CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] The present PCT application claims the priority of U.S. Provisional

Application No. 61/218,590 entitled "Group IV Catalyst Supported by O, N, C Ligands For Olefin Polymerization" filed June 19, 2009, the entire contents of which are incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

[0002] The present invention relates to olefin polymerization, and, more particularly, to novel olefin polymerization catalysts and methods of olefin polymerization using said catalysts.

2. Description of the Related Art

[0003] One of the ultimate challenges in the field of polymer synthesis is the ability to control material properties by manipulating molecular weight, molecular weight distribution, and stereochemistry.

[0004] Over the years, a number of homogeneous olefin polymerization catalysts have been developed that offer remarkable control over polymer stereochemistry. While metallocene catalysts dominated the olefin polymerization field from the early 1980's to the mid-1990's, a new generation of "non-metallocene" catalysts has since become the major focus. In particular, advances in living olefin polymerization have allowed access to new polyolefin architectures, specifically block copolymers, that exhibit promising material properties. One recent class of catalysts to emerge are the Ci -symmetric pyridylamidohafnium dialkyl complexes developed by Dow Chemical ^® Company and Symyx ^® Technologies which feature a cyclometalated Hf-C _aryl bond (T. R. Boussie, et al., Angew. Chem., Int. Ed. 2006, 45, 3278-3283; R.D.J. Froese, et al., Am. Ch Je.m. Soc. 2007, 129, 7831-7840; C. Zuccaccia, et al., A Jm. . Chem. Soc. 2008, 130, 10354-10368). In addition to producing high molecular weight polymer, these catalysts can exhibit high levels of isoselectivity, thermal stability, and activity for olefin polymerization. Investigations into the catalyst activation mechanism have shown that a single 1,2-insertion of an olefin into the Hf-C _Ary i bond results in a seven-membered metallacycle bearing an sp ³ -hybridized carbon donor atom that supports the active metal center rather than participating in further olefin insertion (R.D.J. Froese, et al., A Jm.. Chem. Soc. 2007, 129, 7831-7840). It has also been demonstrated that C ₃ -symmetric precatalysts activated with B(C ₆ F ₅ ) ₃ furnish isotactic polypropylene ("iPP") via an enantiomorphic site-control enchainment mechanism, suggesting that the observed isoselectivity results from formation of a Ci -symmetric catalyst through 1,2-insertion of an olefin into the Hf-C _Aryl bond (G. J. Domski, et al., Macromolecules 2007, 40, 3510-3513.)- It has further been shown that precatalysts supported by an sp ³ -C donor could be generated by insertion of a ligand-appended alkene into the Hf-C bond of a neutral pyridylamidohafnium trimethyl complex to produce pyridylamidohafnium dimethyl six-membered metallacycle complexes as a racemic mixture of diastereomers (G. J. Domski, et al., Chem. Commun. 2008, 46, 6137-6139). Activation of these precatalysts with B(C ₆ F ₅ ) ₃ promoted the living and isoselective polymerization of propylene.

[0005] With the advent of homogeneous stereospecific olefin polymerization catalysts, the control over polyolefin microstructure can now be rationalized by the appropriate choice of a metallocene or non-metallocene transition metal catalyst precursor. While the stereospecific polymerization of vinyl-monomers can give rise to only two microstructures of maximum order {i.e. isotactic and syndiotactic), the cyclopolymerization of dienes can give rise to four microstructures of maximum order.

[0006] Because cyclopolymers include both cis and trans stereochemistry of the rings and the relative stereochemistry between the rings, the microstructure is significantly more complicated than linear polymers derived from simple vinyl-monomers. Due to its relatively lower cost, the cyclopolymerization of 1,5-hexadiene has been extensively more studied than the cyclopolymerization of 1,6-heptadiene. Coates and Waymouth carried out a full microstructural analysis of poly(methylene-1,3-cyclopentane) ("PMCP") derived from the cyclopolymerization of 1,5-hexadiene (G.W. Coates, R.M. Waymouth, Am. J C. hem. Soc. 1993, 115, 91-98). The formation of PMCP from 1,5-hexadiene is assumed to proceed via a two-step reaction mechanism; olefin insertion followed by cyclization. The tacticity is described as the relative stereochemistry of the first stereocenter of every ring, which is independent of the cisltrans stereochemistry. Thus, the tacticity of the polymer is influenced by the enantiofacial selectivity of the catalyst on the first insertion step whereas the cisltrans stereochemistry of the ring is determined by the diastereoselectivity of the cyclization step. [0007] The cyclopolymerization of 1,5-hexadiene was first reported using heterogeneous catalysts. Marvel and Stille first reported on the cyclopolymerization of 1,5- hexadiene using catalysts derived from TiCl ₄ in combination with 'Bu ₃ Al or Et ₃ Al (CS. Marvel, J.K. Stille, J. Am. Chem. Soc. 1958, 80, 1740-1744). Makowski later reported on this system and both groups noted incomplete cyclization and low activities (H. S. Makowski, et al., J. Polym. Sci., Part A 1964, 2, 1549). Cheng and co-workers more recently reported on the use of TiCVEt ₂ AlCl for the cyclopolymerization of 1,5-hexadiene (H.N. Cheng, N.P. Khasat, J. Appl. Polym. Sci. 1988, 35, 825-829). Analysis of the polymer microstructure by ¹³ C NMR spectroscopy revealed complete cyclization and a 1:1 ratio of cis- and trans- cyclopentane rings in the polymer. Further investigation into the cyclopolymerization of 1,5- hexadiene has centered on the use of homogeneous catalysts.

