PELLEGRIN YANN (FR)
BARON THIBAUT (FR)
JACQUEMIN DENIS (FR)
SAUVAGE FRÉDERIC (FR)
NAIM WAAD (FR)
UNIV NANTES (FR)
UNIV PICARDIE (FR)
| EP2272849A1 | 2011-01-12 |
NATURE ENERGY, vol. 2, November 2017 (2017-11-01), pages 849 - 860
ADV. MATER., vol. 29, 2017, pages 1700192
LEE, K.UM, H.-D.CHOI, D.PARK, J.KIM, N.KIM, H.SEO, K.: "The Development of Transparent Photovoltaics", CELL REPORTS PHYSICAL SCIENCE, vol. 1, 2020, pages 100143
ACS APPL. ENERGY MATER., vol. 2, 2019, pages 3972 - 3978
SOLAR ENERGY MATERIALS AND SOLAR CELLS, 2019, pages 196
ADV. ENERGY MATER., vol. 5, 2015, pages 1500486
ADV. ENERGY MATER., vol. 4, 2014, pages 1301966
CHEM. SOC. REV., vol. 45, 2016, pages 9
EUR. J. INORG. CHEM., 2020, pages 899 - 917
ACS OMEGA, vol. 4, 2019, pages 14272 - 14283
J. PHYS. CHEM. C, vol. 122, 2018, pages 495
| CLAIMS 1. A compound having the following formula (I): wherein: ● Ar is selected from the group consisting of: o a phenyl group; and o a phenyl group substituted with at least one substituent L selected from the group consisting of: ▪ (C1-C16)alkyl groups; ▪ (C1-C16)alkoxy groups; and ▪ (C1-C16)thioalkyl groups; ● Y is selected from the group consisting of: o a phenylene radical; and o a thiophenylene radical; o a furanylene radical; and ● W is a phenyl group comprising at least one substituent Z, in particular one, two or three substituents Z, wherein Z is selected from the group consisting of: 25 ▪ (C1-C12)alkyl groups; ▪ (C1-C12)alkoxy groups; and ▪ di((C1-C12)alkyl)amino groups; ● R1 is H; ● R2 is an anchoring group selected from the group consisting of: o a -COOH group; o a -C(=O)-NH(OH) group; o a -CH=C(CN)(COOH) group; and o a -PO3H2 group; ● R3 is selected from the group consisting of: o H; o an anchoring group selected from the group consisting of: ● a -COOH group; ▪ a -C(=O)-NH(OH) group; ▪ a -CH=C(CN)(COOH) group; and ▪ a -PO3H2 group; o (C1-C16)alkyl groups; o (C1-C16)alkoxy groups; o (C1-C16)thioalkyl groups; and o a group having the following formula (III): wherein R5 and R6, identical or different, are selected from the group consisting of: ▪ (C1-C16)alkyl groups; ▪ a group having the following formula (IV): R7 being a (C1-C16)alkyl group; ▪ a group having the following formula (V): R8 being a (C1-C16)alkyl group; ▪ a group having the following formula (VI): R9 being a (C1-C16)alkyl group; o a group having the following formula (III-1): wherein R’5 and R’6, identical or different, preferably identical, are a group having the following formula (VI-1): ( ) R’9 being a (C1-C16)alkyl group; ● R4 is selected from the group consisting of: o H; o (C1-C16)alkyl groups; o (C1-C16)alkoxy groups; o (C1-C16)thioalkyl groups; and o a group having the following formula (VII): wherein R10 and R11, identical or different, are selected from the group consisting of: ▪ (C1-C16)alkyl groups; ▪ a group having the following formula (VIII): R12 being a (C1-C16)alkyl group; ▪ a group having the following formula (IX): R13 being a (C1-C16)alkyl group; ▪ a group having the following formula (X): R14 being a (C1-C16)alkyl group. 2. The compound having the formula (I) of claim 1, wherein Ar is selected from the group consisting of: ● a phenyl group; ● a substituted phenyl group comprising one substituent in ortho, meta or 20 para position, having the following formula (1): L being as defined in claim 1; ● a substituted phenyl group having the following formula (2): wherein - L1 is selected from the group consisting of: ▪ (C1-C16)alkyl groups; ▪ (C1-C16)alkoxy groups; and ▪ (C1-C16)thioalkyl groups; - L2 is H and L3 is selected from the group consisting of: ▪ (C1-C16)alkyl groups; ▪ (C1-C16)alkoxy groups; and ▪ (C1-C16)thioalkyl groups; - or L3 is H and L2 is selected from the group consisting of: ▪ (C1-C16)alkyl groups; ▪ (C1-C16)alkoxy groups; and ▪ (C1-C16)thioalkyl groups; ● a substituted phenyl group having the following formula (3): wherein - L4 is selected from the group consisting of: ▪ (C1-C16)alkyl groups; ▪ (C1-C16)alkoxy groups; and ▪ (C1-C16)thioalkyl groups; - L5 is H and L6 is selected from the group consisting of: ▪ (C1-C16)alkyl groups; 25 ▪ (C1-C16)alkoxy groups; and ▪ (C1-C16)thioalkyl groups; - or L6 is H and L5 is selected from the group consisting of: ▪ (C1-C16)alkyl groups; ▪ (C1-C16)alkoxy groups; and ▪ (C1-C16)thioalkyl groups. 3. The compound having the formula (I) of claim 1 or 2, wherein Ar is selected from the group consisting of: ● a phenyl group; ● a substituted phenyl group having the formula (1) as defined in claim 2; ● a substituted phenyl group having the formula (2) as defined in claim 2, wherein: - L1 is as defined in claim 2; and - L2 is H and L3 is identical to L1 or L3 is H and L2 is identical to L1; and ● a substituted phenyl group having the formula (3) as defined in claim 2, wherein: - L4 is as defined in claim 2; and - L5 is H and L6 is identical to L4 or L6 is H and L5 is identical to L4. 4. The compound having the formula (I) of any one of claims 1 to 3, wherein Ar is a phenyl group, a p-tert-butylphenyl group or a phenyl group substituted with an alkoxy group. 5. A compound according to any one of claims 1 to 4, having the following formula (II): wherein Ar, R1, R2, R3, R4, and W are as defined in any one of claims 1 to 4. 25 6. A compound according to any one of claims 1 to 5, wherein W is a group having one of the below formulae (4) to (7): Z being as defined in claim 1. 7. A compound according to any one of claims 1 to 6, wherein R1 is H and R2 is an anchoring group as defined in claim 1, such as -COOH. 8. A compound according to any one of claims 1 to 7, wherein R1 and R4 are H, and R2 and R3 are anchoring groups as defined in claim 1. 9. A compound according to any one of claims 1 to 8, wherein R1 and R4 are H, and R2 and R3 are -COOH. 10. A compound according to any one of claims 1 to 9, having one of the following formulae: 11. The use of the compound of any one of claims 1 to 10 as a dye sensitizer. 12. A dye sensitized solar cell comprising at least one compound of any one of claims 1 to 10 as dye sensitizer. 13. The dye sensitized solar cell of claim 12, further comprising at least one further dye, said dye being identical to or different from a compound of any one of claims 1 to 10. 14. The use of the compound of any one of claims 1 to 10 as a dye sensitizer in dye-sensitized photocatalytic systems (DSPs) for hydrogen production, CO2 reduction, water oxidation, organic compounds activation, or degradation of pollutants. |
The present invention also relates to a compound as defined above, having the following formula (II): wherein Ar, R 1 , R 2 , R 3 , R 4 , and W are as defined above. According to an embodiment, in formula (I) or in formula (II) as defined above, W is a group having one of the below formulae (4) to (7): Z being as defined above. According to an embodiment, in formula (I) or in formula (II), R 1 is H and R 2 is an anchoring group as defined above in formula (I), such as -COOH. According to an embodiment, in formula (I) or in formula (II), R 1 is H and R 2 is -COOH. According to an embodiment, in formula (I) or in formula (II), R 1 and R 4 are H, and R 2 and R 3 are anchoring groups as defined above. According to an embodiment, in formula (I) or in formula (II), R 1 and R 4 are H, and R 2 and R 3 are -COOH. According to an embodiment, in formula (I) or in formula (II), R 1 and R 4 are H, and R 2 is -COOH and R 3 is a group of formula (VII) or (VII’). According to an embodiment, in formula (I) or in formula (II), R 1 and R 3 are H, and R 2 is -COOH and R 4 is a group of formula (VII). According to a preferred embodiment, the present invention relates to a compound having one of the following formulae:
