syringe filter. The solvent was removed in vacuo and [Tris(pyrrolidino)phosphazenyl]bis(tert-butyl)phosphine selenide was obtained as a colourless solid.

1H-NMR (C ₆ D ₆ ):d(ppm) =2.89(m, 12 H, NCH ₂ CH ₂ ),1.37(d, ³ J(P,H) = 15.2 Hz, 18 H, C(CH ₃ ) ₃ ),1.32(m, 12 H, NCH ₂ CH ₂ ). ¹³ C-NMR (C ₆ D ₆ ):d(ppm)=47.2(d, ² J(C,P) = 4.3 Hz, NCH ₂ CH ₂ ),40.3(dd, ¹ J(C,P) = 57.3 Hz, ³ J(C,P) = 4.1

Hz,C(CH ₃ ) ₃ ),28.6(d, ³ J(C,P) = 2.6 Hz, NCH ₂ CH ₂ ), 26.1(d, ² J(C,P) = 7.8 Hz, C(CH ₃ ) ₃ ). ³¹ P{ ¹ H}-NMR (C ₆ D ₆ ):d (ppm)=73.0(dd, ¹ J(P,Se)=690.5Hz, ² J(P,P)=2.1Hz, P=Se), 9.9 (d, ² J(P,P) = 2.1Hz, P(pyrr) ₃ ). ⁷⁷ Se-NMR (C ₆ D ₆ ):d(ppm)= -257 (d, ¹ J(P,Se) = 690.5Hz). LIFDI(+)-MS(THF): m/z (%) = m/z: 480.2 (100.0%) [M+H] ⁺ . LIFDI(+)-HRMS: m/z [M+H]+ 480.20499, found 480.20701. [Tris(tert-butyl)phosphazenyl]bis(tert-butyl)phosphine selenide To a solution of [Tris(tert-butyl)phosphazenyl]bis(tert-butyl)phosphine (50.0 mg ,0.14 mmol, 1.00 eq) in toluene (5 mL) gray selen (10.9 mg, 0.14 mmol, 1.00 eq.)was added and the mixturewasstirred at 90°C for 1 h. After cooling to room temperature the mixturewasfiltered through a syringe filter and all volatile

components were re-movedin vacuo. Afterwards the residue was dissolved in pentane (10 mL) and again filtered through a syringe filter. The solventwas removed in vacuoand[Tris(tert- butyl)phosphazenyl]bis(tert-butyl)phosphine selenide was obtained as a colourless solid.

1H-NMR (C ₆ D ₆ ):d(ppm) =1.58(d, ³ J(P,H)= 19.2 Hz12 H, P(III)CCH ₃ ),1.30

(d, ³ J(P,H) = 13.5 Hz18 H, P(V)CCH ₃ ). ¹³ C-NMR (C ₆ D ₆ ): d(ppm) =42.3

(dd, ¹ J(P,C)= 57.2 Hz, ³ J(P,C)=2.4 Hz, CCH ₃ ), 40.6(d, ¹ J(P,C) = 50.8Hz, CCH ₃ ), 29.3 (d, ² J(P,C)= 2.7Hz,CCH ₃ ), 24.5 (d, ² J(P,C)= 3.7Hz, CCH ₃ ). ³¹ P{ ¹ H}- NMR(C ₆ D ₆ ):d(ppm)=75.2(dd, ² J(P,P)=37.8Hz, ¹ J(P,Se)=695.4Hz,P-Se), 45.7(d, ² J(P,P) = 37.8Hz). ⁷⁷ Se-NMR (C ₆ D ₆ ):d(ppm) =-222.5(d, ¹ J(P,Se)= 695.4Hz.

Respresentative examples of catalytic applications of PAP metal complexes

Suzuki cross-coupling reaction

An oven dried schlenk-flask was charged with phenylboronic acid (310.0 mg, 2.54 mmol, 1.5 eq.), sodium methoxide (183.1 mg, 3.39 mol, 2.0 eq) and palladium precursor (39.4 mg, 67.8 µmol, 0.04 eq.). The mixture was dissolved in toluene (6 mL) and 4-chlorotoluene (214.6 mg, 1.7 mmol, 1.0 eq.) was added. The reaction mixture was heated to 80°C for 16h. After this time it was filtered over celite, the solvent was removed in vacuo and the residue was subjected to column chromatography on aluminium oxide (100 % pentane, R _f =0.95). 4- Methyl-1,1’-biphenyl was obtained as a colourless solid (265.0mg,1.6mmol, 93%).

1H-NMR (C ₆ D ₆ ):d(ppm) =7.58(2 H, d, ³ J(H,H) = 7.0 Hz, Ph-H),7.50(2H, d, ³ J(H,H)=8.2Hz,Ph-H),7.42(2H,t, ³ J(H,H)=7.2Hz,Ph-H),7.34(1H,t, ³ J(H,H) = 1.3 Hz, Ph-H),7.26(2 H, ³ J(H,H) = 8.7 Hz, Ph-H),2.38(3 H, s, -CH ₃ ). ¹³ C-NMR (C ₆ D ₆ ):d(ppm) =141.0,138.1,137.2,129.4,128.7,127.0,126.8,20.8.

Bis(tris(dimethylamino)phosphazenyl-tert-butyl)phosphine as ligand in an in situ prepared catalyst ((dma) ₃ PN) ₂ PtBu)PdCl-cinnamyl leads to a product yield of 91% under identical conditions. Buchwald Hartwig coupling

(tBu) ₃ PNPtBu ₂ (10.9 mg, 2 mol%) and Cinnamyl palladium chloride (7.8 mg, 1mol %) were added into an oven dried schlenk and dissolved in THF (5 mL). This mixture was stirred for 1h before being added to a mixture of KOtBu (673.3 mg, 6.0 mmol, 2.00 eq.), 4-chlorotoluene (379.8 mg, 3.0 mmol, 1.00 eq.) and piperidine (255.5mg, 3.0 mmol, 1.00 eq.) in THF (5 mL). The yield of product 1-(p-tolyl)piperidine was determined by the method of internal nmr standard: After 2 h the yield was 74 % and after 24 h the yield was 82 %.

Gold catalysed hydroamination

In an oven dried schlenk anillin (0.26 mL, 2.35 mmol, 1.00 eq.) and phenylacetylen (0.21mL,2.35mmol,1.00eq.) was added. To this mixture AgOTf (3.0 mg, 0.011 mmol, 0.005 eq.) and trisphosphazenyl phosphine catalyst (dma)3PN)3PAuCl (9.3 mg, 0.011 mmol, 0.005 eq.) was added. The reaction mixture was heated to 60°C for 6 h. The yield was determined directly from the crude NMR by Integration of the imine product with the starting phenylacetylene. (Z)-N,1-diphenylethan-1-imine was obtained in a 99 % yield. Under identical conditions the mono-phosphazenyl phosphine catalyst (tBu3PNPtBu ₂ )AuCl gave a yield of 73% and the bis-phosphazenyl phosphine catalyst ((tBu ₃ PN) ₂ PtBu)AuCl gave a yield of 81% (Z)-N,1-diphenylethan-1- imine.