[0008] Resconi and Waymouth reported on the first use of metallocene catalysts

(CpZrCl ₂ and Cp* ₂ ZrCl ₂ ) activated with methylaluminoxane ("MAO") for the cyclopolymerization of 1,5-hexadiene (L. Resconi, RJ. Waymouth, J. Am. Chem. Soc. 1990, 112, 4953-4954; L. Resconi, et al., J. Macromol. ScL, Chem. 1991, A28, 1225-1234). Polymerization of 1,5-hexadiene at room temperature or below with CpZrCl ₂ ZMAO affords PMCP with a high selectivity for trans-cyclopentane rings. In contrast, polymerization of 1,5-hexadiene with Cp* ₂ ZrCl ₂ /MAO furnishes PMCP with a predominance of cis- cyclopentane rings. The difference in selectivity is attributed to the preference of the growing polymer chain to adopt a pseudo-chair transition state in the cyclization step for CpZrCl ₂ , which leads to a trans ring. The more sterically encumbered Cp* ₂ ZrCl ₂ forces the polymer chain to adopt a twist-boat conformation in the transition state that leads to the formation of a cis ring. Both catalysts showed no selectivity for the insertion step, thus leading to atactic polymers.

[0009] The first enantioselective cyclopolymerization of 1,5-hexadiene was reported by Coates and Waymouth (G.W. Coates, R.M. Waymouth, J. Am. Chem. Soc. 1991, 113, 6270-6271). Using an optically pure catalyst derived from (-)-(R)- ethylenebis(tetrahydroindenyl)zirconium (R )-binaphtholate and MAO, optically active PMCP was obtained that showed a positive molar optical rotation. Cyclopolymerization of 1,5- hexadiene with the opposite enantiomer afforded PMCP with an opposite and equal molar optical rotation value. The optically active polymers contained approximately 68% trans rings. Of the four possible microstructures of maximum order, only trans -isota.ctic PMCP is chiral. Based on this, the observation of optical activity provides proof that the polymers obtained had an isotactic microstructure. This observation was later supported by a full microstructural analysis of the PMCP revealing an enantiofacial selectivity of 91% (G.W. Coates, R.M. Waymouth, J. Am. Chem. Soc. 1993, 115, 91-98). [0010] Other metallocene derivatives have also been studied for the cyclopolymerization of 1,5-hexadiene. Baird and co-workers reported on the use of Cp*TiMe ₃ activated with B(C ₆ F ₅ ) ₃ in the presence of 1,5-hexadiene that resulted in PMCP of high molecular weight (M _w = 400 - 500 kg/mol) and broad polydispersities (MJM _n = 4 - 5) (D. Jeremic, et al., J. Organomet. Chem. 1995, 497, 143-147). Analysis of the polymers by ¹³ C{ ¹ H} NMR spectroscopy revealed the PMCP generally contained transxis ratios of 1.4:1 to 1: 1. However, the resonances were sufficiently broadened that no tacticity information could be obtained. Mukaiyama and co-workers reported on a C ₂ -symmetric heterotrinuclear zirconium iron metallocene complex (M. Mitani, et al., Chem. Lett. 1995, 905-906). Upon activation with MAO in the presence of 1,5-hexadiene, PMCP was obtained with greater than 91% trans-cyclopentane rings. However, no information regarding the tacticity of the polymer was reported. Schaverien has reported on the use of a dimeric yttrium hydride catalyst supported by Cp* and aryloxide ligands for the cyclopolymerization of 1,5-hexadiene (CJ. Schaverien, Organometallics 1994, 13, 69-82). Reaction of the dimeric yttrium hydride catalyst supported by Cp* and aryloxide ligands with neat 1,5-hexadiene afforded PMCP containing a slight selectivity for trans-cyclopentane rings (transxis ratio 1.0:0.8). Again, no information regarding the tacticity was disclosed.

[0011] The use of non-metallocene catalysts for the cyclopolymerization of 1,5- hexadiene has been the focus of more recent reports. In 2000 Sita and co-workers reported the use of amidinate-based zirconium catalysts activated with [PhNMe ₂ H][B(C ₆ F ₅ ) ₄ ] for the cyclopolymerization of 1,5-hexadiene (K.C. Jayaratne, et al., J. Am. Chem. Soc. 2000, 122, 10490-10491). All the catalysts showed selectivity for the formation of trans-cyclopentane rings with an increase in steric bulk resulting in an increase in trans content. The structure of the catalyst was found to influence the isotactic content of the PMCP. Furthermore, these catalyst systems were found to be living, enabling the formation of block copolymers with PMCP and poly(l-hexene) blocks that undergo microphase separation.