The present invention also relates to the use of a compound of formula (I) as defined above as a dye sensitizer. The present invention also relates to a dye sensitized solar cell comprising at least one compound of formula (I) as defined above as dye sensitizer. The compounds of formula (I) as defined above have a low absorption in the visible range and thus can be used to prepare DSSC being transparent and colorless. The compounds according to the invention have a strong absorbance in the near infrared (NIR) and are also efficient as they have proved already a PCE of at least 4% under standard A.M.1.5G light conditions. The DSSCs cells prepared with the dyes according to the invention have a PCE of 4% (J sc = 15.6 mA/cm 2 , V oc = 430 mV, ff = 0.59) with an AVT which can be superior to 75%, which demonstrates the great potential of this new family of compounds. The sensitizers according to the invention are able to absorb little or not at all in the visible range, making them almost colorless for the naked eye. The sensitizer is integrated in the DSSC device by chemisorption to a large bandgap semi-conductor such as TiO 2 , ZnO, SnO 2 or their derivatives including doped materials, constituting the photo-active electrode. This is carried out by soaking the photo-anode in a solution with the dye solubilized containing deaggregating/coadsorbant agent. The nanoparticles of the large bandgap semi- conductor are deposited by screen-printing from a paste containing the nanoparticles followed by post-annealing treatment to remove the porogen. It leads to a porosity that can be modulated between 25 to 70 %. The transparent counter- electrode is based on glass transparent conducting oxide bearing low amount of electrocatalytic nanoparticles such as Pt, graphene or related materials, MXenes, sulfides to maintain high optical transparency. The liquid electrolyte is composed of a solvent or solvent-free ionic liquids containing additives such imidazolium or pyridinium-based molecules, alkali cations and the redox mediator such as iodine/iodide, tempo-derivatives, binary systems such as iodo-bromide or iodo- sulfide systems or organometallic complexes. The two electrodes are sealed together using a thermoplastic polymer heated under ambient or controlled atmosphere. Glass-frit sealing of devices is a second option to ensure high quality sealing and barrier to O 2 or water ingress. The electrolyte is injected by vacuum back-filling or by means of a peristatic pump flow through UV-drilled or sandblasting hole located at the counter-electrode side. This part is hermetically sealed either by a polymer or a glass-frit after electrolyte injection. An antireflecting coating can be applied to the two sides of the device using a ultra-thin layer of SiO 2 nanoparticles deposited by spin coating. The DSSC according to the invention may be used to prepare a transparent window which can be used for building-integrated, automobile-integrated, building applied PV or urban street equipment. It can be integrated as a transparent embodiment for nomadic electronics or on-screen applications. According to an embodiment, the dye sensitized solar cell of the invention further comprises at least one further dye, said dye being identical to or different from a compound of formula (I) according to the invention. As further dyes, the followings may be mentioned: Ru, Fe, Cu, Zn or Os-based coordination complexes, organic donor-π-acceptor molecules, polymethine, croconines or squaraine dyes. The present invention also relates to the use of a compound of formula (I) as defined above as a dye sensitizer in dye-sensitized photocatalytic systems (DSPs) for hydrogen production, CO 2 reduction, water oxidation, organic compounds activation or degradation of pollutants. A typical DSP is composed of a photosensitizer (PS) and a catalyst (CAT) which are both co-grafted onto n-type semiconductor (n-SC) nanoparticles (NPs), usually titanium dioxide (TiO 2 )(see Chem. Soc. Rev., 2016, 45, 9 and Eur. J. Inorg. Chem. 2020, 899–917). The operation principle of DSP shares many similarities with DSSC. Upon light irradiation, the PS absorbs photons and injects electrons in the conduction band (CB) of the n-SC, which acts as electron mediator between the PS and the CAT. Then, the reduced CAT performs the desired reaction ( H 2 production or CO 2 reduction). Finally, the oxidized PS (PS + ) is regenerated by an external sacrificial electron donor (SD). Many similar sensitizers of DSSC have been successfully implemented in DSP (see Chem. Soc. Rev., 2016, 45, 9 and Eur. J. Inorg. Chem. 2020, 899–917), but very few effectively exploit NIR window to produce fuels (ACS Omega 2019, 4, 14272−14283; ACS Appl. Energy Mater.2019, 2, 448−458; and J. Phys. Chem. C 2018, 122, 495). Owing to the high efficiency of DPP dyes in DSC, it is reasonable to expect significant efficiency of the latter dyes in DSPs. For example, the described compounds in this patent can be certainly co- immobilized on TiO 2 NPs with a molecular or inorganic catalyst for CO 2 reduction of H 2 production. FIGURES Figure 1: (J-V) curve measured under A.M.1.5G conditions upon optimized conditions and electrolyte formulation with DSSC including S1, S5 or S7 dyes. Figure 2: Absorption spectra of S1, S3, S4, S5 and S7 recorded in DMF solution. Figure 3: Emission spectra of S1, S3, S4, S5 and S7 recorded in DMF solution. Figure 4: Streak image and variation of absorbance for the ground-state and radical cation of the dye (S1) in DSSC obtained by ps-pump probe transient absorption spectroscopy. Figure 5: Quantity of H 2 produced (left) and turnover number (right) as a function of the irradiation time.
EXAMPLES
Example 1: Preparation of sensitizer S1
1. Synthesis of intermediate compound DPP-1
1.1. Preparation of DPP-1” A catalytic amount of FeCl 3 was dissolved in t-amylalcohol (20 mL), small cubes of solid sodium were added (1 g, 44 mmol, 5 eq) and the mixture was heated at 90°C for 1h. A suspension of 4-iodobenzonitrile (5 g, 22 mmol, 2,5 eq) in t- amylacohol (12.5 mL) was added, followed by a dropwise addition of diethyl succinate (1.52 g, 8.7 mmol), the resulting red solution was heated at 90°C. The mixture was cooled at room temperature and acetic acid (5 mL), was added dropwise under vigorous stirring. After complete addition the red slurry was stirred at 110°C for 30 minutes and then cooled at room temperature, the resulting precipitate was recovered by filtration and washed with water and methanol to afford the desired compound as a dark powder (1.5 g, 37%). Due to its high insolubility in common organic solvents, DPP-1’’ was used without further purification. 1.2. Preparation of DPP-1’ Under argon atmosphere, DPP-1’’ (1.5g, 2.8 mmol) and DMAP (0.17 g, 1.4 mmol, 0.5 eq) were dissolved in dry THF (80mL) and stirred 30 minutes at room temperature. Di-tert-butyl dicarbonate (1.5 g, 6.9 mmol, 2.5 eq) dissolved in 20mL of dry THF was added dropwise to the reaction mixture. The reaction was stirred overnight at room temperature. The solution was quenched with water, extracted three times with ethyl acetate and the organic layer was dried over magnesium sulfate. Solvents were removed under reduce pressure at 25°C to afford the desired compound as a yellow solid (2.06 g, 100%). MW (g.mol -1 ): 740.33 NMR ( 1 H, CDCl 3 , 400 MHz), δ (ppm): 7.83 (d, 3 J=8.63 Hz, 4H), 7.46 (d, 3 J=8.65 Hz, 4H), 1.45 (s, 18H) NMR ( 13 C, CDCl 3 , 100 MHz), δ (ppm): 159.0, 147.9, 145.4, 137.6, 137.5, 129.7, 127.5, 112.6, 98.5, 85.7, 27.5 MS (ASAP-) m/z: 739.99 1.3. Preparation of boronic ester 1 In a sealable tube, 1-Bromo-3,5-di-tert-butylbenzene 4 (2g, 7.4mmol, bis(pinacolato)diboron (2.07 g, 8.2 mmol, 1.1 eq), potassium acetate (2.19 g, 22.3 mmol, 3 eq) and Pd(dppf)Cl 2 (0,27 g, 0.37 mmol, 0.05 eq) were placed under argon atmosphere and dissolved in dry DMF (40mL). The reaction mixture was heated overnight at 80°C. The reaction was cooled to room temperature, quenched with water, extracted three times with ethyl acetate, dried over magnesium sulfate and solvents were removed under reduce pressure. The crude was purified by column chromatography using CH 2 Cl 2 /petroleum ether (2/8) as eluent to afford the final product as white crystals (2.12 g, 90%). MW (g.mol -1 ): 316.29 NMR ( 1 H, CDCl 3 , 400 MHz), δ (ppm): 7.66 (d, 4 J=2.03 Hz, 2H), 7.54 (t, 4J=2.07 Hz, 1H), 1.35 (s, 18H), 1.34 (s, 12H) 1.4. Preparation of DPP-1 In a sealable tube, DPP-1’ (0.3 g, 0.41 mmol), boronic ester 1 (0.384 g, 1.22 20 mmol, 3 eq), and K 2 CO 3 (0.28 g, 2.03 mmol, 5eq) were placed under argon atmosphere and dissolved in THF (20mL) and water (6mL). The solution was degassed 30 minutes under argon in an ultrasonic bath and Pd(PPh3)4 (0.094 g, 0.081 mmol, 0.2 eq) was added. The reaction mixture was heated overnight at 85°C. The reaction was cooled to room temperature, quenched with water, extracted 3 times with ethyl acetate, dried over magnesium sulfate and solvents are removed under reduce pressure. The crude was then heated 30 minutes at 180°C in the oven. After