NMR Studies

NMR Titration Experiments

The pK _BH + values of three phosphine super bases (dma)P3P (2), (pyrr)P3P (3),

(dma)P ₄ P (7) were determined via NMR titration. The general procedure for NMR titration experiments for the determination of pK _BH ⁺ values is known to the person skilled in the art. Adding to the initial amount of a super base in its protonated form a similar amount of a Schwesinger base in THF, an equilibrium in competition of protons in solution was quickly reached. In order to have quantitative ³¹ P NMR spectra relaxation times of all ³¹ P signals were first determined using the standard inversion recovery procedure. Quantitative ³¹ P NMR spectra were thus recorded by inverse gated decoupling method with a relaxation delay of 30 s. Therefore, signal intensities of the central phosphorus (P ^III ) in its free and protonated form, as well as the terminal phosphorus (P ^V ) of the Schwesinger base in its free and protonated form, revealed the molar ratio of the different species at equilibrium. On the bases of these signal intensities equilibrium constants were thus calculated and the unknown pK _BH + values determined.

A mixture of (dma)P ₃ P∙HBF ₄ and (dma)P ₄ -tBu (pK _BH ⁺ (THF) = 33.9) in THF did show a neat signal at 82 ppm which was due to P ^III in its free form, whereas in a similar experiment of (pyrr)P ₃ P∙HBF ₄ or (dma)P ₄ P∙HBF ₄ mixed with (dma)P4-tBu, no signal corresponding to the free base could be observed. This meant that a basicity of both higher than that of (dma)P ₄ -tBu could be expected and a stronger base was necessary for the purpose. Thus, experiments were then carried out with (pyrr)P ₄ -tBu (pK _BH + (THF) = 35.3) in THF.

Results. Results of thermal dynamic basicity determination are shown in Tables S1-S3. Thus, the pK _BH + of THF scale of super bases 2, 3 and 7 were determined to be 34.9 ± 0.2, 36.7 ± 0.1 and 37.2 ± 0.1.

Table S1: ³¹ P NMR titration experiments for pK _BH + determination of (dma)P3P (2).

Table S2: ³¹ P NMR titration experiments for pK _BH + determination of (pyrr)P3P (3).

Table S3: ³¹ P NMR titration experiments for pK _BH + determination of (dma)P4P (7).

Crystallographic Details

Data were collected with a Bruker D8 QUEST area detector diffractometer equipped with MoKa radiation, a graded multilayer mirror monochromator (l = 0.71073 Å) and a PHOTON-100 CMOS detector or with a Stoe STADIVARI diffractometer equipped with CuK _a radiation, a graded multilayer mirror monochromator (l = 1.54178 Å) and a DECTRIS PILATUS 300K detector both using an oil-coated shock-cooled crystal at 100(2) K. Data collection, reduction, cell refinement and semi-empirical absorption correction (multi-scan) were performed within Bruker Apex3 or Stoe X-Area. Structures were solved with dual-space methods using ShelXT and refined against F ² with ShelXL, all within the user interface of WinGX and ShelXLe. Carbon bonded hydrogen atoms were calculated in their idealized positions and refined with fixed isotropic thermal parameters. Hydrogen atoms connected to heteroatoms were located on the Fourier map and refined isotropically. All molecular structures were illustrated with Diamond 4 using thermal ellipsoids at the 50% probability level.

The corresponding CIF files providing full information concerning the molecular structures and experimental conditions are deposited at the Cambridge Crystallographic Data Center. The scope of the invention can therefore be summarized as follows: The invention comprises a Metal complex or semi-metal complex according to formula Ia:

The Metal complex or semi-metal complex according to formula Ia is characterized in that

- the metal or semi-metal M is chosen from the list comprising the metals

resp. semi-metals

Fe, Co, Ni, Ru, Rh, Pd, Os, Ir, Pt, Sc, Y, La, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Mn, Re, Cu, Ag, Au, Zn, Cd, Hg, Al, Ga, In, Tl, Si, Ge, Sn, Pb, As, Sb, Bi, Se, Te, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu,

whereat the oxidation number of metal or semi-metal M may

be 0, +1, +2, +3, +4, +5, +6, +7 or +8 as far as the theory of oxidation

number allows the oxidation number of the certain metal or semi-metal M to accept the specific value;

- the substituents R are

i) independently from each other chosen from the list comprising

the substituents methyl, ethyl, propyl, n-alkyl, iso-alkyl, sec-alkyl, tert-alkyl, cycloalkyl, phenyl, benzyl, aryl, heteroaryl, allyl,

NR’ ₂ , NHR’, NR’R’’, N-pyrrolidino, N-piperidino, N-morpholino, N-tetraalkylguanidino (-N=C(NR ₂ ) ₂ ), N-phosphazenyl (-N=P(NR ₂ ) ₃ ), or

ii) two substituents R chemically bound to the same P form a chelate ring with each other derived from secondary 1,2- and 1,3-diamines such as derivatives of N,N’-dialkyl-1,2-ethanediamine,

N,N’-dialkyl-1,3-propanediamine,

N,N’-dialkyl-1,2-cyclohexanediamine,

1,4-butandiyl, 1,5-hexandiyl,

whereat the substituents R’ are independently from each other

chosen from the list comprising

the substituents H, methyl, ethyl, propyl, n-alkyl, iso-alkyl, sec-alkyl, tert-alkyl, cycloalkyl, phenyl, benzyl, aryl, heteroaryl, allyl , OR, NR ₂ , pyrrolidino, piperidino, morpholino;

and the substituents R’’ are independently from each other chosen from the list comprising the substituents methyl, ethyl, propyl, n-alkyl, iso-alkyl, sec-alkyl, tert-alkyl, cycloalkyl, phenyl, benzyl, aryl, heteroaryl, allyl, OR, NR ₂ , pyrrolidino, piperidino, morpholino;

- the ligands L are independently from each other chosen from the list comprising NO, CO, PR’’’’ ₃ , NR’’’’ ₃ , R’’’’NH ₂ , NH ₃ , H ₂ O, R’’’’OH, R’’’’OR’’’’, alkene, alkyne, arene, carbenes such as CHPh or N-heterocyclic carbenes (NHC), whereat substituents R’’’’ are independently chosen from the list comprising the substituents methyl, ethyl, propyl,

n-alkyl, iso-alkyl, sec-alkyl, tert-alkyl,

cycloalkyl, phenyl, benzyl, aryl.;

- the ligands X are independently from each other chosen from the list of formally anionic ligands comprising H, F, Cl, Br, I, OH, OR, NR ₂ , CN, CH ₃ , C ₂ H ₅ , substituted or unsubstituted alkyl ligands, H, C ₆ H ₅ , substituted or unsubstituted aryl ligands, C ₅ H ₅ , substituted or unsubstituted

cyclopentadienyl ligands, C ₃ H ₅ , substituted or unsubstituted allyl ligands, C ₂ H ₃ , substituted or unsubstituted vinyl ligands, CCMe, substituted or unsubstituted 1-alkinyl ligands, COMe, substituted or unsubstituted acyl ligands, SiR3, substituted or unsubstituted silyl ligands, formally dianionic ligands O (oxo), NR (organoimido), CHR, CR ₂ (alkylidene),

O ₂ (peroxo), formally trianionic: N (nitrido), CR (alkylidyne);