[0012] KoI and co-workers have recently reported on the synthesis of diastereomerically pure zirconium complexes supported by chiral Salan ligands for the cyclopolymerization of 1,5-hexadiene (A. Yeori, et al., J. Am. Chem. Soc. 2006, 128, 13062- 13063; A. Yeori, et al., Macromolecules 2007, 40, 8521-8523). Activation of the chiral Salan ligands used in that study with B in the presence of 1,5-hexadiene furnished PMCP with trans -isotactic rings. The polymers were found to be optically active and use of the other diastereomer of chiral Salan ligands produced polymers with opposite optical rotation values.

[0013] Exquisite control over the polymer microstructure in the polymerization of vinyl-monomers by Ziegler-Natta catalysts has been achieved with a wide variety of catalysts throughout the past several decades. Yet, in the polymerization of dienes such as 1,5- hexadiene, only one of the possible four microstructures of maximum order have been reported to date. Highly isotactic catalysts for the polymerization of vinyl-monomers tend to give trans-isotactic PMCP due to the lower energy pseudo-chair conformational transition state for ring closure. Few syndioselective catalysts have been investigated in the polymerization of 1,5-hexadiene. However, of those reported for the polymerization of 1,5- hexadiene, an entirely different microstructure is obtained. For example, Hustad and Coates reported on the polymerization of 1,5-hexadiene with a fluorinated bis(phenoxyimine) titanium complex activated with MAO (P.D. Hustad, G.W. Coates, Am. C Jh. em. Soc. 2002, 124, 11578-11579). The polymer was found to contain methylene- 1,3-cyclopentane ("MCP") units (63%) as well as 3-vinyl tetramethylene ("VTM") units (37%). Doi and co- workers reported that syndioselective V(acac) ₃ catalysts produce nearly identical poly(1,5- hexadiene) (Y. Doi, et al., Makromol Chem., Macromol. Chem. Phys. 1989, 190, 643-651). The formation of MCP units is easily explained from 1 ,2-insertion followed by 1,2- cyclization. However, an initial 2,1-insertion of 1,5-hexadiene followed by a 1 ,2-cyclization forms a strained cyclobutane species. After a ß -alkyl elimination, the 3 -VTM unit is generated. Thus, microstructures of cis- or trans-syndiotactic PMCP remain elusive. To date the formation of c-iissotactic PMCP has remained elusive as well.

[0014] Despite these many recent advances in olefin polymerization, there is a continued need for both new, highly-active olefin polymerization catalysts and for new polyolefin architectures with desirable microstructures and material properties.

SUMMARY OF THE INVENTION

[0015] It is therefore a principal object and advantage of the present invention to provide new olefin polymerization catalysts and new polyolefin architectures. [0016] It is another object and advantage of the present invention to provide new olefin polymerization catalysts with high levels of activity, isoselectivity, and thermal stability.

[0017] It is yet another object and advantage of the present invention to provide microstructures of cis-isotactic poly(methylene- 1,3-cyclopentane). [0018] It is a further object and advantage of the present invention to provide cis- isotactic poly (methylene- 1 , 3 -cyclohexane) .

[0019] Other objects and advantages of the present invention will in part be obvious, and in part appear hereinafter.

[0020] In accordance with the foregoing objects and advantages, the present invention provides an olefin polymerization catalyst comprising the following formula:

where Ri through R ₄ and R ₁₀ through R ₁₃ can include, but is not limited to, hydrogen, a halogen, a nitro group, a hydrocarbyl group, a substituted hydrocarbyl group, an alkoxide group, an alkylsulfonyl group, and a fluorocarbyl group; R ₁₅ and R ₁₆ can include, but is not limited to, a halogen, an alkoxide group, a hydrocarbyl group, and a substituted hydrocarbyl group; R ₅ through R ₉ , R ₁₄ , and R ₁₇ through R ₁₉ can include, but is not limited to, hydrogen, a hydrocarbyl group, and a substituted hydrocarbyl group; and M is a Group IV metal. According to one embodiment of the present invention, M is hafnium, zirconium, or titanium. [0021] The olefin can be any olefin known, described, or suggested in the art, including but not limited to ethylene, 1-hexene, propylene, 1,5-hexadiene, and 1,6- heptadiene, among many others.

[0022] A second aspect of the present invention provides an olefin polymerization catalyst comprising the following formula:

where R ₂ , R ₄ through R ₆ , and R ₈ through R ₁₃ are each hydrogen; R ₁ , R ₃ , and R ₇ can include, but is not limited to, hydrogen, a halogen, a nitro group, a hydrocarbyl group, a substituted hydrocarbyl group, an alkoxide group, an alkylsulfonyl group, and a fluorocarbyl group; R ₁₄ through R ₁₉ can include, but is not limited to, hydrogen, a hydrocarbyl group, and a substituted hydrocarbyl group; and M is a Group IV metal. According to one embodiment, R1 is 1-adamantyl.