cooling to room temperature, the resulting solid was dissolved in THF and filtrate through celite. After solvents removal, the product was taken up in cyclohexane and filtrated through membrane to afford the desired compound as a red solid (0.193 g, 71%). MW (g.mol -1 ): 664.93. NMR ( 1 H, THF, 400 MHz) δ (ppm): 10.36 (s, 2H), 8.74 (d, 3 J=8.61 Hz, 4H), 8.00 (d, 3 J=8.74 Hz, 4H), 7.74 (d, 4 J=1.75 Hz, 4H), 7.68 (t, 4 J=1.75 Hz, 2H), 1.58 (s, 36H). NMR ( 13 C, THF, 100 MHz) δ (ppm): 162.2, 151.1, 144.9, 143.1, 139.5, 128.0, 127.3, 127.0, 121.8, 121.3, 111.5, 34.6, 30.8609. HRMS (ES-) m/z: [M-H]- calculated for C46H51N2O2: 663.3951; found: 663.3957. Δ=0.9ppm. 2. Preparation of intermediate compound p1 2.1. Preparation of compound p1’’ Methyl isonicotinate (25 g, 182 mmol) was dissolved in MeOH (250mL) and H 2 SO 4 (1mL) under argon atmsophere and heated at reflux. A solution of ammonium persulfate (75 g, 328 mmol, 1.8 eq) in water (150mL) was added dropwise and the reaction mixture was stirred overnight at reflux. After cooling to room temperature, the mixture was filtrated through filter paper and the filtrate was concentrated in vacuo to remove MeOH. The resulting solution was extracted 3 times with ethyl acetate, washed 3 times with water, the organic layer was dried over magnesium sulfate and solvents were removed under reduced pressure. The solid was purified by column chromatography using PE/AcOEt (4:6) as eluent to afford the desired compound as yellowish oil (4.16 g, 14%). MW (g.mol -1 ): 167.17 NMR ( 1 H, CDCl3, 400 MHz) δ (ppm): 8.66 (dd, 3 J= 5.02 Hz, 4 J=0.83 Hz, 1h), 7.84 (q, 4 J=2.31 Hz, 4 J=0.74 Hz, 1H), 7.72 (dt, 3 J=5.16 Hz, 4 J=0.76 Hz, 1h), 4.81 (s, 2H), 3.93 (s, 3H) HRMS (ES+) m/z: [M-H]- calculated for C8H10NO3: 168.0661; found: 168.0655. Δ=-3.6ppm. 2.2. Preparation of compound p1’ In a solution of SOCl 2 (50mL) at 0°C was added dropwise p1’’ (4.16 g, 24.9 mmol) dissolved in CHCl 3 (5mL). The reaction was stirred overnight at room temperature. CH 2 Cl 2 (100mL) was added and the solvent were removed under reduce pressure. This step was repeated until the excess of SOCl 2 was entirely removed. The resulting grey solid (4.6 g, 100%) was used in the next step without further purification. MW (g.mol -1 ): 185.61 NMR ( 1 H, CDCl3, 300 MHz) δ (ppm): 8.88 (d, 3 J=5.52 Hz, 1H), 8.38 (s, 1H), 8.18 (dd, 3 J=4.20 Hz, 4 J=1.44 Hz, 1h), 5.08 (s, 2H), 4.04 (s, 3H) 2.3. Preparation of compound p1 Under argon atmosphere, p1’ (2.5 g, 13.5 mmol) was dissolved in dry ACN (250mL) and stirred at room temperature. TMSCN (2.53 mL, 20.2 mmol, 1.5 eq) and TBAF (20.2 mL, 20.2 mmol, 1.5 eq) were added and the reaction mixture heated 30 minutes at reflux. Solvents were evaporated. The resulting solid was solubilized in AcOEt and washed 4 times with brine The organic layer was dried over magnesium sulfate and solvents were evaporated. A brown oil (2.29 g, 96%) was obtained without further purification. MW (g.mol -1 ): 176.18 NMR ( 1 H, CDCl3, 400 MHz) δ (ppm): 8.73 (dd, 3 J=5.03 Hz, 4 J=0.77 Hz, 1H), 7.96 (d, 4 J=0.55 Hz, 1H), 7.82 (dd, 3 J=4.23 Hz, 4 J=1.46 Hz, 1H), 4.01 (s, 2H), 3.97 (s, 3H) NMR ( 13 C, CDCl3, 100 MHz) δ (ppm): 164.9, 151.6, 150.8, 138.8, 122.4, 121.5, 116.4, 53.4, 52.9, 26.6, 24.1, 19.7, 13.6823 HRMS (ASAP-) m/z: [M-H]- calculated for C9H7N2O2: 175.0508; found: 175.0510. Δ=1.1ppm 3. Synthesis of intermediate compound PPcy DPP-1 (0.130 g, 0.196 mmol) and p1 (0.088 g, 0.049 mmol, 2.5 eq) were heated to reflux in absolute toluene under argon. Phosphoryl chloride (0.15 mL, 1.57 mmol, 8 eq) was then added. The reaction was monitored by thin-layer chromatography. As soon as DPP-1 was used up or the concentration of by- products increased, the reaction was quenched with water and extracted 3 times with ethyl acetate. The organic layer was dried over magnesium sulfate and solvents were evaporated. The crude product was treated with methanol in an ultrasonic bath. The solid was collected by filtration and washed with methanol until the filtrate was colorless to afford the desired compound as a green solid (0.13 g, 68%). MW (g.mol -1 ): 980.50. NMR ( 1 H, CDCl3, 300 MHz) δ (ppm): 13.54 (s, 2H), 8.61 (d, 3 J=5.22 Hz, 2H), 7.83 (s, 2H), 7.75 (d, 4 J=1.60 Hz, 8H), 7.50 (d, 4 J=1.91 Hz, 4H), 7.48 (d, 4 J=1.46 Hz, 2H), 7.46 (t, 4 J=1.81 Hz, 2H), 3.93 (s, 6H), 1.38 (s, 36H). NMR ( 13 C, CDCl3, 100 MHz) δ (ppm): 165.1, 156.2, 151.2, 148.3, 144.9, 143.5, 139.6, 130.5, 127.9, 126.6, 122.1, 121.7, 120.1, 117.6, 116.9, 52.6, 31.5. MS (ASAP-) m/z: [M]- calculated for C64H64N6O4S2: 980.4989; found: 980.5007. Δ=1.8ppm. 3. Synthesis of intermediate compound PPcy-2 Under argon atmosphere, PPcy (0.10 g, 0.102 mmol,) and N,N- diisopropylethylamine (0.20 mL, 1.02 mmol, 10 eq) were heated to reflux in dry dichloromethane. Chloro(diphenyl)borane (0.2 mL) was added dropwise and the mixture was heated to reflux for 10 min. The reaction mixture was quenched with water, extracted three times with dichloromethane and dried over MgSO 4 . After removing the solvent, the crude product was purified by column chromatography using DCM/EP (7:3) as eluent to afford the desired compound as a green solid (0.055 g, 41%). MW (g.mol -1 ): 1309.28 NMR ( 1 H, CDCl3, 300 MHz) δ (ppm): 7.89 (d, 3 J=6.61 Hz, 2H), 7.86 (d, 4 J=1.65 Hz, 2H), 7.35 (t, 4 J=1.42 Hz, 2H), 7.32 (d, 4 J=1.70 Hz, 4H), 7.16 (d, 4 J=1.73 Hz, 2H), 7.13 (s, 20H), 7.05 (d, 3 J=8.24 Hz, 4H), 6.81 (d, 3 J=8.2Hz, 4H), 3,81 (s, 6H), 1.39 (s, 36H). HRMS (ASAP-) m/z: [M]- calculated for C 88 H 82 10B 2 N 6 O 4 : 1306.6656; found: 1306.6689. Δ=2.5ppm. 4. Synthesis of S1 PPcy-2 (0.055, 0.042 mmol) was stirred at room temperature in THF (10mL). A solution of LiOH (0.020 g, 0.84 mmol, 20 eq) in water (2mL) was added dropwise in the reaction mixture and stirred 1h. Aqueous hydrochloric acid preparation (2M) is added slowly until pH=4. The remaining solution was extracted 3 times with ethyl acetate. After evaporation, the crude product was dissolved in DCM and EP was added. The resulting precipitate was collected by filtration and washed with EP to afford the desired compound as a dark green solid (0.044 g, 81%). MW (g.mol -1 ): 1281.23 NMR ( 1 H, CDCl3, 300 MHz) δ (ppm): 7.92 (d, 3 J=6.62 Hz, 2H), 7.90 (d, 4 J=1.68 Hz, 2H), 7.39 (t, 4 J=1.81 Hz, 2H), 7.33 (d, 4 J=1.75 Hz, 4H), 7.13 (m, 22H), 7.05 (d, 3 J=8.20 Hz, 4H), 6.81 (d, 3 J=8.23 Hz, 4H), 1.38 (s, 36H). HRMS (ASAP-) m/z: [M]- calculated for C 86 H 78 10 B 2 N 6 O 4 : 1278.6343; found: 1278.6353. Δ=0.8ppm. Example 2: Preparation of sensitizer S2 1. Preparation of intermediate compound PPcy-3 Under argon atmosphere, PPcy (0.030 g, 0.031 mmol,) and N,N- diisopropylethylamine (0.05 mL, 0.306 mmol, 10 eq) were heated to reflux in dry dichloromethane. Bis(4-(tert-butyl)phenyl)chloroborane (0.1 mL) was added dropwise and the mixture was heated to reflux for 10min. The reaction mixture was quenched with water, extracted three times with dichloromethane and dried over MgSO 4 . After removing the solvent, the crude product was purified by column chromatography using DCM/EP (7:3) as eluent to afford the desired compound as a green solid (0.022 g, 47%). MW (g.mol -1 ): 1532.91 NMR ( 1 H, CDCl3, 300 MHz) δ (ppm): 7.96 (d, 3 J=6.62 Hz, 2H), 7.86 (d, 4 J=1.20 Hz, 2H), 7.40 (m, 6H), 7.18 (dd, 3 J=6.36 Hz, 4 J=1.77Hz, 2H), 7.14 (d, 3 J=8.01 Hz, 12H), 7.07 (d, 3 J=8.28 Hz, 8H), 6.81 (d, 3 J=8.37 Hz, 4H), 3.79 (s, 6H), 1.37 (s, 36H), 1.25 (s, 36H) HRMS (ASAP+) m/z: [M-H]+ calculated for C 104 H115 10 B 2 N 6 O 4 : 1331.9239; found: 1531.9181. Δ=-3.8ppm. 2. Preparation of S2 PPcy-3 (0.020, 0.013 mmol) was stirred at room temperature in THF (5mL). A solution of LiOH (0.006 g, 0.260 mmol, 20 eq) in water (1mL) is added dropwise in the reaction mixture and stirred for 1h. Aqueous hydrochloric acid preparation (2M) is added slowly until pH=4. The remaining solution was extracted 3 times with ethyl acetate. After evaporation, the crude product was dissolved in DCM and EP was added. The resulting precipitate was collected by filtration and washed with EP to afford the desired compound as a dark green solid (0.015 g, 79%). MW (g.mol -1 ): 1505.66 NMR ( 1 H, CDCl3, 300 MHz) δ (ppm): 7.88 (s, 2H), 7.30 (s, 6H), 7.06 (d, 3 J=18 Hz, 20H), 6.73 (d, 3 J=7.40Hz, 4H), 1.29 (s, 36H), 1.26 (s, 36H) HRMS (ASAP-) m/z: [M]- calculated for C 102 H 110 N 6 O 4 10 B 2 : 1502.8847; found: 1502.8879. Δ=2.1ppm.