- the indexes a, b and c have independently from each other values ranging from 1 through p, whereat p is a positive integer numeral; - index m is an integer numeral having a value of 0, 1, 2, 3, 4, 5 or 6 and index n is an integer numeral having a value of 0, 1, 2, 3, 4, 5 or 6 whereat the sum of indexes m and n is maximum 8;

- index o is an integer numeral having a value of 1 or 2. The invention further comprises a Metal complex or semi-metal complex according to formula Ib:

The Metal complex or semi-metal complex according to formula Ib is characterized in that

- the metal or semi-metal M is chosen from the list comprising the metals resp. semi-metals

Fe, Co, Ni, Ru, Rh, Pd, Os, Ir, Pt, Sc, Y, La, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Mn, Re, Cu, Ag, Au, Zn, Cd, Hg, Al, Ga, In, Tl, Si, Ge, Sn, Pb, As, Sb, Bi, Se, Te, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu,

whereat the oxidation number of metal or semi-metal M may

be 0, +1, +2, +3, +4, +5, +6, +7 or +8 as far as the theory of oxidation number allows the oxidation number of the certain metal or semi-metal M to accept the specific value;

- the substituents R are

i) independently from each other chosen from the list comprising

the substituents methyl, ethyl, propyl, n-alkyl, iso-alkyl, sec-alkyl, tert-alkyl, cycloalkyl, phenyl, benzyl, aryl, heteroaryl, allyl,

NR’ ₂ , NHR’, NR’R’’, N-pyrrolidino, N-piperidino, N-morpholino, N-tetraalkylguanidino (-N=C(NR ₂ ) ₂ ), N-phosphazenyl (-N=P(NR ₂ ) ₃ ), or

ii) two substituents R chemically bound to the same P form a chelate ring with each other derived from secondary 1,2- and 1,3-diamines such as derivatives of N,N’-dialkyl-1,2-ethanediamine,

N,N’-dialkyl-1,3-propanediamine,

N,N’-dialkyl-1,2-cyclohexanediamine,

1,4-butandiyl, 1,5-hexandiyl,

whereat the substituents R’ are independently from each other

chosen from the list comprising

the substituents H, methyl, ethyl, propyl, n-alkyl, iso-alkyl, sec-alkyl, tert-alkyl, cycloalkyl, phenyl, benzyl, aryl, heteroaryl, allyl , OR, NR ₂ , pyrrolidino, piperidino, morpholino;

and the substituents R’’ are independently from each other chosen from the list comprising the substituents methyl, ethyl, propyl, n-alkyl, iso-alkyl, sec-alkyl, tert-alkyl, cycloalkyl, phenyl, benzyl, aryl, heteroaryl, allyl, OR, NR ₂ , pyrrolidino, piperidino, morpholino;

- the ligands L are independently from each other chosen from the list comprising NO, CO, PR’’’’ ₃ , NR’’’’ ₃ , R’’’’NH ₂ , NH ₃ , H ₂ O, R’’’’OH, R’’’’OR’’’’, alkene, alkyne, arene, carbenes such as CHPh or N-heterocyclic carbenes (NHC), whereat substituents R’’’’ are independently chosen from the list comprising the substituents methyl, ethyl, propyl,

n-alkyl, iso-alkyl, sec-alkyl, tert-alkyl,

cycloalkyl, phenyl, benzyl, aryl.;

- the ligands X are independently from each other chosen from the list of formally anionic ligands comprising H, F, Cl, Br, I, OH, OR, NR ₂ , CN, CH ₃ , C ₂ H ₅ , substituted or unsubstituted alkyl ligands, H, C ₆ H ₅ , substituted or unsubstituted aryl ligands, C ₅ H ₅ , substituted or unsubstituted

cyclopentadienyl ligands, C ₃ H ₅ , substituted or unsubstituted allyl ligands, C ₂ H ₃ , substituted or unsubstituted vinyl ligands, CCMe, substituted or unsubstituted 1-alkinyl ligands, COMe, substituted or unsubstituted acyl ligands, SiR3, substituted or unsubstituted silyl ligands, formally dianionic ligands O (oxo), NR (organoimido), CHR, CR ₂ (alkylidene),

O ₂ (peroxo), formally trianionic: N (nitrido), CR (alkylidyne);

- the indexes a and b have independently from each other values ranging from 1 through p, whereat p is a positive integer numeral; - index m is an integer numeral having a value of 0, 1, 2, 3, 4, 5 or 6 and index n is an integer numeral having a value of 0, 1, 2, 3, 4, 5 or 6 whereat the sum of indexes m and n is maximum 8;

- index o is an integer numeral having a value of 1 or 2;

- R’’’’ is chosen from the list comprising the substituents methyl, ethyl, propyl, n-alkyl, iso-alkyl, sec-alkyl, tert-alkyl,

cycloalkyl, phenyl, benzyl, aryl. The invention further comprises a Metal complex or semi-metal complex according to formula Ic:

o

The Metal complex or semi-metal complex according to formula Ic is characterized in that

- the metal or semi-metal M is chosen from the list comprising the metals resp. semi-metals

Fe, Co, Ni, Ru, Rh, Pd, Os, Ir, Pt, Sc, Y, La, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Mn, Re, Cu, Ag, Au, Zn, Cd, Hg, Al, Ga, In, Tl, Si, Ge, Sn, Pb, As, Sb, Bi, Se, Te, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu,

whereat the oxidation number of metal or semi-metal M may

be 0, +1, +2, +3, +4, +5, +6, +7 or +8 as far as the theory of oxidation number allows the oxidation number of the certain metal or semi-metal M to accept the specific value;

- the substituents R are

i) independently from each other chosen from the list comprising

the substituents methyl, ethyl, propyl, n-alkyl, iso-alkyl, sec-alkyl, tert-alkyl, cycloalkyl, phenyl, benzyl, aryl, heteroaryl, allyl,

NR’ ₂ , NHR’, NR’R’’, N-pyrrolidino, N-piperidino, N-morpholino, N-tetraalkylguanidino (-N=C(NR ₂ ) ₂ ), N-phosphazenyl (-N=P(NR ₂ ) ₃ ), or

ii) two substituents R chemically bound to the same P form a chelate ring with each other derived from secondary 1,2- and 1,3-diamines such as derivatives of N,N’-dialkyl-1,2-ethanediamine,

N,N’-dialkyl-1,3-propanediamine,

N,N’-dialkyl-1,2-cyclohexanediamine,

1,4-butandiyl, 1,5-hexandiyl,

whereat the substituents R’ are independently from each other

chosen from the list comprising

the substituents H, methyl, ethyl, propyl, n-alkyl, iso-alkyl, sec-alkyl, tert-alkyl, cycloalkyl, phenyl, benzyl, aryl, heteroaryl, allyl , OR, NR ₂ , pyrrolidino, piperidino, morpholino;

and the substituents R’’ are independently from each other chosen from the list comprising the substituents methyl, ethyl, propyl, n-alkyl, iso-alkyl, sec-alkyl, tert-alkyl, cycloalkyl, phenyl, benzyl, aryl, heteroaryl, allyl, OR, NR ₂ , pyrrolidino, piperidino, morpholino;