[0023] A third aspect of the present invention provides a method of olefin polymerization using the following olefin polymerization catalyst:

where Ri through R ₄ and R ₁₀ through R ₁₃ can include, but is not limited to, hydrogen, a halogen, a nitro group, a hydrocarbyl group, a substituted hydrocarbyl group, an alkoxide group, an alkylsulfonyl group, and a fluorocarbyl group; R ₁₅ and R ₁₆ can include, but is not limited to, a halogen, an alkoxide group, a hydrocarbyl group, and a substituted hydrocarbyl group; R ₅ through R ₉ , R ₁₄ , and R ₁₇ through R ₁₉ can include, but is not limited to, hydrogen, a hydrocarbyl group, and a substituted hydrocarbyl group; and M is a Group IV metal. According to one embodiment of the present invention, M is hafnium, zirconium, or titanium. [0024] A fourth aspect of the present invention provides a method of olefin polymerization using one of the olefin polymerization catalysts described herein, or its equivalent. According to one embodiment of the present invention, the olefin is 1-hexene, propylene, 1,5-hexadiene, 1,6-heptadiene, ethylene, 4-methyl-1-pentene, among many others, or a combination of one or more olefins.

[0025] A fifth aspect of the present invention provides a method of olefin polymerization using one of the olefin polymerization catalysts described herein, or its equivalent, with an activator. According to one embodiment of the present invention, the activator can include, but is not limited to, trityl tetrakis(pentafluorophenyl)borate, N,N- dimethylanilinium tetrakis(pentafluorophenyl)borate, tris(pentafluorophenyl)borane, and an aluminum activator, among others.

[0026] A sixth aspect of the present invention provides a method of olefin polymerization using one of the olefin polymerization catalysts described herein, or its equivalent, further comprising a metal alkyl capable of transmetallating with the olefin polymerization catalyst.

[0027] A seventh aspect of the present invention provides a process for preparing an olefin block polymer comprising the step of combining a first olefin with the olefin polymerization catalyst of claim 1 under polymerization reaction conditions such that an olefin polymer is formed.

[0028] An eighth aspect of the present invention provides a process for preparing an olefin heteropolymer, comprising the steps of: (i) combining a first olefin with the olefin polymerization catalyst of claim 1 under polymerization reaction conditions such that a first olefin block is formed; and (2) adding a second olefin to form a second olefin block such that the first and second blocks form a heteropolymer. According to one embodiment of the present invention, the first and/or second olefin can be ethylene, propylene, or a combination of the two. [0029] A ninth aspect of the present invention provides a process for preparing an olefin heteropolymer in which the process further includes an activator combined with the first olefin and the olefin polymerization catalyst of claim 1. According to one embodiment of the present invention, the activator is tris(pentafluorophenyl)borane. According to another embodiment, the mixture includes an activator such as trityl tetrakis (pentafluorophenyl)borate , N,N-dimethylanilinium tetrakis (pentafluorophenyl)borate, or tris(pentafluorophenyl)borane, among many others. According to yet another embodiment, the process occurs at one of either about 0ºC or 25 ºC.

BRIEF DESCRIPTION OF THE DRAWINGS

[0030] The present invention will be more fully understood and appreciated by reading the following Detailed Description in conjunction with the accompanying drawings, in which:

[0031] Fig. 1 is a graphical representation of a method of vinyl group ligand- appended phenoxyamine synthesis according to one embodiment of the present invention; [0032] Fig. 2 is a graphical representation of a method of rac-Og ¹ ZrBn ₂ -a, rac-

Og ¹ ZrBn ₂ -b, rac-Og ¹ HfBn ₂ -a, and TOC-Og ¹ HfBn ₂ ^ synthesis according to one embodiment of the present invention;

[0033] Fig. 3 is a graphical representation of a method of the formation of rac-

Og ² TiBn according to one embodiment of the present invention;

[0034] Fig. 4 is the molecular structure of TOC-Og ¹ HfBn ₂ -a according to one embodiment of the present invention;

[0035] Fig. 5 is the molecular structure of rac-Og ¹ HfBn ₂ -b according to one embodiment of the present invention;

[0036] Fig. 6 is the molecular structure of rac-Og ¹ ZrBn ₂ -a according to one embodiment of the present invention;

[0037] Fig. 7 is the molecular structure of rac-Og ¹ ZrBn ₂ -b according to one embodiment of the present invention;

[0038] Fig. 8 is the molecular structure of rac-Og ² TiBn according to one embodiment of the present invention;

[0039] Fig. 9 is the molecular structure of rac-Lig (CH ₂ ) ₂ TiBn according to one embodiment of the present invention;

[0040] Fig. 10 is a graphical representation of the interconversion of the diastereomers rac-Og ¹ MBn ₂ -a,b according to one embodiment of the present invention; [0041] Fig. 11 is a graphical representation of the interconversion of the confomers rac-Lig ¹ MBn ₂ -a,b via ring-flip of six-membered metallacycle;

[0042] Fig. 12 is an Oak Ridge Thermal Ellipsoid Plot Program ("ORTEP") plot of rac-Lig ¹ HfBn ₂ -a according to one embodiment of the present invention, with thermal ellipsoids are drawn at the 40% probability level;

[0043] Fig. 13 is an ORTEP plot of rac-Lig ¹ ZrBn ₂ -a according to one embodiment of the present invention, with thermal ellipsoids are drawn at the 40% probability level;