Example 3: Preparation of sensitizer S3
1. Synthesis of intermediate compound DPP-2
1.1. Preparation of DPP-2’” tBuOK (7.2 g, 64mmol, 3.5 eq) was dissolved in 40mL of t-amyl alcohol. After complete dissolution of the base at 105°C, thiophene-2-carbonitrile (5 g, 45.8 mmol, 3 eq) was then added to the reaction mixture and the solution was heated one hour at 105°C. A solution of diethylsuccinate (3.19 g, 18.3 mmol) in 20mL of t-amyl alcohol was added dropwise at reflux within one hour and left overnight. The mixture was cooled at room temperature and acetic acid (5 mL), was added dropwise under vigorous stirring. After complete addition the slurry was stirred at 110°C for 30 minutes and then cooled at room temperature, the resulting precipitate was recovered by filtration and washed with water and methanol to afford the desired compound as a dark powder (3.2 g, 57%). Due to its high insolubility in common organic solvents, DPP-2’’’ was used without further purification. 1.2. Preparation of DPP-2’’ Under argon atmosphere, DPP-2’’’ (1.5g, 4.99 mmol) and DMAP (0.31 g, 2.5 mmol, 0.5 eq) were dissolved in dry THF (80mL) and stirred 30 minutes at room temperature. Di-tert-butyl dicarbonate (2.72 g, 12.5 mmol, 2.5 eq) dissolved in 20mL of dry THF was added dropwise to the reaction mixture. The reaction was stirred overnight at room temperature. The solution was quenched with water, extracted three times with ethyl acetate and the organic layer was dried over magnesium sulfate. Solvents were removed under reduce pressure at 25°C to afford the desired compound as a dark brown solid (2.15 g, 86%). MW (g.mol -1 ): 500.58 NMR ( 1 H, CDCl 3 , 400 MHz), δ (ppm): 8.82 (dd, 3 J=3.82 Hz, 4 J=1.14 Hz, 2H), 7.63 (dd, 3 J=3.80 Hz, 4 J=1.15 Hz, 2H), 7.18 (dd, 3 J=4.90 Hz, 4 J=3.96 Hz, 2H), 1.59 (s, 18H) NMR ( 1 H, CDCl 3 , 100 MHz), δ (ppm): 159.0, 148.7, 137.9, 133.8, 131.7, 129.6, 128.0, 110.2, 85.8, 27.6 HRMS (ASAP-) m/z: [M]- calculated for C 24 H 24 N 2 O 6 S 2 : 500.1076; found: 500.1079. Δ=0.6ppm. 1.3. Preparation of DPP-2’ Under argon atmosphere, DPP-2’’ (0.2 g, 0.40 mmol) was dissolved in dry DCM (40mL) and stirred 30 minutes at room temperature. A solution of N- Bromosuccinimide (0.17 g, 1.40 mmol, 3.5eq) in 10mL of DCM was added dropwise and the reaction mixture was stirred 16h at room temperature. The solution was quenched with water, extracted three times with ethyl acetate and the organic layer was dried over magnesium sulfate. Solvents were removed under reduce pressure at 25°C to afford the desired compound as a dark solid (0.26 g, 100%). MW (g.mol -1 ): 658.38 NMR ( 1 H, CDCl3, 400 MHz), δ (ppm): 8.08 (d, 3 J=4.22 Hz, 2H), 7.16 (d, 3 J=4.26 Hz, 2H), 7), 1.53 (s, 18H) NMR ( 1 H, CDCl3, 400 MHz), δ (ppm): 158.6, 148.8, 136.7, 134.4, 131.0, 130.9, 120.8, 110.3, 86.3, 27.7 HRMS (ASAP-) m/z: [M]- calculated for C 24 H 22 N 2 O 6 S 2 : 655.9286; found: 655.9280. Δ=-0.9ppm. 1.4. Preparation of DPP-2 In a sealable tube, DPP-2’ (0.3 g, 0.41 mmol), boronic ester 1 (0.384 g, 1.22 mmol, 3 eq), and K 2 CO 3 (0.28 g, 2.03 mmol, 5eq) were placed under argon atmosphere and dissolved in THF (20mL) and water (6mL). The solution was degassed 30 minutes under argon in an ultrasonic bath and Pd(PPh 3 ) 4 (0.094 g, 0.081 mmol, 0.2 eq) was added. The reaction mixture was heated overnight at 85°C. The reaction was cooled to room temperature, quenched with water, extracted 3 times with ethyl acetate, dried over magnesium sulfate and solvents are removed under reduce pressure. The crude was then heated 30 minutes at 180°C in the oven. After cooling to room temperature, the resulting solid was dissolved in THF and filtrated through celite. After solvents removal, the product was taken up in cyclohexane and filtrated through membrane to afford the desired compound as a red solid (0.19 g, 71%). MW (g.mol -1 ): 676.98 NMR ( 1 H, THF, 400 MHz) δ (ppm): 10.16 (s, 2H), 8.58 (d, 3 J=4.04 Hz, 2H), 7.62 (d, 4 J=1,74 Hz, 4H), 7.69 (d, 3 J=4.03 Hz, 2H), 7.72 (t, 4 J=1.72 Hz, 2H), 1.52 (s, 36H). NMR ( 13 C, CDCl3, 100 MHz) δ (ppm): 159.5, 149.6, 148.3, 133.9, 133.0, 132.7, 131.1, 131.0, 130.0, 129.9, 129.4, 128.1, 126.5, 126.3, 126.2, 125.8, 122.7, 120.9, 118.4, 107.9, 32.7, 28.8. HRMS (ASAP+) m/z: [M+H] + calculated for C42H49N2O2S2: 677.3235; found: 677.3254. Δ=2.8ppm. 2. Preparation of intermediate compound PPcy-th DPP-2 (0.150 g, 0.222 mmol) and p1 (0.10 g, 0.055 mmol, 2.5 eq) were heated to reflux in absolute toluene under argon. Phosphoryl chloride (0.17 mL, 1.78 mmol, 8 eq) was then added. The reaction was monitored by thin-layer chromatography. As soon as DPP-2 was used up or the concentration of by- products increased, the reaction was quenched with water and extracted 3 times with ethyl acetate. The organic layer was dried over magnesium sulfate and solvents were evaporated. The crude product was treated with methanol in an ultrasonic bath. The solid was collected by filtration and washed with methanol until the filtrate was colorless to afford the desired compound as a dark green solid (0.093 g, 43%). MW (g.mol -1 ): 993.30. NMR ( 1 H, CDCl3, 300 MHz) δ (ppm): 13.76 (s, 2H), 8.71 (d, 3 J=5.22 Hz, 2H), 7.83 (s, 2H), 7.75 (d, 4 J=1.64 Hz, 8H), 7.50 (d, 4 J=1.91 Hz, 4H), 7.48 (d, 4 J=1.44 Hz, 2H), 7.46 (t, 4 J=1.88 Hz, 2H), 3.93 (s, 6H), 1.38 (s, 36H). NMR ( 13 C, CDCl3, 300 MHz) δ (ppm): 149.6, 148.3, 133.9, 133, 132.8, 131.1, 131, 130, 129.9, 129.5, 128.1, 126.6, 126.4, 126.2, 125.9, 122.8, 121.0, 118.5, 107.9, 32.8, 28.9. HRMS (ES+) m/z: [M+Na]+ calculated for C 60 H 60 N 6 O 4 S 2 Na: 1015.4015; found: 1015.3998. Δ=-1.7ppm. 4. Preparation of intermediate compound PPcy-th-3 Under argon atmosphere, PPcy-th (0.035 g, 0.035 mmol,) and N,N- diisopropylethylamine (0.100 mL, 0.353 mmol, 10 eq) were heated to reflux in dry dichloromethane. Bis(4-(tert-butyl)phenyl)chloroborane (0.1 mL) was added dropwise and the mixture was heated to reflux for 10min. The reaction mixture was quenched with water, extracted three times with dichloromethane and dried over MgSO4. After removing the solvent, the crude product was purified by column chromatography using DCM/EP (7:3) as eluent to afford the desired compound as a purple solid (0.006 g, 11%). MW (g.mol -1 ): 1544.82 NMR ( 1 H, CDCl3, 300 MHz) δ (ppm): 8.12 (d, 3 J=6.59 Hz, 2H), 7.96 (d, 4 J=1.23 Hz, 2H), 7.30 (t, 4 J=1.71 Hz, 2H), 7.26 (m, 4H), 7.17 (q, 3 J=3.64 Hz, 16H), 6.80 (d, 3 J=3.78 Hz, 2H), 6.76 (d, 3 J=8.84 Hz, 2H), 6.25 (d, 3 J=3.77 Hz, 2H), 3.80 (s, 6H), 1.31 (s, 36H), 1.29 (s, 36H). HRMS (ASAP-) m/z: [M]- calculated for C 100 H 110 N 6 O 4 S 2 10 B 2 : 1542.8289; found: 1542.8281. Δ=-0.5ppm. 5. Preparation of S3 PPcy-th-3 (0.006, 0.004 mmol) was stirred at room temperature in THF (5mL). A solution of LiOH (0.002 g, 0.078 mmol, 20 eq) in water (1mL) is added dropwise in the reaction mixture and stirred for 1h. Aqueous hydrochloric acid preparation (2M) was added slowly until pH=4. The remaining solution is extracted 3 times with ethyl acetate. After evaporation, the crude product was dissolved in DCM and EP was added. The resulting precipitate was collected by filtration and washed with EP to afford the desired compound as a purple solid (0.004 g, 69%). MW (g.mol -1 ): 1517.70 NMR ( 1 H, CDCl3, 300 MHz) δ (ppm): 8.11 (d, 3 J=6.50 Hz, 2H), 7.98 (s, 2H), 7.28 (t, 4 J=1.70 Hz, 2H), 7.24 (d, 4 J=1.76 Hz, 4H), 7.17 (q, 3 J=6.68 Hz, 18H), 6.79 (d, 3 J=3.77 Hz, 2H), 6.25 (d, 3 J=3.75 Hz, 2H), 1.31 (s, 36H), 1.21 (s, 36H) HRMS (ASAP-) m/z: [M]- calculated for C 98 H 106 N 6 O 4 S 2 10 B 2 : 1514.7976; found: 1514.8020. Δ=2.9ppm. Example 4: Preparation of sensitizer S4 1. Preparation of intermediate compound As-PPcy-1 1.1. Preparation of As-DPP-1 DPP-1 (0.200 g, 0.301 mmol) were