- the ligands L are independently from each other chosen from the list comprising NO, CO, PR’’’’ ₃ , NR’’’’ ₃ , R’’’’NH ₂ , NH3, H ₂ O, R’’’’OH, R’’’’OR’’’’, alkene, alkyne, arene, carbenes such as CHPh or N-heterocyclic carbenes (NHC), whereat substituents R’’’’ are independently chosen from the list comprising the substituents methyl, ethyl, propyl,

n-alkyl, iso-alkyl, sec-alkyl, tert-alkyl,

cycloalkyl, phenyl, benzyl, aryl.;

- the ligands X are independently from each other chosen from the list of formally anionic ligands comprising H, F, Cl, Br, I, OH, OR, NR ₂ , CN, CH ₃ , C ₂ H ₅ , substituted or unsubstituted alkyl ligands, H, C ₆ H ₅ , substituted or unsubstituted aryl ligands, C ₅ H ₅ , substituted or unsubstituted

cyclopentadienyl ligands, C ₃ H ₅ , substituted or unsubstituted allyl ligands, C ₂ H ₃ , substituted or unsubstituted vinyl ligands, CCMe, substituted or unsubstituted 1-alkinyl ligands, COMe, substituted or unsubstituted acyl ligands, SiR ₃ , substituted or unsubstituted silyl ligands, formally dianionic ligands O (oxo), NR (organoimido), CHR, CR ₂ (alkylidene), O ₂ (peroxo), formally trianionic: N (nitrido), CR (alkylidyne);

- index a has a value ranging

from 1 through p, whereat p is a positive integer numeral;

- index m is an integer numeral having a value of 0, 1, 2, 3, 4, 5 or 6 and index n is an integer numeral having a value of 0, 1, 2, 3, 4, 5 or 6 whereat the sum of indexes m and n is maximum 8;

- index o is an integer numeral having a value of 1 or 2;

- substituents R’’’’ are independently from each other chosen from the list comprising the substituents methyl, ethyl, propyl, n-alkyl, iso-alkyl, sec-alkyl, tert-alkyl,

cycloalkyl, phenyl, benzyl, aryl. The invention further comprises a Process for manufacturing of a compound as previously described (formula Ia), characterized in that the process comprises the following steps:

a) reacting an electrophile R’’’ ₂ PX with built-in auxiliary base and

phosphazene according to formula II,

,

in an aprotic organic solvent,

whereat the substituents R are

i) independently from each other chosen from the list comprising

the substituents methyl, ethyl, propyl, n-alkyl, iso-alkyl, sec-alkyl, tert-alkyl, cycloalkyl, phenyl, benzyl, aryl, heteroaryl, allyl, NR’ ₂ , NHR’, NR’R’’, N-pyrrolidino, N-piperidino, N-morpholino, N-tetraalkylguanidino (-N=C(NR ₂ ) ₂ ), N-phosphazenyl (-N=P(NR ₂ ) ₃ ), or

ii) two substituents R chemically bound to the same P form a chelate ring with each other derived from secondary 1,2- and 1,3-diamines such as derivatives of N,N’-dialkyl-1,2-ethanediamine

(-RN-CH ₂ CH ₂ -NR-), N,N’-dialkyl-1,3-propanediamine

(-RN-CH ₂ CH ₂ -CH ₂ -NR-), or N,N’-dialkyl-1,2-cyclohexanediamine, 1,4-butandiyl, 1,5-hexandiyl,

whereat the substituents R’ are independently from each other

chosen from the list comprising

the substituents H, methyl, ethyl, propyl, n-alkyl, iso-alkyl, sec-alkyl, tert-alkyl, cycloalkyl, phenyl, benzyl, aryl, heteroaryl, allyl , OR, NR ₂ , pyrrolidino, piperidino;

and the substituents R’’ are independently from each other chosen from the list comprising the substituents methyl, ethyl, propyl, n-alkyl, iso-alkyl, sec-alkyl, tert-alkyl, cycloalkyl, phenyl, benzyl, aryl, heteroaryl, allyl, OR, NR ₂ , pyrrolidino, piperidino;

and X is chosen from the list comprising Cl, Br, I;

and R’’’ is NMe ₂ or NEt ₂ or pyrrolidyl or a combination of two of them; index a has a value ranging from 1 through p, whereat p

is a positive integer numeral;

whereat the intermediate-product of this step is obtained as a

hydrohalogenide salt;

b) precipitating of the salt of the intermediate-product of step a) with a

weakly coordinating anion chosen from the list comprising the weakly coordinating anions (WCA)

tetrafluoridoborate, tetraphenylborate,

hexafluorophosphate, hexafluoroantimonate, hexafluoroarsenate, triflate, bistryiflylimide by dissolving the intermediate product

hydrohalogenide salt of

step a) in a minimum amount of water, thus creating a saturated or nearly saturated aqueous solution, adding a saturated or nearly saturated solution of the respective sodium salt of the weakly coordinating anion under stirring,

separating the precipitated salt of the intermediate-product of step a) with the weakly coordinating anion

being formed, rinsing it and drying it;

c) deprotonating of the salt with the weakly coordinating anion from

step b) by reacting it with

a metal amide within an organic solvent to the P(III) Brønsted or

Lewis superbase, obtaining a suspension containing the P(III) Brønsted or Lewis superbase; d) separating the suspension from step c) into the organic solution of the P(III) Brønsted or Lewis superbase and the residue;

e) reacting the P(III) Brønsted or Lewis superbase solution from step d) or the suspension containing the P(III) Brønsted or Lewis superbase from step c) with a metal or semi-metal complex of formula ML _m X _n whereat - the metal or semi-metal M is chosen from the list comprising the metals resp. semi-metals

Fe, Co, Ni, Ru, Rh, Pd, Os, Ir, Pt, Sc, Y, La, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Mn, Re, Cu, Ag, Au, Zn, Cd, Hg, Al, Ga, In, Tl, Si, Ge, Sn, Pb, As, Sb, Bi, Te, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, whereat the oxidation number of metal or semi-metal M may be 0, +1, +2, +3, +4, +5, +6, +7 or +8 as far as the theory of oxidation number allows the oxidation number of the certain metal or semi- metal M to accept the specific value;

- the ligands L are independently from each other chosen from the list comprising NO, CO, PR’’’’ ₃ , NR’’’’ ₃ , R’’’’NH ₂ , NH ₃ , H ₂ O, R’’’’OH, R’’’’OR’’’’, alkene, alkyne, arene, carbenes such as CHPh or

N-heterocyclic carbenes (NHC), whereat substituents R’’’’ are independently chosen from the list comprising the substituents methyl, ethyl, propyl,

n-alkyl, iso-alkyl, sec-alkyl, tert-alkyl,

cycloalkyl, phenyl, benzyl, aryl;

- the ligands X are independently from each other chosen from the list of formally anionic ligands comprising H, F, Cl, Br, I, OH, OR, NR ₂ , CN, CH ₃ , C ₂ H ₅ , substituted or unsubstituted alkyl ligands, H, C ₆ H ₅ , substituted or unsubstituted aryl ligands, C ₅ H ₅ , substituted or unsubstituted cyclopentadienyl ligands, C ₃ H ₅ , substituted or unsubstituted allyl ligands, C ₂ H ₃ , substituted or unsubstituted vinyl ligands, CCMe, substituted or unsubstituted 1-alkinyl ligands, COMe, substituted or unsubstituted acyl ligands,