[0044] Fig. 14 is an ORTEP plot of rac-Lig ² TiBn according to one embodiment of the present invention, with thermal ellipsoids are drawn at the 40% probability level;

[0045] Fig. 15 is is a graphical representation of the reaction of rac-Lig TiBn with ethylene according to one embodiment of the present invention;

[0046] Fig. 16 is a graph of M _n and MJM _n versus polymer yield for 1-hexene polymerization at 0ºC catalyzed by rac-Lig ¹ HfBn ₂ -a,b/B(C ₆ F ₅ ) ₃ according to one embodiment of the present invention;

[0047] Fig. 17 is the ¹³ C( ¹ H) NMR spectrum of poly (1-hexene) furnished from rac-

Lig ¹ HfBn2-a,b/B(C ₆ F ₅ )3 at 0ºC (150 MHz, 1,1,2,2-C ₂ D ₂ Cl ₄ , 135°C) according to one embodiment of the present invention;

[0048] Fig. 18 is a graph of M _n (●) and MJM _n (■) versus polymer yield for propylene polymerization at 0ºC catalyzed by rac-Lig ¹ ZrBn ₂ -a,b/B(C ₆ F ₅ ) ₃ according to one embodiment of the present invention;

[0049] Fig. 19 is the ¹³ C{ ¹ H} NMR spectrum of iPP-block-PEP synthesized using rac-Lig ¹ ZrBn ₂ -a,b/B(C ₆ F ₅ ) ₃ at 0ºC (150 MHz, 1,1,2,2-C ₂ D ₂ Cl ₄ , 135°C) according to one embodiment of the present invention;

[0050] Fig. 20 is a graphical representation of the cyclopolymerization of 1,5- hexadiene (x = 0) and 1,6-heptadiene (x = 1) to cis-isotactic poly (methylene- 1,3- cyclopentane) ("PMCP") and poly(methylene-1,3-cyclohexane) ("PMCH") by rac-

Lig ¹ ZrBn ₂ -a,b and rac-Lig ¹ HfBn ₂ -a,b according to one embodiment of the present invention;

[0051] Fig. 21 is the ¹³ C( ¹ H) NMR spectra for: (a) PMCP and (b) PMCH prepared with at 0ºC (150 MHz, 1,1,2,2-C ₂ D ₂ Cl ₄ , 135°C) according to one embodiment of the present invention;

[0052] Fig. 22 is the molecular structure of microstructures of maximum order for

PMCP (x = 0) and PMCH (x = 1); [0053] Fig. 23 is the ¹³ C( ¹ H) NMR spectra of C ₄ , ₅ for PMCP prepared with (a)

Cp ₂ ZrCl ₂ /MAO and (b) at 25°C (150 MHz, 1,1,2,2-C ₂ D ₂ Cl ₄ , 135 ºC); and

[0054] Fig. 24 is a ¹³ C{ ¹ H} NMR spectrum of iPP produced by rac-Lig ¹ ZrBn ₂ - a,b/B(C ₆ F ₅ ) ₃ at 0 ºC (150 MHz, 1,1,2,2-C ₂ D ₂ Cl ₄ , 135°C) according to one embodiment of the present invention.

DETAILED DESCRIPTION

[0055] The present invention provides new tridentate phenoxyamine catalysts supported by an sp ³ -C donor via insertion of a ligand-appended alkene into a neutral group IV alkyl complex. According to one embodiment, the phenoxyamine ligands were prepared through a Mannich reaction between N-methyl-1-(2-vinylphenyl)methanamine, paraformaldehyde, and a 2,4-disubstituted phenol. Metalation of the resultant phenoxyamine ligands with tetrabenzyl group IV precursors afforded new sp ³ -C bound six-membered metallacycle complexes as a mixture of two diastereomers arising from intramolecular insertion of the ligand-appended alkene into the neutral group IV tribenzyl precursor. [0056] Using an embodiment of the system, six-membered metallacycle complexes rac-Lig ¹ ZrBn ₂ -a,b and rac-Lig ¹ HfBn ₂ -a,b were obtained from reaction of the vinyl-appended ligand with tetrabenzylzirconium (ZrBn ₄ ) or tetrabenzylhafnium (HfBn ₄ ). The rac- Lig ¹ HfBn ₂ -a,b/B(C ₆ F ₅ ) ₃ metallacycle complexes promoted the living and isoselective polymerization of 1-hexene at 0ºC, while the rac-Lig ¹ ZrBn ₂ -a,b/B(C ₆ F ₅ ) ₃ complexes catalyzed the living and isoselective polymerization of propylene at 0ºC. In yet another embodiment, complexes derived from rac-Lig ¹ HfBn ₂ -a,b and rac-Lig ¹ ZrBn ₂ -a,b also served as highly active cyclopolymerization catalysts for 1,5-hexadiene which furnished poly(methylene-1,3-cyclopentane) with a predominance of cis-cyclopentane rings. Lastly, cyclopolymerization of 1 ,6-heptadiene with rac-Lig ¹ HfBn ₂ -a,b/B(C ₆ F ₅ ) ₃ produced poly(methylene-1,3-cyclohexane) with a nearly perfect cis-isotactic microstructure. [0057] The six-membered sp ³ -C bound phenoxyamine titanium complex underwent further reaction through toluene elimination to form an unusual tetrahedral titanium complex, rac-Lig ² TiBn, featuring a bound ligand-appended alkene. Although rac-Lig ² TiBn is inactive for olefin polymerization upon benzyl abstraction, treatment with ethylene leads to the formation of the stable titanacyclopentane complex rac-Lig (CH ₂ ) ₂ TiBn. [0058] The present invention also provides a method for the synthesis of a diblock copolymer featuring an isotactic polypropylene semicrystalline block and poly(ethylene-co- propylene) ("PEP") amorphous block. Utilizing the living nature of this catalyst, the iPP- block-PEP diblock copolymer was synthesized via sequential monomer addition using rac- Lig ¹ ZrBn ₂ -a,b/B(C ₆ Fs) ₃ at 0ºC according to one embodiment of the present invention. [0059] According to yet another embodiment of the present invention, complexes derived from from rac-Lig ¹ HfBn ₂ -a,b and rac-Lig ¹ ZrBn ₂ -a,b formed highly active cyclopolymerization catalysts for 1,5-hexadiene furnishing PMCP with a predominance of α ^' s-cyclopentane rings, while complexes derived from rac-Lig ¹ HfBn ₂ -a,b showed a higher propensity towards ds-ring closure than those derived from rac-Lig ¹ ZrBn ₂ -a,b. The enantiofacial selectivity for the insertion step of 1,5-hexadiene polymerization proceeds with a relative high selectivity for isotactic enchainment, and the obtained PMCPs represent the first report of a highly ds-isotactic microstructure.