refluxed in 1mL POCl 3 for 3h. The POCl 3 was distilled off and the residue was dried on vacuum. p1 (0.110 mg, 0.602 mmol, 2 eq) dissolved in 10ml of abs. THF were added and the mixture was heated to reflux for 1 h. After cooling to room temperature, water was added and extracted 3 times with dichloromethane. The organic layer was dried over magnesium sulfate and solvents were evaporated. The crude product was treated with methanol in an ultrasonic bath and then filtrated on membrane and washed with methanol until the filtrate was colorless. The resulting blue product (0.139 mg, 56%) was pure enough for further reactions. MW (g.mol -1 ) : 823.09 NMR ( 1 H, CDCl3, 300 MHz) δ (ppm) : 13.87 (s, 1H), 8.77 (d, 3 J=5.08 Hz, 1H), 8.45 (d, 3 J=8.45 Hz, 2H), 8.23 (s, 1H), 7.85 (q, 3 J=5.56 Hz, 4H), 7.74 (s, 1H), 7.65 (dd, 3 J=6.81 Hz, 4 J=1.54 Hz, 4H), 7.51 (dd, 3 J=3.15 Hz, 4 J=1.71 Hz, 4H), 7.46 (d, 3 J=3.53 Hz, 2H), 3.95 (s, 3H), 1.41 (s, 16H), 1.39 (s, 16H) HRMS (ES+) m/z: [M-H]+ calculated for C 55 H 59 N 4 O 3 S: 823.4587; found: 823.4589. Δ =0.2ppm. 1.2. Preparation of As-PPcy-H-1 As-DPP-1 (0.080 g, 0.097 mmol) and 2-(5-Bromopyridin-2-yl)acetonitrile (0.023 g, 0.117 mmol, 1.2 eq) were heated to reflux in absolute toluene under argon. Phosphoryl chloride (0.05 mL, 0.486 mmol, 5 eq) was then added. The reaction was monitored by thin-layer chromatography. As soon as As-DPP-1 was fully consumed or the concentration of by-products increased, the reaction was quenched with water and extracted 3 times with ethyl acetate. The organic layer was dried over magnesium sulfate and solvents were evaporated. The crude product was treated with methanol in an ultrasonic bath. The solid was collected by filtration and washed with methanol until the filtrate was colorless to afford the desired compound as a green solid (0.076 g, 78%). MW (g.mol -1 ): 1002.11 NMR ( 1 H, CDCl3, 400 MHz) δ (ppm): 13.50 (s, 1H), 13.20 (s, 1H), 8.60 (dd, 3 J=5.17 Hz, 4 J=0.74 Hz, 1H), 8.54 (dd, 4 J=2.40 Hz, 4 J=0.64 Hz, 1H), 7.94 (s, 1H), 7.76 (qd, 3 J=8.75 Hz, 4 J=1.90 Hz, 8H), 7.62 (dd, 3 J=8.64 Hz, 4 J=2.37 Hz, 1H), 7.51 (dd, 4 J=2.44 Hz, 4 J=1.68 Hz, 5H), 7.47 (t, 4 J=1.72 Hz, 2H), 7.27 (d, 3 J=8.48 Hz, 1H), 3.95 (s, 3H), 1.39 (s, 18H), 1.38 (s, 18H) NMR ( 13 C, CDCl3, 100 MHz) δ (ppm): 165.2, 156.4, 153.8, 151.2, 148.4, 148.2, 144.9, 144.8, 139.5, 139.2, 138.0, 130.2, 127.9, 126.7, 122.13, 121.7, 120.4, 117.7, 115.0, 52.7, 35.0, 31.5 HRMS (ES-) m/z: [M]- calculated for C 62 H 60 N 6 O 2 79 Br: 999.3961; found: 999.3951. Δ= 1.0 ppm. 1.3. Preparation of As-PPcy-1 Under argon atmosphere, As-PPcy-H-1 (0.066 g, 0.082 mmol,) and N,N- diisopropylethylamine (0.110 mL, 0.659 mmol, 10 eq) were heated to reflux in dry dichloromethane. Chloro(diphenyl)borane (0.1 mL) was added dropwise and the mixture was heated to reflux for 10min. The reaction mixture was then quenched with water, extracted three times with dichloromethane and dried over MgSO 4 . After removing the solvent, the crude product was purified by column chromatography using petrol ether/CH 2 Cl 2 (3/7) as eluent to afford the desired compound as a dark green solid (0.044 g, 50%). MW (g.mol -1 ): 1330.14. NMR ( 1 H, CDCl3, 400 MHz) δ (ppm): 7.92 (d, 3 J=6.05 Hz, 1H), 7.89 (d, 4 J=1.77 Hz, 2H), 7.55 (dd, 3 J=6.92 Hz, 4 J=2.16 Hz, 1H), 7.42 (d, 4 J=0.86 Hz, 2H), 7.36 (dd, 3 J=10.29 Hz, 4 J=1.52 Hz, 4H), 7.25 (d, 3 J=9.08 Hz, 1H), 7.17 (m, 20H), 7.08 (dd, 3 J=8.32 Hz, 3 J=9.84 Hz, 4H), 6.84 (dd, 3 J=8.36 Hz, 4 J=3.20 Hz, 4H), 3.81 (s, 3H), 1.41 (s, 18H), 1.40 (s, 18H). NMR ( 13 C, CDCl3, 100 MHz) δ (ppm): 163.5, 156.4, 155.9, 150.9, 150.8, 148.7, 145.7, 145.5, 144.9, 144.7, 142.7, 142.5, 142.1, 140.3, 140.1, 139.7, 133.8, 133.7, 130.4, 129.7, 129.7, 127.6, 127.5, 126.6, 126.4, 125.6, 125.6, 122.3, 122.2, 122.1, 121.8, 121.5, 121.4, 116.8, 116.3, 112.7, 34.9, 31.5. HRMS (ASAP-) m/z: [M]- calculated for C86H7910B2N6O2 79 Br: 1326.5707; found: 1326.5734. Δ=2.0ppm. 2. Preparation of intermediate compound HD-1 2.1. Preparation of HD-1’’ In a sealable tube, 4-Bromotriphenylamine (1 g, 3.08 mmol), KIO 3 (0.442 g, 2.06 mmol, 0.7 eq), and KI (0.696 g, 4.19 mmol, 1.36 eq) were placed under argon atmosphere, dissolved in AcOH (16mL) and heated at 85°C overnight. The reaction mixture was quenched using saturated solution of Na 2 S 2 O 3 and stirred for 1h at room temperature. The solution was extracted 3 times with dichloromethane, dried over magnesium sulfate and solvents are removed under reduce pressure. The crude was purified by column chromatography using petrol ether/CH 2 Cl 2 (9/1) as eluent to afford the final pure product as white crystals (1.4 g, 80%). MW (g.mol -1 ): 576.01. NMR ( 1 H, CDCl3, 400 MHz) δ (ppm): 7.53 (d, 3 J=8.86 Hz, 4H), 7.35 (d, 3 J=8.90 Hz, 2H), 6.92 (d, 3 J=8.88 Hz, 2H), 6.80 (d, 3 J=8.85 Hz, 4H). 2.2. Preparation of HD-1’ In a sealable tube, HD-1’’ (1 g, 1.74 mmol), 2,4-Dibutoxyphenylboronic Acid (1.02 g, 3.82 mmol, 2.2 eq), and K2CO3 (1.19 g, 8.70 mmol, 5eq) were placed under argon atmosphere and dissolved in toluene (20mL) and water (6mL). The solution was degassed 30 minutes under argon in an ultrasonic bath and Pd(PPh 3 ) 4 (0.4 g, 0.348 mmol, 0.2 eq) was added. The reaction mixture was heated overnight at 65°C. The reaction was cooled to room temperature, quenched with water, extracted 3 times with ethyl acetate, dried over magnesium sulfate and solvents are removed under reduce pressure. The crude was purified by column chromatography using petrol ether/CH 2 Cl 2 (9/1) as eluent to afford the final pure product as white solid (0.580 g, 44%). MW (g.mol -1 ): 764.85. NMR ( 1 H, CDCl3, 400 MHz) δ (ppm): 7.44 (d, 3 J=8.67 Hz, 4H), 7.33 (d, 3 J=8.88 Hz, 2H), 7.23 (d, 3 J=8.82 Hz, 2H), 7.12 (d, 3 J=8.64 Hz, 4H), 7.04 (d, 3 J=8.85 Hz, 2H), 6.54 (m, 4H), 3.97 (m, 8H), 1.75 (m, 8H), 1.41 (m, 8H), 0.94 (m, 12H). 2.3. Preparation of HD-1 In a sealable tube, HD-1’ (0.580 g, 0.760 mmol, bis(pinacolato)diboron (0.212 g, 0.836 mmol, 1.1 eq), potassium acetate (0.223 g, 2.28 mmol, 3 eq) and Pd(dppf)Cl 2 (0,028 g, 0.038 mmol, 0.05 eq) were placed under argon atmosphere and dissolved in dry DMF (10mL). The reaction mixture was heated overnight at 80°C. The reaction was cooled to room temperature, quenched with water, extracted three times with ethyl acetate, dried over magnesium sulfate and solvents were removed under reduce pressure. The crude was purified by column chromatography using petrol ether/CH 2 Cl 2 (1/1) as eluent to afford the final product as white solid (0.554 g, 90%). MW (g.mol-1): 811.91. NMR ( 1 H, CDCl3, 300 MHz) δ (ppm): 7.67 (d, 3 J=8.59 Hz, 2H), 7.42 (d, 3 J=8.72 Hz, 4H), 7.26 (d, 3 J=8.56 Hz, 2H), 7.14 (d, 3 J=8.69 Hz, 4H), 7.12 (d, 3 J=8.58 Hz, 2H), 6.54 (m, 4H), 3.97 (m, 8H), 1.75 (m, 8H), 1.41 (m, 8H), 1.36 (s, 12H), 0.94 (m, 12H). 