SiR ₃ , substituted or unsubstituted silyl ligands, formally dianionic ligands O (oxo), NR (organoimido), CHR, CR ₂ (alkylidene),

O ₂ (peroxo), formally trianionic: N (nitrido), CR (alkylidyne);

- index m is an integer numeral having a value of 0, 1, 2, 3, 4, 5 or 6 and index n is an integer numeral having a value of 0, 1, 2, 3, 4, 5 or 6 whereat the sum of indexes m and n is maximum 8;

whereat a product mixture is obtained;

f) processing the product mixture from step e) to obtain the final product by - removing all volatiles, either directly or after separating the product mixture into residue and product solution,

so that a raw product is obtained,

- dissolving the raw product in a non-polar organic solvent,

- clearing the obtained solution via filtration, centrifugation or

sedimentation and

- evaporating the solvent to dryness. The invention further comprises a Process for manufacturing of a compound as previously described (formula Ib), characterized in that the process comprises the following steps:

a) reacting an electrophile R’’’R’’’’PX with built-in auxiliary base and

phosphazene according to formula II,

,

in an aprotic organic solvent,

whereat the substituents R are

i) independently from each other chosen from the list comprising

the substituents methyl, ethyl, propyl, n-alkyl, iso-alkyl, sec-alkyl, tert-alkyl, cycloalkyl, phenyl, benzyl, aryl, heteroaryl, allyl, NR’ ₂ , NHR’, NR’R’’, N-pyrrolidino, N-piperidino, N-morpholino, N-tetraalkylguanidino (-N=C(NR ₂ ) ₂ ), N-phosphazenyl (-N=P(NR ₂ ) ₃ ), or

ii) two substituents R chemically bound to the same P form a chelate ring with each other derived from secondary 1,2- and 1,3-diamines such as derivatives of N,N’-dialkyl-1,2-ethanediamine

(-RN-CH ₂ CH ₂ -NR-), N,N’-dialkyl-1,3-propanediamine

(-RN-CH ₂ CH ₂ -CH ₂ -NR-), or N,N’-dialkyl-1,2-cyclohexanediamine, 1,4-butandiyl, 1,5-hexandiyl, whereat the substituents R’ are independently from each other

chosen from the list comprising

the substituents H, methyl, ethyl, propyl, n-alkyl, iso-alkyl, sec-alkyl, tert-alkyl, cycloalkyl, phenyl, benzyl, aryl, heteroaryl, allyl , OR, NR ₂ , pyrrolidino, piperidino;

and the substituents R’’ are independently from each other chosen from the list comprising the substituents methyl, ethyl, propyl, n-alkyl, iso-alkyl, sec-alkyl, tert-alkyl, cycloalkyl, phenyl, benzyl, aryl, heteroaryl, allyl, OR, NR ₂ , pyrrolidino, piperidino;

and X is chosen from the list comprising Cl, Br, I;

and R’’’ is NMe2 or NEt2 or pyrrolidyl or a combination of two of them; and R’’’’ is methyl, ethyl, propyl, n-alkyl, iso-alkyl, sec-alkyl, tert-alkyl, cycloalkyl, phenyl, benzyl, aryl;

index a has a value ranging from 1 through p, whereat p

is a positive integer numeral;

whereat the intermediate-product of this step is obtained as a

hydrohalogenide salt;

b) precipitating of the salt of the intermediate-product of step a) with a

weakly coordinating anion chosen from the list comprising the weakly coordinatin anions

tetrafluoridoborate, tetraphenylborate,

hexafluorophosphate, hexafluoroantimonate, hexafluoroarsenate, triflate, bistryiflylimide by dissolving the intermediate product

hydrohalogenide salt of

step a) in a minimum amount of water, thus creating a saturated or nearly saturated aqueous solution, adding a saturated or nearly saturated solution of the respective sodium salt of the weakly coordinating anion under stirring,

separating the precipitated salt of the intermediate-product of step a) with the weakly coordinating anion

being formed, rinsing it and drying it;

c) deprotonating of the salt with the weakly coordinating anion from

step b) by reacting it with

a metal amide within an organic solvent to the P(III) Brønsted or

Lewis superbase, obtaining a suspension containing the P(III) Brønsted or Lewis superbase;

d) separating the suspension from step c) into the organic solution of the P(III) Brønsted or Lewis superbase and the residue;

e) reacting the P(III) Brønsted or Lewis superbase solution from step d) or the suspension containing the P(III) Brønsted or Lewis superbase from step c) with a metal or semi-metal complex of formula MLmXn whereat - the metal or semi-metal M is chosen from the list comprising the metals resp. semi-metals

Fe, Co, Ni, Ru, Rh, Pd, Os, Ir, Pt, Sc, Y, La, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Mn, Re, Cu, Ag, Au, Zn, Cd, Hg, Al, Ga, In, Tl, Si, Ge, Sn, Pb, As, Sb, Bi, Te, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, whereat the oxidation number of metal or semi-metal M may be 0, +1, +2, +3, +4, +5, +6, +7 or +8 as far as the theory of oxidation number allows the oxidation number of the certain metal or semi- metal M to accept the specific value;

- the ligands L are independently from each other chosen from the list comprising NO, CO, PR’’’’3, NR’’’’3, R’’’’NH ₂ , NH3, H ₂ O, R’’’’OH, R’’’’OR’’’’, alkene, alkyne, arene, carbenes such as CHPh or

N-heterocyclic carbenes (NHC), whereat substituents R’’’’ are independently chosen from the list comprising the substituents methyl, ethyl, propyl,

n-alkyl, iso-alkyl, sec-alkyl, tert-alkyl,

cycloalkyl, phenyl, benzyl, aryl;

- the ligands X are independently from each other chosen from the list of formally anionic ligands comprising H, F, Cl, Br, I, OH, OR, NR ₂ , CN, CH ₃ , C ₂ H ₅ , substituted or unsubstituted alkyl ligands, H, C ₆ H ₅ , substituted or unsubstituted aryl ligands, C ₅ H ₅ , substituted or unsubstituted cyclopentadienyl ligands, C ₃ H ₅ , substituted or unsubstituted allyl ligands, C ₂ H ₃ , substituted or unsubstituted vinyl ligands, CCMe, substituted or unsubstituted 1-alkinyl ligands, COMe, substituted or unsubstituted acyl ligands,

SiR ₃ , substituted or unsubstituted silyl ligands, formally dianionic ligands O (oxo), NR (organoimido), CHR, CR ₂ (alkylidene),

O ₂ (peroxo), formally trianionic: N (nitrido), CR (alkylidyne);