[0060] The present invention also provides a system for the cyclopolymerization of

1,6-heptadiene with rac-Lig ¹ HfBn ₂ -a,b/B(C ₆ F ₅ ) ₃ to produce PMCH with a nearly perfect cis- isotactic microstructure.

[0061] 1-hexene and propylene polymerization behavior of rac-Lig ¹ ZrBn2-a,b and rac-Lig ¹ HfBn ₂ -a,b

[0062] To synthesize a new class of olefin polymerization catalysts incorporating an ancillary sp ³ -C donor into the ligand framework, ligands bearing pendant vinyl group functionality were prepared. Vinyl-appended phenoxyamine ligands were initially targeted in hopes of preparing tridentate group IV complexes arising from insertion of the alkene into the metal trialkyl precursors. The phenoxyamine ligands were prepared through a Mannich reaction (as described in E. Y. Tshuva, et al., Tetrahedron Lett. 2001, 42, 6405-6407) between N-methyl-1-(2-vinylphenyl)methanamine, paraformaldehyde, and a 2,4-disubstituted phenol, as shown in FIG. 1. Metalation of the resultant phenoxyamine ligands with tetrabenzyl group IV precursors afforded new sp ³ -C bound six-membered metallacycle complexes as a mixture of two diastereomers arising from intramolecular insertion of the ligand-appended alkene into the neutral group IV tribenzyl precursor, as shown in FIG. 2. In the case of zirconium (rac- LIg ¹ ZrB n ₂ -a,b) and hafnium (rac- Lig ¹ HfBn ₂ -a,b), highly active and isoselective 1-hexene and propylene polymerization catalysts were formed upon activation. The six-membered sp ³ - C bound phenoxyamine titanium complex underwent further reaction through toluene elimination to form an unusual tetrahedral titanium complex termed rac-Lig ² TiBn and featuring a bound ligand-appended alkene, as shown in FIG. 3. This complex was found to be inactive for olefin polymerization upon activation, however, reaction with ethylene leads to the formation of a titanacyclopentane complex.

[0063] Detailed characterizations of the 1-hexene and propylene polymerization behavior of both rac-Lig ¹ ZrBn ₂ -a,b and rac-Lig ¹ HfBn ₂ -a,b under a number of activation conditions were performed and are reported herein. The rac-Lig ¹ ZrBn ₂ -a,b/B(C ₆ F ₅ ) ₃ furnished isotactic polypropylene ([m ⁴ ] = 0.76) in a living manner at 0ºC with high activity, while isotactic poly (1-hexene) was obtained with living behavior from rac-Lig ¹ HfBn ₂ - a,b/B(C ₆ F ₅ ) ₃ at 0 ºC. Employing rac-Lig ¹ ZrBn ₂ -a,b/B(C ₆ F ₅ ) ₃ , an iPP-block-PEP ("PEP" = poly(ethylene-co-propylene)) diblock copolymer was prepared. The results presented herein illustrate intramolecular vinyl group insertion for ligand- appended phenoxyamines upon metalation with tetrabenzyl group IV metal precursors as a unique method to generate sp ³ -C bound precatalysts for olefin polymerization. [0064] Methods and Materials