3. Preparation of intermediate compound As-PPcy-HD-1 In a sealable tube, As-PPcy-1 (0.015 g, 0.013 mmol), HD-1 (0.018 g, 0.026 mmol, 2 eq), and K2CO3 (0.007 g, 0.056 mmol, 5eq) were placed under argon atmosphere and dissolved in toluene (3mL) and water (1mL). The solution was degassed 30 minutes under argon in an ultrasonic bath and Pd(PPh 3 ) 4 (0.002 g, 0.001 mmol, 0.1 eq) was added. The reaction mixture was heated overnight at 85°C. The reaction was cooled to room temperature, quenched with water, extracted 3 times with dichloromethane, dried over magnesium sulfate and solvents are removed under reduce pressure. The crude was first purified by column chromatography using petrol ether/CH 2 Cl 2 (9/1) as eluent and then by recycling HPLC to afford the final pure product as a brown-green solid (0.009 g, 41%). MW (g.mol -1 ): 1935.18. NMR ( 1 H, CDCl3, 300 MHz) δ (ppm): 7.41 (m, 7H), 7.35 (m, 5H), 7.23 (d, 3 J=9.00 Hz), 7.16 (s, 20H), 7.08 (m, 9H), 6.85 (d, 3 J=7.22 Hz, 4H), 6.53 (m, 4H), 3.96 (m, 8H), 3.79 (s, 3H), 1.73 (m, 8H), 1.52 (m, 8H), 1.41 (s, 18H), 1.39 (s, 18H), 0.94 (m, 12H). NMR ( 13 C, CDCl3, 75 MHz) δ (ppm): 159.6, 150.8, 133.8, 127.5, 126.3, 125.6, 121.5, 105.3, 100.4, 68.1, 67.7, 34.9, 31.5, 31.3, 31.1, 19.2, 13.8, 13.8. HRMS (ES+) m/z: [M+Na]+ calculated for C 132 H 133 10 B 2 N 7 O 6 Na: 1955.0474; found: 1955.0444. Δ=-1.5ppm. 4. Preparation of S4 As-PPcy-HD-1 (0.008, 0.004 mmol) was stirred at room temperature in THF (5mL). A solution of LiOH (0.002 g, 0.083 mmol, 20 eq) in water (1mL) was added dropwise in the reaction mixture and stirred for 1h. Aqueous hydrochloric acid preparation (2M) is added slowly until pH=4. The remaining solution is extracted 3 times with ethyl acetate. After evaporation, the crude product was dissolved in DCM and EP was added. The resulting precipitate was collected by filtration and washed with EP to afford the desired compound as a brown-green solid (0.006 g, 76%). MW (g.mol -1 ): 1921.15. NMR ( 1 H, CDCl3, 400 MHz) δ (ppm): 7.41 (m, 7H), 7.35 (m, 5H), 7.23 (d,), 7.16 (s, 20H), 7.08 (m, 9H), 6.85 (d, 4H), 6.53 (m, 4H), 3.96 (m, 8H), 3.79 (s, 3H), 1.73 (m, 8H), 1.52 (m, 8H), 1.41 (s, 18H), 1.39 (s, 18H), 0.94 (m, 12H). HRMS (ES-) m/z: [M-H]- calculated for C 131 H 130 N 7 O 6 10 B 2 : 1917.0341; found: 1917.0.300. Δ=-2.1ppm. Example 5: Preparation of sensitizer S5 1. Synthesis of intermediate p2 1.1. Preparation of compound p2’’ Methyl 4-bromopicolinate (1 g, 4.63 mmol) was dissolved in 15mL EtOH, the solution was cooled to 0-10°C in an ice bath, and then NaBH 4 (0.35 g, 9.26mmol, 2 eq)) was added dropwise to the above mixture. The temperature of the reaction mixture was increased to 60°C and left for 3 h. The mixture was poured into 20mL ice water and stirred for 30 min. The resulting solution was extracted with ethyl acetate. The combined organic phases were washed with saturated brine, dried over anhydrous MgSO 4 , and filtered. The solution was concentrated under reduced pressure to afford a yellow oil (0.810 g, 93%). MW (g.mol -1 ): 188.02. NMR ( 1 H, CDCl3, 300 MHz) δ (ppm): 8.37 (d, 3 J=5.33 Hz, 1H), 7.49 (s, 4J=0.53 Hz, 1H), 7.38 (dd, 3 J=5.32 Hz, 4 J=1.79 Hz, 1H), 4.74 (s, 2H). 1.2. Preparation of compound p2’ PBr3 (10.0 mL, 105.28 mmol) in 20 mL CHCl3 was added dropwise to the solution of p2’’ (3.60 g, 16.51 mmol) in 100 mL CHCl 3 . The reaction mixture was heated under reflux for 6 h. The resulting solution was mixed with 150 mL ice water and the pH was adjusted to 10 with potassium carbonate. The resulting solution was extracted with dichloromethane. The combined organic phases were washed with brine, dried over Na 2 SO 4 , filtered, and concentrated under reduced pressure to afford a white solid (5.28 g, 78%). MW (g.mol -1 ): 250.92. NMR ( 1 H, CDCl3, 300 MHz) δ (ppm): 8.38 (d, 3 J=5.33 Hz, 1H), 7.62 (d, 4 J=1.49 Hz, 1H), 7.38 (dd, 3 J=5.32 Hz, 4 J=1.79 Hz, 1H), 4.49 (s, 2H). 1.3. Preparation of compound p2 Under argon atmosphere, p2’ (2.5 g, 13.5 mmol) is dissolved in dry acetonitrile (250mL) and stirred at room temperature. TMSCN (2.53 mL, 20.2 mmol, 1.5 eq) and TBAF (20.2 mL, 20.2 mmol, 1.5 eq) were added and the reaction mixture heated 30 minutes at reflux. Solvents were evaporated. The resulting solid was solubilized in AcOEt and washed 4 times with brine The organic layer was dried over magnesium sulfate and solvents were evaporated. A brown oil (2.29 g, 96%) was obtained without further purification. MW (g.mol -1 ): 197.04. NMR ( 1 H, CDCl3, 400 MHz) δ (ppm): 8.41 (d, 3 J=5.33 Hz, 1H), 7.63 (d, 4 J=1.75 Hz, 1H), 7.38 (dd, 3 J=5.31 Hz, 4 J=1.81 Hz, 1H), 4.49 (s, 2H). NMR ( 13 C, CDCl3, 100 MHz) δ (ppm): 151.8, 150.6, 134.0, 126.5, 125.7, 116.2, 26.2893. HRMS (ASAP+) m/z: [M+H]+ calculated for C 7 H 6 N 2 Br: 196.9714; found: 196.9721. Δ=3.6ppm. 2. Preparation of intermediate As-PPcy-2 2.1. Preparation of As-PPcy-H-2 As-DPP-1 (0.065 g, 0.078 mmol) and p2 (0.018 g, 0.095 mmol, 1.2 eq) were heated to reflux in absolute toluene under argon. Phosphoryl chloride (0.04 mL, 0.395 mmol, 5 eq) was then added. The reaction was monitored by thin-layer chromatography. As soon as As-DPP-1 was fully consumed or the concentration of by-products increased, the reaction was quenched with water and extracted 3 times with ethyl acetate. The organic layer was dried over magnesium sulfate and solvents were evaporated. The crude product was treated with methanol in an ultrasonic bath. The solid was collected by filtration and washed with methanol until the filtrate was colorless to afford the desired compound as a blue-green solid (0.034 g, 43%). MW (g.mol-1): 1002.11. NMR ( 1 H, CDCl3, 400 MHz) δ (ppm): 13.51 (m, 2H), 8.62 (d, 3 J=5.28 Hz, 1H), 8.28 (d, 3 J=5.35 Hz, 1H), 7.90 (s, 1H), 7.76 (q, 3 J=7.88 Hz, 8H), 7.54 (dd, 3 J=9.32 Hz, 4 J=1.23 Hz, 2H), 7.50 (t, 4 J=1.91 Hz, 4H), 7.47 (m, 2H), 7.13 (d, 3 J=7.44 Hz, 4 J=1.68 Hz, 1H), 3.94 (s, 3H), 1.38 (s, 18H), 1.37 (s, 18H). NMR ( 13 C, CDCl3, 100 MHz) δ (ppm): 151.2, 130.3, 126.7, 122.1, 121.6, 35.0, 31.5425. HRMS (ES-) m/z: [M]- calculated for C 62 H 60 N 6 O 2 79 Br: 999.3961; found: 999.3961. Δ=0.0ppm. 2.2. Preparation of As-PPcy-2 Under argon atmosphere, As-PPcy-H-2 (0.035 g, 0.035 mmol,) and N,N- diisopropylethylamine (0.060 mL, 0.350 mmol, 10 eq) were heated to reflux in dry dichloromethane. Chloro(diphenyl)borane (0.1 mL) was added dropwise and the mixture was heated to reflux for 10min. The reaction mixture was then quenched with water, extracted three times with dichloromethane and dried over MgSO 4 . After removing the solvent, the crude product was purified by column chromatography using petrol ether/CH 2 Cl 2 (3/7) as eluent to afford the desired compound as a dark green solid (0.022 g, 47%). MW (g.mol-1): 1330.14. NMR ( 1 H, CDCl3, 400 MHz) δ (ppm): 7.92 (d, 3 J=6.05 Hz, 1H), 7.89 (d, 4 J=1.77 Hz, 2H), 7.64 (d, 3 J=6.40 Hz, 1H), 7.53 (d, 4 J=1.6 Hz, 1H), 7.42 (d, 4 J=0.76 Hz, 2H), 7.36 (m, 4H), 7.20 (dd, 3 J=5.96 Hz, 4 J=1.6 Hz, 2H), 7.16 (m, 20H), 7.08 (dd, 3 J=7.96 Hz, 4 J=2.64 Hz, 4H), 6.84 (dd, 3 J=8.48 Hz, 4 J=1.72 Hz, 4H), 3.81 (s, 3H), 1.41 (s, 18H), 1.40 (s, 18H). NMR ( 13 C, CDCl3, 100 MHz) δ (ppm): 163.5, 156.3, 150.8, 150.7, 150.5, 145.8, 144.9, 144.6, 142.7, 142.6, 140.2, 140.1, 139.7, 136.7, 133.7, 133.7, 130.4, 130.4, 129.7, 129.7, 129.6, 127.6, 126.4, 125.6, 125.5, 123.7, 122.2, 122.1, 121.8, 121.7, 121.4, 116.9, 116.3, 115.2, 34.9. HRMS (ES+) m/z: [M+Na] + calculated for C 86 H 79 10 B 2 N 6 O 2 Na 79 Br: 1349.5604; found: 1349.5614. Δ=0.7ppm. 3. Preparation of intermediate As-PPcy-HD-2 In a sealable tube, As-PPcy-2 (0.022 g, 0.016 mmol), HD-1 (0.027 g, 0.033 mmol, 2 eq), and K 2 CO 3 (0.011 g, 0.085 mmol, 5eq) were placed under argon atmosphere and dissolved in toluene (3mL) and water (1mL). The solution was degassed 30 minutes under argon in an ultrasonic bath and Pd(PPh 3 ) 4 (0.004 g, 0.002 mmol, 0.1 eq) was added. The reaction mixture was heated overnight at 85°C. The reaction was cooled to room temperature, quenched with water, extracted 3 times with dichloromethane, dried over magnesium sulfate and solvents are removed under reduce pressure. The crude was first purified by column chromatography using petrol ether/CH 2 Cl 2 (9/1) as eluent and then by recycling HPLC to afford the final pure product as a dark-green solid (0.030 g, 94%). MW (g.mol -1 ): 1935.18. NMR ( 1 H, CDCl3, 400 MHz) δ (ppm): 7.84 (m, 3H), 7.56 (d, 4 J=1.69 Hz, 1H), 7.43 (d, 3 J=8.48 Hz, 4H), 7.41 (t, 4 J=2.08 Hz, 2H), 7.39 (m, 2H), 7.36 (dd, 3 J=8.48 Hz, 4 J=1.72 Hz, 4H), 7.23 (d, 3 J=11.2 Hz, 2H), 7.17 (m, 20H), 7.11 (d, 3 J=8.88 Hz, 6H), 7.08 (m, 3H), 7.06 (d, 4 J=0.96 Hz, 2H), 6.98 (dd, 3 