- index m is an integer numeral having a value of 0, 1, 2, 3, 4, 5 or 6 and index n is an integer numeral having a value of 0, 1, 2, 3, 4, 5 or 6 whereat the sum of indexes m and n is maximum 8;

whereat a product mixture is obtained;

f) processing the product mixture from step e) to obtain the final product by - removing all volatiles, either directly or after separating the product mixture into residue and product solution,

so that a raw product is obtained,

- dissolving the raw product in a non-polar organic solvent,

- clearing the obtained solution via filtration, centrifugation or

sedimentation and

- evaporating the solvent to dryness. The invention further comprises a Process for manufacturing of a compound as previously described (formula Ic), characterized in that the process comprises the following steps:

a) reacting an electrophile R’’’’ ₂ PX or an electrophile R’’’’ ₂ PR’’’ with built-in auxiliary base and phosphazene according to formula II,

in an aprotic organic solvent,

whereat the substituents R are

i) independently from each other chosen from the list comprising

the substituents methyl, ethyl, propyl, n-alkyl, iso-alkyl, sec-alkyl, tert-alkyl, cycloalkyl, phenyl, benzyl, aryl, heteroaryl, allyl, NR’ ₂ , NHR’, NR’R’’, N-pyrrolidino, N-piperidino, N-morpholino, N-tetraalkylguanidino (-N=C(NR ₂ ) ₂ ), N-phosphazenyl (-N=P(NR ₂ ) ₃ ), or

ii) two substituents R chemically bound to the same P form a chelate ring with each other derived from secondary 1,2- and 1,3-diamines such as derivatives of N,N’-dialkyl-1,2-ethanediamine

(-RN-CH ₂ CH ₂ -NR-), N,N’-dialkyl-1,3-propanediamine

(-RN-CH ₂ CH ₂ -CH ₂ -NR-), or N,N’-dialkyl-1,2-cyclohexanediamine, 1,4-butandiyl, 1,5-hexandiyl,

whereat the substituents R’ are independently from each other

chosen from the list comprising

the substituents H, methyl, ethyl, propyl, n-alkyl, iso-alkyl, sec-alkyl, tert-alkyl, cycloalkyl, phenyl, benzyl, aryl, heteroaryl, allyl , OR, NR ₂ , pyrrolidino, piperidino;

and the substituents R’’ are independently from each other chosen from the list comprising the substituents methyl, ethyl, propyl, n-alkyl, iso-alkyl, sec-alkyl, tert-alkyl, cycloalkyl, phenyl, benzyl, aryl, heteroaryl, allyl, OR, NR ₂ , pyrrolidino, piperidino;

and X is chosen from the list comprising Cl, Br, I;

and R’’’ is NMe ₂ or NEt ₂ or pyrrolidyl or a combination of two of them; and substituents R’’’’ are independently from each other methyl, ethyl, propyl, n-alkyl, iso-alkyl, sec-alkyl, tert-alkyl, cycloalkyl, phenyl, benzyl, aryl;

index a has a value ranging from 1 through p, whereat p

is a positive integer numeral;

whereat the intermediate-product of this step is obtained as a

hydrohalogenide salt;

b) precipitating of the salt of the intermediate-product of step a) with a

weakly coordinating anion chosen from the list comprising the weakly coordinatin anions

tetrafluoridoborate, tetraphenylborate,

hexafluorophosphate, hexafluoroantimonate, hexafluoroarsenate, triflate, bistryiflylimide by dissolving the intermediate product

hydrohalogenide salt of

step a) in a minimum amount of water, thus creating a saturated or nearly saturated aqueous solution, adding a saturated or nearly saturated solution of the respective sodium salt of the weakly coordinating anion under stirring,

separating the precipitated salt of the intermediate-product of step a) with the weakly coordinating anion

being formed, rinsing it and drying it;

c) deprotonating of the salt with the weakly coordinating anion from

step b) by reacting it with a metal amide within an organic solvent to the P(III) Brønsted or

Lewis superbase, obtaining a suspension containing the P(III) Brønsted or Lewis superbase;

d) separating the suspension from step c) into the organic solution of the P(III) Brønsted or Lewis superbase and the residue;

e) reacting the P(III) Brønsted or Lewis superbase solution from step d) or the suspension containing the P(III) Brønsted or Lewis superbase from step c) with a metal or semi-metal complex of formula ML _m X _n whereat - the metal or semi-metal M is chosen from the list comprising the metals resp. semi-metals

Fe, Co, Ni, Ru, Rh, Pd, Os, Ir, Pt, Sc, Y, La, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Mn, Re, Cu, Ag, Au, Zn, Cd, Hg, Al, Ga, In, Tl, Si, Ge, Sn, Pb, As, Sb, Bi, Te, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, whereat the oxidation number of metal or semi-metal M may be 0, +1, +2, +3, +4, +5, +6, +7 or +8 as far as the theory of oxidation number allows the oxidation number of the certain metal or semi- metal M to accept the specific value;

- the ligands L are independently from each other chosen from the list comprising NO, CO, PR’’’’ ₃ , NR’’’’ ₃ , R’’’’NH ₂ , NH ₃ , H ₂ O, R’’’’OH, R’’’’OR’’’’, alkene, alkyne, arene, carbenes such as CHPh or

N-heterocyclic carbenes (NHC), whereat substituents R’’’’ are independently chosen from the list comprising the substituents methyl, ethyl, propyl,

n-alkyl, iso-alkyl, sec-alkyl, tert-alkyl,

cycloalkyl, phenyl, benzyl, aryl;

- the ligands X are independently from each other chosen from the list of formally anionic ligands comprising H, F, Cl, Br, I, OH, OR, NR ₂ , CN, CH ₃ , C ₂ H ₅ , substituted or unsubstituted alkyl ligands, H, C ₆ H ₅ , substituted or unsubstituted aryl ligands, C ₅ H ₅ , substituted or unsubstituted cyclopentadienyl ligands, C ₃ H ₅ , substituted or unsubstituted allyl ligands, C ₂ H ₃ , substituted or unsubstituted vinyl ligands, CCMe, substituted or unsubstituted 1-alkinyl ligands, COMe, substituted or unsubstituted acyl ligands,

SiR3, substituted or unsubstituted silyl ligands, formally dianionic ligands O (oxo), NR (organoimido), CHR, CR ₂ (alkylidene), O ₂ (peroxo), formally trianionic: N (nitrido), CR (alkylidyne);

- index m is an integer numeral having a value of 0, 1, 2, 3, 4, 5 or 6

and index n is an integer numeral having a value of 0, 1, 2, 3, 4, 5 or

6 whereat the sum of indexes m and n is maximum 8;

whereat a product mixture is obtained;

f) processing the product mixture from step e) to obtain the final product by

- removing all volatiles, either directly or after separating the product

mixture into residue and product solution,

so that a raw product is obtained,

- dissolving the raw product in a non-polar organic solvent,

- clearing the obtained solution via filtration, centrifugation or

sedimentation and

- evaporating the solvent to dryness. The invention further comprises the usage of a compound according to one of the previous descriptions (formula Ia, Ib, Ic) as catalyst for a chemical reaction. The invention further comprises a Process for manufacturing of a compound according to formula IIIa:

,

The Process for manufacturing of a compound according to formula IIIa is characterized in that the process comprises the following steps:

a) reacting an electrophile R’’’ ₂ PX with built-in auxiliary base and

phosphazene according to formula II,

in an aprotic organic solvent,

whereat the substituents R are

i) independently from each other chosen from the list comprising

the substituents methyl, ethyl, propyl, n-alkyl, iso-alkyl, sec-alkyl, tert-alkyl, cycloalkyl, phenyl, benzyl, aryl, heteroaryl, allyl, NR’2, NHR’, NR’R’’, N-pyrrolidino, N-piperidino, N-morpholino, N-tetraalkylguanidino (-N=C(NR ₂ ) ₂ ), N-phosphazenyl (-N=P(NR ₂ ) ₃ ), or

ii) two substituents R chemically bound to the same P form a chelate ring with each other derived from secondary 1,2- and 1,3-diamines such as derivatives of N,N’-dialkyl-1,2-ethanediamine