[0065] Example 1

[0066] General Methods of Complex Syntheses

[0067] All manipulations of air- and/or water-sensitive compounds were carried out under dry nitrogen using a Braun UniLab drybox or standard Schlenk techniques. ¹ H NMR spectra of ligands and complexes were recorded using Varian Unitylnova (400, 500, or 600 MHz) spectrometers and were referenced versus residual non-deuterated solvent shifts. ¹³ C{ ¹ H} NMR spectra of ligands and complexes were recorded on a Varian Unitylnova (500 MHz) spectrometer equipped with a ¹ H/BB switchable probe equipped with Z-axis pulsed field gradient. ¹³ C{ ¹ H} NMR spectra of polymers were recorded using a Varian Unitylnova (600 MHz) spectrometer equipped with a 10 mm broadband probe operating at 135 ºC and referenced versus residual non-deuterated solvent shifts. The gradient selected COSY, HSQCAD, gradient selected HMBCAD, and ROESY spectra were recorded on a Varian Unitylnova (600 MHz) spectrometer operating at 599.757 MHz for ¹ H observation using a Varian inverse ¹ H-( ¹³ C, ¹⁵ N) triple-resonance probehead with triple-axis gradients. NMR data were acquired with the pulse sequences supplied in Vnmrj 2.1B/Chempack 4.1 and were processed and analyzed using the MestReNova 5.3 software package (2008, Mestrelab Research S. L.). Gradient selected COSY spectra were acquired using the gCOSY sequence with a spectral width of 4.3-4.6 kHz. A total of 512 points were collected in the indirectly detected dimension with 1 scan and 4k points per increment. The resulting matrices were zero filled to 8k x 512 complex data points and 0° sinebell window functions were applied in both dimensions prior to Fourier transformation. ROESY spectra were acquired using the ROESY sequence with a spectral width of 4.3-4.6 kHz. A total of 200 complex points were collected in the indirectly detected dimension with 8 scans and 0.15 s acquisition time per increment. The resulting matrices were zero filled to 2k x 2k complex data points and unshifted Gaussian window functions were applied in both dimensions prior to Fourier transformation. The multiplicity-edited adiabatic HSQC spectrum was acquired with the HSQCAD sequence. Spectral widths were 4.3-4.6 kHz and 25-30 kHz in ¹ H and ¹³ C dimensions, respectively. A total of 256 complex points were collected in the indirectly detected dimension with 4 scans and 0.15 s acquisition time per increment. The resulting matrices were zero filled to 2k x 2k complex data points and an unshifted Gaussian window function was applied in the ¹ H dimension prior to Fourier transformation. Gradient selected adiabatic HMBC spectra were acquired in phase sensitive mode with the gHMBCAD sequence optimized for 8 Hz couplings. Spectral widths were 4.3-4.6 kHz and 25-30 kHz in ¹ H and ¹³ C dimensions, respectively. A total of 500-600 complex points were collected in the indirectly detected dimension with 4 scans and 2048 points per increment. The resulting matrices were zero filled to 2k x 4k complex data points and shifted sinebell window functions were applied in the ¹ H dimension prior to Fourier transformation. The polymer samples were dissolved in l,1,2,2-tetrachloroethane-d2 in a 5 mm O. D. tube, and spectra were collected at 135 ºC. For quantitative ¹³ C{ ¹ H} analysis, the polymer samples were dissolved in l,1,2,2-tetrachloroethane-d ₂ in 10 mm O. D. tubes and the spectra were collected with inverse gated decoupling using the TYCO-25 decoupling sequence, a 30° excitation pulse width, 2.0 s acquisition time, and 10 s relaxation delay. Molecular weights (M _n and M _w ) and polydispersities (M _w /M _n ) were determined by high temperature gel permeation chromatography (GPC). Analyses were performed with a Waters Alliance GPCV 2000 GPC equipped with a Waters DRI detector and viscometer. The column set (four Waters HT 6E and one Waters HT2) was eluted with 1,2,4-trichlorobenzene containing 0.01 wt. % di-tert- butylhydroxytoluene (BHT) at 1.0 mL/min at 140 ºC. Data were calibrated using monomodal polyethylene standards in the case of PP or monomodal polystyrene standards in the case of poly(l-hexene) (from Polymer Standards Service). Polymers were usually placed in a 140 ºC oven for 24 h prior to molecular weight measurements. Polymer melting points (T _m ) and glass transition temperatures (T _g ) were measured by differential scanning calorimetry (DSC) using a TA Instruments QlOOO calorimeter equipped with an automated sampler. Analyses were performed in crimped aluminum pans under nitrogen and data were collected from the second heating run at a heating rate of 10 °C/min from -100 to 200ºC, and processed with TA Q series software. Mass spectral analyses were conducted at the School of Chemical Sciences Mass Spectrometry Laboratory at the University of Illinois at Urbana- Champaign or they were acquired using a JEOL GCMate II mass spectrometer operating at 3000 resolving power for high resolution measurements in positive ion mode and an electron ionization potential of 70 eV. Samples were introduced via a GC inlet using an Agilent HP 6890N GC equipped with a 30 m (0.25 μm i.d.) HP-5ms capillary GC column. The carrier gas was helium with a flow rate of 1 mL/min. Samples were introduced into the GC using a split/splitless injector at 230ºC with a split ratio of 10:1. [0068] Example 2