J=6.64 Hz, 4 J=2.24 Hz, 1H), 6.85 (dd, 3 J=8.32 Hz, J=5.80 Hz, 4H), 6.53 (m, 4H), 3.96 (m, 8H), 3.79 (s, 3H), 1.73 (m, 8H), 1.52 (m, 8H), 1.41 (s, 18H), 1.39 (s, 18H), 0.94 (m, 12H). NMR ( 13 C, CDCl3, 100 MHz) δ (ppm): 159.7, 156.9, 150.8, 150.7, 144.6, 134.4, 133.8, 130.8, 130.4, 127.8, 127.4, 126.9, 126.2, 125.5, 125.4, 124.7, 122.8, 121.5, 105.4, 100.5, 68.1, 67.8, 34.9, 31.5, 31.3, 31.1, 26.9, 19.2. HRMS (ES+) m/z: [M] + calculated for C 132 H 133 10 B 2 N 7 O 6 : 1935.0576; found: 1932.0484. Δ=4.8 ppm. 4. Preparation of S5 As-PPcy-HD-2 (0.030, 0.015 mmol) was stirred at room temperature in THF (5mL). A solution of LiOH (0.007 g, 0.310 mmol, 20 eq) in water (1mL) is added dropwise in the reaction mixture and stirred for 1h. Aqueous hydrochloric acid preparation (2M) was added slowly until pH=4. The remaining solution was extracted 3 times with ethyl acetate. After evaporation, the crude product was dissolved in DCM and EP was added. The resulting precipitate was collected by filtration and washed with EP to afford the desired compound as a dark green solid (0.027 g, 90%). MW (g.mol -1 ): 1921.15. NMR ( 1 H, CDCl3, 400 MHz) δ (ppm): 7.84 (m, 3H), 7.43 (d, 3 J=8.48 Hz, 4H), 7.41 (t, 4 J=2.08 Hz, 2H), 7.39 (m, 2H), 7.36 (dd, 3 J=8.48 Hz, 4 J=1.72 Hz, 4H), 7.23 (d, 3 J=11.2 Hz, 2H), 7.17 (m, 20H), 7.11 (d, 3 J=8.88 Hz, 6H), 7.08 (m, 3H), 7.06 (d, 4 J=0.96 Hz, 2H), 6.85 (dd, 3 J=8.32 Hz, J=5.80 Hz, 4H), 6.53 (m, 4H), 3.96 (m, 8H), 1.73 (m, 8H), 1.52 (m, 8H), 1.41 (s, 18H), 1.39 (s, 18H), 0.94 (m, 12H). HRMS (ES-) m/z: [M]- calculated for C 131 H 130 N 7 O 6 S 2 10 B 2 : 1917.0341; found: 1917.0352. Δ=0.6ppm. Example 6: Preparation of sensitizer S6 1. Preparation of intermediate BC-1’’ Under a nitrogen atmosphere, 4-bromophenol (2.00 g, 11.56 mmol), KI (0.48 g, 2.89 mmol), 18-crown-6 (0.76 g, 2.89 mmol, 0.25 eq) and K 2 CO 3 (4.00 g, 28.90 mmol, 2.5 eq) were added into 20 mL of dry DMF in a two-neck flask. After stirring for 5 min, 2- ethylhexyl bromide (5.58 g, 28.90 mmol, 2.5 eq) was added via a syringe. The mixture was heated to reflux for 24h. The cooled mixture was poured into water and then extracted with diethyl ether there times. The combined organic phase was dried over MgSO 4 . After removing the organic solvents, the residue was purified through a column chromatography on silica gel using a mixture of petrol ether and dichloromethane (9 :1) as eluent to give compound BC-1’’ (3.02 g, 92%) as a colorless oil. MW (g.mol -1 ): 285.23 NMR ( 1 H, CDCl 3 , 400 MHz) δ (ppm): 7.53 (d, 3 J=8.99, 2H), 6.67 (d, 3 J=9.00 Hz, 2H), 3.80 (d, 3 J=5.68 Hz, 2H), 1.70 (m, 1H), 1.43 (m, 4H), 1.29 (m, 4H), 0.89 (m, 4H) 2. Preparation of BC-1’ Under an argon atmsophere, BC-1’’ (2.00 g, 7.02 mmol) was dissolved in dry THF (8 mL) and cooled to -78 °C in a dry ice/acetone bath. n-BuLi solution in hexane (3.90 mL, 9.82 mmol, 1.4 eq) was added dropwise to the mixture, left 2h at -78°c and warm up for additional 2h at room temperature. The reaction mixture was cooled again at -78)C and Me 2 SnCl 2 (0.77 g, 3.51 mmol, 0.5 eq) was added. The reaction was stirred at -78 °C for 20 min, and then the bath was removed and the reaction allowed to warm to room temperature and stir overnight. Solvents were removed under reduced pressure and after purification through column chromatography on silica gel (dichloromethane with 1% Et 3 N as eluent) and recycling HPLC, a colorless oil was obtained (3.30 g, 84%). MW (g.mol -1 ): 559.42 NMR ( 1 H, CDCl 3 , 400 MHz) δ (ppm): 7.41 (d, 3 J=8.50 Hz, 4H), 6.91 (d, 3 J=8.52 Hz, 4H), 3.84 (dd, 3 J=5.56 Hz, 4 J=1.2 Hz, 4H), 1.72 (m, 2H), 1.44 (m, 8H), 1.31 (m, 8H), 0.91 (m, 12H), 0.45 (s, 6H) NMR ( 13 C, CDCl 3 , 100 MHz) δ (ppm): 137.2, 114.7, 70.1, 39.3, 30.5, 29.0, 23.8, 23.0, 14.0, 11.1 3. Preparation of BC-1 Under an atmosphere, BC-1’ (0.15 g, 0.27 mmol) was dissolved in 1 mL of dry dichloroethane. A 1M solution of BCl 3 was added dropwise at room temperature and the mixture was heated at 80°C overnight. After cooling, the solution of BC-1 was used without further purification due to its high instability. MW (g.mol -1 ): 456.90 4. Preparation of intermediate PPcy-4 Under argon atmosphere, PPcy (0.060 g, 0.061 mmol,) and N,N- diisopropylethylamine (0.10 mL, 0.605 mmol, 10 eq) were heated to reflux in dry dichloromethane. BC-1 in dichloroethane (0.3 mL) was added dropwise and the mixture was heated to reflux for 10min. The reaction mixture was quenched with water, extracted three times with dichloromethane and dried over MgSO 4 . After removing the solvent, the crude product was purified by column chromatography using DCM/EP (7:3) as eluent to afford the desired compound as a green solid (0.016 g, 15%). MW (g.mol -1 ): 1821.14 NMR ( 1 H, CDCl 3 , 400 MHz) δ (ppm): 7.99 (d, 3 J=6.60Hz, 2H), 7.87 (d, 4 J=1.19 Hz, 2H), 7.38 (m, 6H), 7.17 (dd, 3 J=6.60 Hz, 4 J=1.74 Hz, 2H), 7.14 (d, 3 J=8.28 Hz, 4H), 7.02 (d, 3 J=8.23 Hz, 8H), 6.82 (d, 3 J=7.56 Hz, 4H), 6.68 (d, 3 J=8.45 Hz, 8H), 3.80 (s, 6H), 3.71 (m, 8H), 1.67 (m, 4H), 1.38 (s, 36H), 1.30 (m, 30H), 0.89 (m, 26H) HRMS (ES+) m/z: [M]+ calculated for C 118 H 141 10 B 2 N 6 O 8 : 1819.1461; found: 1819.1399. Δ=-3.4ppm. 5. Preparation of S6 As-PPcy-HD-3 (0.015 g, 0.008 mmol) was stirred at room temperature in THF (5mL). A solution of LiOH (0.004 g, 0.16 mmol, 20 eq) in water (1mL) was added dropwise in the reaction mixture and stirred for 1h. Aqueous hydrochloric acid preparation (2M) is added slowly until pH=4. The remaining solution is extracted 3 times with ethyl acetate. After evaporation, the crude product was dissolved in DCM and EP was added. The resulting precipitate was collected by filtration and washed with EP to afford the desired compound as a green solid (0.011 g, 74%). MW (g.mol -1 ): 1793.11 NMR ( 1 H, CDCl3, 400 MHz) δ (ppm): .99 (d, 3 J=6.60Hz, 2H), 7.87 (d, 4 J=1.19 Hz, 2H), 7.38 (m, 6H), 7.17 (dd, 3 J=6.60 Hz, 4 J=1.74 Hz, 2H), 7.14 (d, 3 J=8.28 Hz, 4H), 7.02 (d, 3 J=8.23 Hz, 8H), 6.82 (d, 3 J=7.56 Hz, 4H), 6.68 (d, 3 J=8.45 Hz, 8H), 3.71 (m, 8H), 1.67 (m, 4H), 1.38 (s, 36H), 1.30 (m, 30H), 0.89 (m, 26H) HRMS (ES-) m/z: [M-H]- calculated for C 118 H 141 10 B 2 N 6 O 8 : 1790.1070; found: 1790.1025. Δ=-2.5ppm. Example 7: Preparation of sensitizer S7 1. Preparation of intermediate HD-2 In a sealable tube, bis(4-bromophenyl)amine (1 g, 3.06 mmol), 2,4- Dibutoxyphenylboronic Acid (2.44 g, 9.17 mmol, 3 eq), and K 2 CO 3 (2.00 g, 15.30 mmol, 5eq) were placed under argon atmosphere and dissolved in toluene (20mL) and water (6mL). The solution was degazed 30 minutes under argon in an ultrasonic bath and Pd(PPh 3 ) 4 (0.71 g, 0.61 mmol, 0.2 eq) was added. The reaction mixture was heated overnight at 65°C. The reaction is cooled to room temperature, quenched with water, extracted 3 times with ethyl acetate, dried over magnesium sulfate and solvents are removed under reduce pressure. The crude was purified by column chromatography using EP/DCM (6:4) as eluent to afford the final pure product as white solid (1.20 g, %). MW (g.mol -1 ): 609.85 NMR ( 1 H, CDCl 3 , 400 MHz) δ (ppm): 7.74 (d, 3 J=8.70 Hz, 4H), 7.24 (d, 3 J=8.75 Hz, 2H), 7.11 (d, 3 J=8.71Hz, 4H), 6.54 (m, 4H), 4.00 (t, 3 J=6.56 Hz, 8H), 3.96 (t, 3 J=6.55 Hz, 4H) 1.76 (m, 8H), 1.49 (m, 8H), 0.99 (t, 3 J=7.35 Hz, 6H), 0.97 (t, 3 J=7.32 Hz, 6H) 2. Preparation of intermediate As-PPcy-HD-3 As-PPcy-2 (0.02 g, 0.015 mmol), HD-2 (0.011 g, 0.018 mmol), Na-tBuO (0.007 g, 0.075 mmol, 5eq), Pd(dba) 2 (5 mol-%) (dba = dibenzylideneacetone), tri-tert- butylphosphine tetrafluoroborate (5 mol-%) and 5 mL of dry and degazed toluene were placed in a flask under argon atmsophere. Then the reaction mixture was heated to 80 °C for 24 h. After the reaction mixture had been cooled to