(-RN-CH ₂ CH ₂ -NR-), N,N’-dialkyl-1,3-propanediamine

(-RN-CH ₂ CH ₂ -CH ₂ -NR-), or N,N’-dialkyl-1,2-cyclohexanediamine, 1,4-butandiyl, 1,5-hexandiyl,

whereat the substituents R’ are independently from each other

chosen from the list comprising

the substituents H, methyl, ethyl, propyl, n-alkyl, iso-alkyl, sec-alkyl, tert-alkyl, cycloalkyl, phenyl, benzyl, aryl, heteroaryl, allyl , OR, NR ₂ , pyrrolidino, piperidino;

and the substituents R’’ are independently from each other chosen from the list comprising the substituents methyl, ethyl, propyl, n-alkyl, iso-alkyl, sec-alkyl, tert-alkyl, cycloalkyl, phenyl, benzyl, aryl, heteroaryl, allyl, OR, NR ₂ , pyrrolidino, piperidino;

and X is chosen from the list comprising Cl, Br, I;

and R’’’ is NMe ₂ or NEt ₂ or pyrrolidyl or a combination of two of them; index a has a value ranging from 1 through p, whereat p

is a positive integer numeral;

whereat the intermediate-product of this step is obtained as a

hydrohalogenide salt;

b) precipitating of the salt of the intermediate-product of step a) with a weakly coordinating anion chosen from the list comprising the weakly coordinatin anions

tetrafluoridoborate, tetraphenylborate,

hexafluorophosphate, hexafluoroantimonate, hexafluoroarsenate, triflate, bistryiflylimide by dissolving the intermediate product

hydrohalogenide salt of

step a) in a minimum amount of water, thus creating a saturated or nearly saturated aqueous solution, adding a saturated or nearly saturated solution of the respective sodium salt of the weakly coordinating anion under stirring,

separating the precipitated salt of the intermediate-product of step a) with the weakly coordinating anion

being formed, rinsing it and drying it;

c) deprotonating of the salt with the weakly coordinating anion from

step b) by reacting it with

a metal amide within an organic solvent to the P(III) Brønsted or

Lewis superbase, obtaining a suspension containing the P(III) Brønsted or Lewis superbase;

d) separating the suspension from step c) into the organic solution of the P(III) Brønsted or Lewis superbase and the residue;

e) processing the organic solution of the P(III) Brønsted or Lewis superbase from step d) to obtain the final product by

- removing all volatiles,

so that a raw product is obtained,

- dissolving the raw product in a non-polar organic solvent,

- clearing the obtained solution via filtration, centrifugation or

sedimentation and

- evaporating the solvent to dryness. The invention further comprises a Process for manufacturing of a compound according to formula IIIb:

,

The Process for manufacturing of a compound according to formula IIIb is characterized in that the process comprises the following steps:

a) reacting an electrophile R’’’R’’’’PX with built-in auxiliary base and

phosphazene according to formula II,

,

in an aprotic organic solvent,

whereat the substituents R are

i) independently from each other chosen from the list comprising

the substituents methyl, ethyl, propyl, n-alkyl, iso-alkyl, sec-alkyl, tert-alkyl, cycloalkyl, phenyl, benzyl, aryl, heteroaryl, allyl,

NR’ ₂ , NHR’, NR’R’’, N-pyrrolidino, N-piperidino, N-morpholino, N-tetraalkylguanidino (-N=C(NR ₂ ) ₂ ), N-phosphazenyl (-N=P(NR ₂ ) ₃ ), or

ii) two substituents R chemically bound to the same P form a chelate

ring with each other derived from secondary 1,2- and 1,3-diamines such as derivatives of N,N’-dialkyl-1,2-ethanediamine

(-RN-CH ₂ CH ₂ -NR-), N,N’-dialkyl-1,3-propanediamine

(-RN-CH ₂ CH ₂ -CH ₂ -NR-), or N,N’-dialkyl-1,2-cyclohexanediamine, 1,4-butandiyl, 1,5-hexandiyl,

whereat the substituents R’ are independently from each other

chosen from the list comprising

the substituents H, methyl, ethyl, propyl, n-alkyl, iso-alkyl, sec-alkyl, tert-alkyl, cycloalkyl, phenyl, benzyl, aryl, heteroaryl, allyl , OR, NR ₂ , pyrrolidino, piperidino;

and the substituents R’’ are independently from each other chosen from the list comprising the substituents methyl, ethyl, propyl, n-alkyl, iso-alkyl, sec-alkyl, tert-alkyl, cycloalkyl, phenyl, benzyl, aryl, heteroaryl, allyl, OR, NR ₂ , pyrrolidino, piperidino;

and X is chosen from the list comprising Cl, Br, I;

and R’’’ is NMe ₂ or NEt ₂ or pyrrolidyl or a combination of two of them; and R’’’’ is methyl, ethyl, propyl, n-alkyl, iso-alkyl, sec-alkyl, tert-alkyl, cycloalkyl, phenyl, benzyl, aryl;

index a has a value ranging from 1 through p, whereat p

is a positive integer numeral;

whereat the intermediate-product of this step is obtained as a

hydrohalogenide salt;

b) precipitating of the salt of the intermediate-product of step a) with a

weakly coordinating anion chosen from the list comprising the weakly coordinatin anions

tetrafluoridoborate, tetraphenylborate,

hexafluorophosphate, hexafluoroantimonate, hexafluoroarsenate, triflate, bistryiflylimide by dissolving the intermediate product

hydrohalogenide salt of

step a) in a minimum amount of water, thus creating a saturated or nearly saturated aqueous solution, adding a saturated or nearly saturated solution of the respective sodium salt of the weakly coordinating anion under stirring,

separating the precipitated salt of the intermediate-product of step a) with the weakly coordinating anion

being formed, rinsing it and drying it;

c) deprotonating of the salt with the weakly coordinating anion from

step b) by reacting it with

a metal amide within an organic solvent to the P(III) Brønsted or

Lewis superbase, obtaining a suspension containing the P(III) Brønsted or Lewis superbase;

d) separating the suspension from step c) into the organic solution of the P(III) Brønsted or Lewis superbase and the residue; e) processing the organic solution of the P(III) Brønsted or Lewis superbase from step d) to obtain the final product by

- removing all volatiles,

so that a raw product is obtained,

- dissolving the raw product in a non-polar organic solvent,

- clearing the obtained solution via filtration, centrifugation or

sedimentation and

- evaporating the solvent to dryness. The invention further comprises a Process for manufacturing of a compound according to formula IIIc:

,

The Process for manufacturing of a compound according to formula IIIc is characterized in that the process comprises the following steps:

a) reacting an electrophile R’’’’ ₂ PX or an electrophile R’’’’ ₂ PR’’’ with built-in

auxiliary base and phosphazene according to formula II,

,

in an aprotic organic solvent,

whereat the substituents R are

i) independently from each other chosen from the list comprising

the substituents methyl, ethyl, propyl, n-alkyl, iso-alkyl, sec-alkyl, tert-alkyl, cycloalkyl, phenyl, benzyl, aryl, heteroaryl, allyl,