room temperature and the mixture was washed with CH 2 Cl 2 . After solvent removal, the crude was first purified by column chromatography using petrol ether/CH 2 Cl 2 (7/3) as eluent and then by recycling HPLC to afford the final pure product as a green solid (0.014 g, 50%). MW (g.mol -1 ): 1859.08 NMR ( 1 H, CDCl3, 300 MHz) δ (ppm): 7.77 (d, 4 J=1.32 Hz, 1H), 7.74 (d, 3 J=6.59 Hz, 1H), 7.44 (q, 3 J=8.46 Hz, 6H), 7.39 (m, 1H), 7.35 (m, 3H), 7.28 (d, 4 J=1.73 Hz, 2H), 7.14 (d, 3 J=8.62 Hz, 20H), 7.09 (m, 5H), 7.01 (dd, 3 J= 6.57 Hz, 4 J=1.71 Hz, 1H), 6.96 (d, 3 J=8.31 Hz, 2H), 6.92 ( 4 J=2.64 Hz, 1H), 6.80 (dd, 3 J=8.30 Hz, 4 J=3.87 Hz, 4H), 6.46 (m, 4H), 6.21 (dd, 3 J=5.85 Hz, 4 J=2.65 Hz, 1H), 3.94 (t, 3 J=6.46 Hz, 4H), 3.84 (t, 3 J=6.43 Hz, 4H), 3.77 (s, 3H), 1.54 (m, 8H), 1.39 (s, 18H), 1.34 (s, 18H), 0.98 (t, 3 J=7.31 Hz, 6H), 0.82 (t, 3 J=7.30 Hz, 6H) NMR ( 13 C, CDCl3, 75 MHz) δ (ppm): 163.9, 159.9, 158.4, 156.8, 154.9, 151.3, 150.7, 150.6, 148.1, 145.7, 144.8, 141.9, 140.9, 140.3, 138.7, 137.4, 133.7, 131.0, 130.8, 130.2, 127.3, 126.0, 125.4, 125.1, 122.0, 121.5, 121.5, 121.1, 116.5, 105.3, 100.3, 68.0, 67.9, 67.7, 52.8, 45.8, 34.9, 34.9, 31.5, 31.5, 31.3, 30.9, 29.7, 19.2, 13.8, 13.7, 9.0 HRMS (ES+) m/z: [M]+ calculated for C 126 H 129 10 B 2 N 7 O 6 : 1856.0263; found: 1856.0258. Δ=-0.3 ppm 3. Preparation of S5 As-PPcy-HD-3 (0.014, 0.007 mmol) was stirred at room temperature in THF (5mL). A solution of LiOH (0.004 g, 0.15 mmol, 20 eq) in water (1mL) was added dropwise in the reaction mixture and stirred for 1h. Aqueous hydrochloric acid preparation (2M) is added slowly until pH=4. The remaining solution is extracted 3 times with ethyl acetate. After evaporation, the crude product was dissolved in DCM and EP was added. The resulting precipitate was collected by filtration and washed with EP to afford the desired compound as a green solid (0.011 g, 79%). MW (g.mol -1 ): 1845.05 N MR (1H, CDCl 3 , 400 MHz) δ (ppm) : 7.77 (d, 4J=1.32 Hz, 1H), 7.74 (d, 3 J=6.59 Hz, 1H), 7.44 (q, 3 J=8.46 Hz, 6H), 7.39 (m, 1H), 7.35 (m, 3H), 7.28 (d, 4 J=1.73 Hz, 2H), 7.14 (d, 3 J=8.62 Hz, 20H), 7.09 (m, 5H), 7.01 (dd, 3 J= 6.57 Hz, 4 J=1.71 Hz, 1H), 6.96 (d, 3 J=8.31 Hz, 2H), 6.92 ( 4 J=2.64 Hz, 1H), 6.80 (dd, 3 J=8.30 Hz, 4 J=3.87 Hz, 4H), 6.46 (m, 4H), 6.21 (dd, 3 J=5.85 Hz, 4 J=2.65 Hz, 1H), 3.94 (t, 3 J=6.46 Hz, 4H), 3.84 (t, 3 J=6.43 Hz, 4H), 1.54 (m, 8H), 1.39 (s, 18H), 1.34 (s, 18H), 0.98 (t, 3 J=7.31 Hz, 6H), 0.82 (t, 3 J=7.30 Hz, 6H) HRMS (ES+) m/z: [M]+ calculated for C125H127 10 B2N7O6: 1842.0107; found: 1842.0052. Δ=-3.0 ppm Example 8: RESULTS - PROPERTIES OF S1-S7 When integrated into devices, this new family of dyes (S1-S7) is able to regenerate at faster half-time speed, ie. nanosecond time-scale, compared to state- of the art sensitizers which are in the range of microsecond time-scale. It has a very slow geminate recombination dynamic which affords in devices to reach quantitative injection yield with a broad range of electrolyte compositions. The results are shown in Figures 1 to 4. Steady-state absorption spectra were collected with a Analytik Jena UV-visible spectrophotometer using 1-cm-path-length cells. Emission spectra were collected with a FluoroLog emission spectrometer. The optical densities of the samples for emission spectroscopy were below 0.1 and the samples were excited at the wavelength of the maximum absorption band. 1H and 13 C NMR spectra were recorded on an AVANCE 300 UltraShield BRUKER. Chemical shifts are referenced relative to residual protium or carbon signal in the deuterated solvent. NMR spectra were recorded at room temperature, chemical shifts are written in ppm and coupling constants in Hz. Mass spectrometry was performed with a JEOL JMS-700 B/E spectrometer. The spectra of the dyes are dominated by a strong and thin absorption band peaking between 750 and 800 nm depending on the structure of the pyrrolopyrrole cyanines. This feature is particularly valuable for the application in colorless DSSCs because the absorbance is strongly localized on the NIR with low contribution in the visible region to maximize AVT. A comparison of the electronic spectra of dyes S1 and S3 demonstrates the bathochomic shift upon replacing a phenylene by a thiophenylene. In the same vein, introducing a trisarylamine donating group red shifts the absorbance by (dye S1 versus dye S4). All these dyes are strongly fluorescent with emission lifetimes in the range of few nanosecond at room temperature. The latter property indicates that the dye excited state is significantly long-lived to efficiently inject an electron in the conduction band of TiO 2 . Example 9: Hydrogen production experiments with dye sensitized photocatalytic systems 1. Preparation of surface-platinized TiO 2 nanoparticles by photodeposition 40 mL methanol was added to 2 g of commercially available TiO 2 nanoparticles (Sigma-Aldrich 21 nm particle size) in a quartz round-bottom-flask. A solution of 80 mg of H 2 PtCl 6 .6H 2 O in 1 mL of deionized water is added, and reaction medium is degassed with N2 for 30 min under vigorous stirring, then irradiated 1h by UV light (100 W). The particles were collected by filtration, washed thoroughly with methanol and then dried in vacuum overnight. The platinum-loading is measured by Atomic Absorption Spectroscopy (AAS) with 50 mg and 100 mg surface-platinized TiO 2 nanoparticles 40 min in 5 mL aqua regia (HNO 3 /HCl: 1/3), centrifuged 30 min at 10000 rpm, and the supernatant diluted in 20 mL distilled water. 2. Nanoparticles dye-loading determination The absorbance of 10 mL solution of the dye S1 at 0.1 M in EtOH/CHCl3: 9/1 is measured before 100 mg of surface-platinized TiO 2 nanoparticles are added. Then the medium is ultrasonically treated in water 90 min and centrifuged 30 min at 10000 rpm, the supernatant is replaced by 10 mL EtOH/CHCl3: 9/1 and centrifuged again 10 min at 10000 rpm. The absorbance of the two supernatants is measured and compared with the absorbance before for a dye-loading approximation. The real dye-loading measure is obtained by desorption of 10 mg nanoparticles in a 3 mL phenylphosphonic acid solution in DMF (20 mg per mL) 1h at 80°C. The absorbance of the solution is measured. 3. Hydrogen production and measurement 5 mL of a solution of Sacrificial Electron Donor (SED: ascorbic acid 0.1 M) basified by NaOH (0.5 M) to reach pH = 4 is added with 10 mg of the functionalized nanoparticles in a 6 mL photoreactor. The solution is then degassed with N 2 and illuminated with different light sources (1W LED, artificial AM 1.5 [1000 W/m 2 ] sun, natural sun). The amount of hydrogen produced is measured every hour by sampling the headspace of the cell by and analyzing it by gas chromatography upon integration of the area of H 2 peak and using a calibration curve. The gas chromatography column is a BR Molecular sieve 5A, SN: 1029974/BR80280-107 with a FID detector eluted with nitrogen. The results of the photocatalytic production of H 2 in DSP sensitized with the dye S1 upon irradiation with simulated sunlight (AM1.51000W/m 2 ) or natural sun or with two 3 Watts LED emitting at 740 nm are gathered in Table 1 and the results are illustrated on Figure 5. Table 1. Quantity of H 2 produced and turnover number (TON) measured after 6 hours of irradiation. Dye loading of S1: 4.68 nmol/mg de TiO 2 . Clearly, it can be observed that the dye sensitized photocatalytic (DSP) systems based on the pyrrolopyrrole cyanine dye S1 effectively produces H 2 even with photons carrying energy as low as 1.6 eV (740 nm). These experiments demonstrate that the pyrrolopyrrole cyanine dyes according to the invention are compatible with H 2 production in DSP with NIR energy of sunlight.