NR’ ₂ , NHR’, NR’R’’, N-pyrrolidino, N-piperidino, N-morpholino, N-tetraalkylguanidino (-N=C(NR ₂ ) ₂ ), N-phosphazenyl (-N=P(NR ₂ ) ₃ ), or

ii) two substituents R chemically bound to the same P form a chelate ring with each other derived from secondary 1,2- and 1,3-diamines such as derivatives of N,N’-dialkyl-1,2-ethanediamine

(-RN-CH ₂ CH ₂ -NR-), N,N’-dialkyl-1,3-propanediamine

(-RN-CH ₂ CH ₂ -CH ₂ -NR-), or N,N’-dialkyl-1,2-cyclohexanediamine, 1,4-butandiyl, 1,5-hexandiyl,

whereat the substituents R’ are independently from each other

chosen from the list comprising

the substituents H, methyl, ethyl, propyl, n-alkyl, iso-alkyl, sec-alkyl, tert-alkyl, cycloalkyl, phenyl, benzyl, aryl, heteroaryl, allyl , OR, NR ₂ , pyrrolidino, piperidino;

and the substituents R’’ are independently from each other chosen from the list comprising the substituents methyl, ethyl, propyl, n-alkyl, iso-alkyl, sec-alkyl, tert-alkyl, cycloalkyl, phenyl, benzyl, aryl, heteroaryl, allyl, OR, NR ₂ , pyrrolidino, piperidino;

and X is chosen from the list comprising Cl, Br, I;

and R’’’ is NMe ₂ or NEt ₂ or pyrrolidyl or a combination of two of them; and substituents R’’’’ are independently from each other methyl, ethyl, propyl, n-alkyl, iso-alkyl, sec-alkyl, tert-alkyl, cycloalkyl, phenyl, benzyl, aryl;

index a has a value ranging from 1 through p, whereat p

is a positive integer numeral;

whereat the intermediate-product of this step is obtained as a

hydrohalogenide salt;

b) precipitating of the salt of the intermediate-product of step a) with a

weakly coordinating anion chosen from the list comprising the weakly coordinatin anions

tetrafluoridoborate, tetraphenylborate,

hexafluorophosphate, hexafluoroantimonate, hexafluoroarsenate, triflate, bistryiflylimide by dissolving the intermediate product

hydrohalogenide salt of

step a) in a minimum amount of water, thus creating a saturated or nearly saturated aqueous solution, adding a saturated or nearly saturated solution of the respective sodium salt of the weakly coordinating anion under stirring,

separating the precipitated salt of the intermediate-product of step a) with the weakly coordinating anion

being formed, rinsing it and drying it;

c) deprotonating of the salt with the weakly coordinating anion from

step b) by reacting it with

a metal amide within an organic solvent to the P(III) Brønsted or

Lewis superbase, obtaining a suspension containing the P(III) Brønsted or Lewis superbase;

d) separating the suspension from step c) into the organic solution of the

P(III) Brønsted or Lewis superbase and the residue;

e) processing the organic solution of the P(III) Brønsted or Lewis superbase

from step d) to obtain the final product by

- removing all volatiles,

so that a raw product is obtained,

- dissolving the raw product in a non-polar organic solvent,

- clearing the obtained solution via filtration, centrifugation or

sedimentation and

- evaporating the solvent to dryness. As is obvious to the person skilled in the art, all of the above mentioned lists of substitutents and ligands as well as the lists of weakly coordination anions (“WCA”) are not intended to confine the scope of the invention. They are given only by way of example. There are many more items of those lists conceivable by the person skilled in the art which are also encompassed by the scope of the invention.

Description of Drawings

Figure 1. Molecular structures of 2∙HBPh ₄ , 3∙HBPh ₄ , 7∙HBF ₄ , and 4∙HBF ₄ . Carbon bonded hydrogen atoms and the anion omitted for clarity, ellipsoids at 50% probability, in case of disorder only the major component is displayed. Selected bond length [Å] and angles [°]: 2∙HBPh ₄ : P2 ₁ /n P1-N11.5941(13), P1-N51.5896(14), P1-N91.6074(14), N1- P2 1.5560(13), N5-P3 1.5560(13), N9-P4 1.5632(13), P1-N1-P2 136.90(9), P1-N5-P3 137.37(9), P1-N9-P4131.57(9).3∙HBPh ₄ : P1¯ P1-N11.5980(14), P1-N51.6021(14), P1- N9 1.5956(14), N1-P2 1.5676(14), N5-P3 1.5786(14), N9-P4 1.5618(13), P1-N1-P2 133.00(9), P1-N5-P3129.02(9), P1-N9-P4134.02(10).7∙HBF ₄ : P2 ₁ /c P1-N11.5999(12), P1-N5 1.5902(12), P1-N9 1.5884(12), N1-P2 1.5660(12), N5-P3 1.5408(12), N10-P5 1.5674(13), N9-P4 1.5798(12), P4-N10 1.5881(12), P4-N11 1.6713(13), P4-N12 1.6572(12), P1-N1-P2137.46(8), P1-N5-P3157.67(9), P1-N9-P4133.27(8), P4-N10-P5 132.26(8), N9-P4-N10120.09(7), N11-P4-N12111.28(7).4∙HBF ₄ : P1¯ P1-N11.6083(16), P1-N8 1.5901(16), P1-N15 1.5931(16), P2-N2 1.5961(16), P4-N9 1.5981(16), P6-N16 1.5924(17), N1-P21.5737(16), N8-P41.5733(16), N15-P61.5638(16), N2-P31.5679(16), N9-P51.5628(16), N16-P71.5485(17), P1-N1-P2129.13(10), P1-N8-P4136.87(11), P1- N15-P6134.52(11), P2-N2-P3133.37(10), P4-N9-P5133.47(11), P6-N16-P7145.36(11). Figure 2. Figure S1: ³¹ P{ ¹ H} NMR spectrum of the reaction mixture of 4∙HBF ₄ and NaNH2 (THF, 300 K, 101.3 MHz).

* starting material.

Figure 3. Figure S2: ³¹ P{ ¹ H} NMR spectrum of the reaction mixture of 4∙HBF ₄ and Kpyrr. (toluene, 300 K, 101.3 MHz).

Figure 4. Molecular structures of 15 and 17. Hydrogen atoms omitted for clarity, ellipsoids at 50% probability, in case of disorder only the major component is displayed. Selected bond length [Å] and angles [°]: 15: P2 ₁ 2 ₁ 2 ₁ P1-Ni1 2.2640(7), P1-N1 1.657(2), P1-N5 1.666(2), P1-N9 1.648(2), N1-P2 1.536(2), N5-P3 1.540(2), N10-P5 1.548(2), N9-P4 1.554(2), P4-N10 1.608(2), P4-N11 1.684(2), P4-N12 1.666(2), P1-N1-P2 139.92(15), P1-N5-P3 138.36(15), P1-N9-P4 140.08(14), P4-N10-P5 138.83(15), N9-P4-N10 114.92(12), N11-P4-N12 103.10(12). 17: Pa3¯ P1-Pd1 2.3123(19), P3-Pd1 2.2129(18), P1-N11.653(3), N1-P21.544(3), P1-N1-P2132.6(2), N1-P1-P3-C7167.4(2).