[0069] Materials

[0070] Toluene and pentane were purified over columns of alumina and copper (Q5) prior to use. Diethyl ether (Et ₂ O) was purified over a column of alumina and degassed by three freeze -pump thaw cycles and stored under nitrogen. Benzene-^ was distilled from sodium benzophenone ketyl under nitrogen, degassed, and stored over 4A molecular sieves in the glovebox under nitrogen. Propylene (Airgas, research purity) was purified over columns (40 cm inner diameter x 120 cm long) of BASF catalyst R3-12, BASF catalyst R3-11, and 4A molecular sieves. 2-Bromostyrene, anhydrous N,N-dimethylformamide (DMF), ethyl acetate (EtOAc), hexanes, methylene chloride (CH ₂ Cl ₂ ), magnesium sulfate (MgSO ₄ ), methylamine (2.0 M in methanol), sodium borohydride (NaBH ₄ ), paraformaldehyde, and 2,4-di-tert- butylphenol were purchased from Aldrich or Mallinkrodt and used as received. Tetrabenzylzirconium (ZrBn ₄ ), magnesium turnings, tris(pentafluorophenyl)borane (B(C ₆ F ₅ ) ₃ ), trityl tetrakis(pentafluorophenyl)borate ([Ph ₃ C][B(C ₆ Fs) ₄ ]), and NN- dimethylanilinium tetrakis(pentafluorophenyl)borate ([PhNMe ₂ H][B(C ₆ F ₅ ) ₄ ]) were purchased from Strem and used as received. 2-Vinylbenzaldehyde, 2-(l-adamantyl)-4-methylphenol, tetrabenzylhafnium (HfBn ₄ ), and tetrabenzyltitanium (TiBn ₄ ) were prepared from standard literature procedures.

[0071] N- Methyl- l-(2-vinylphenyl)methanamine was produced as follows.

Following a modified procedure of Dale (WJ. Dale, et al., J. Org. Chem. 1961, 26, 2225- 2227), 2-vinylbenzaldehyde was prepared via Grignard formation of 2-bromostyrene (6.0 mL, 46 mmol) with magnesium turnings (1.5 g, 61 mmol) in Et ₂ O followed by reaction with DMF (5.4 mL, 70 mmol) to yield 4.2 g (68%) following column chromatography (2% EtOAc/hexanes). The 2-vinylbenzaldehyde (2.0 g, 15 mmol) was charged to a 100 mL round bottom flask containing a magnetic stir bar and methanol (15 mL). The reaction vessel was sealed with a rubber septum and methylamine (11 mL of a 2.0 M solution in methanol, 22 mmol) was added at room temperature via syringe. The reaction was stirred for one hour after which it was cooled to 0ºC and NaBH ₄ (1.1 g, 29 mmol) was slowly added over ten minutes. The reaction was allowed to come to room temperature over two hours and water (50 mL) and CH ₂ Cl ₂ (50 mL) were added. The organic layer was separated and the aqueous layer was extracted with CH ₂ Cl ₂ (2 x 30 mL). The combined organics were washed with brine (50 mL), dried over MgSO ₄ , filtered, and concentrated via rotary evaporation. The residue was dried in vacuo to yield 2.09 g (94%) of a light yellow liquid. ¹ H NMR (400 MHz, C ₆ D ₆ ) δ 7.49 - 7.45 (m, 1H, ArH), 7.25 - 7.18 (m, 1Η, ArH), 7.17 - 7.15 (m, 1Η, ArH), 7.14 - 7.07 (m, 2Η, ArH and CH=CH ₂ ), 5.59 (dd, J = 17.5, 1.5, 1H, CH=CH ₂ ), 5.18 (dd, J = 11.0, 1.5, 1Η, CH=CH ₂ ), 3.55 (s, 2Η, ArCH ₂ ), 2.21 (s, 3Η, NHCH ₃ ), 0.56 (s, 1Η, NHCH ₃ ). ¹³ C{ ¹ H} NMR (125 MHz, C ₆ D ₆ ) δ 138.38, 137.78, 135.48, 129.86, 128.18, 127.83, 126.35, 115.62, 54.47, 36.69. MS-EI (m/z): 147.1 (M ⁺ ). HRMS-EI (m/z): calcd for Ci ₀ H ₁₃ N, 147.1048; found, 147.1049.

[0072] 2-(l-Adamantyl)-4-methyl - 6 - ((methyl(2-vinylbenzyl)amino)methyl) phenol

(Lig ¹ ) was produced as follows. A 20 mL scintillation vial was charged with 2-(l- adamantyl)-4-methylphenol (1.36 g, 5.61 mmol), N-methyl-1-(2-vinylphenyl)methanamine (0.820 g, 5.55 mmol), and paraformaldehyde (0.260 g, 8.59 mmol) in 8 mL of methanol. The vial was capped, sealed with electrical tape and heated at 65 ºC for 48 hours. After cooling, the solvent was removed in vacuo and the residues were purified by flash chromatography (2% EtOAc/hexanes) to give 1.21 g (54%) of a colorless oil that solidified upon standing into a white solid. ¹ H ΝMR (500 MHz, C ₆ D ₆ ) δ 10.58 (s, 1H, OH), 7.39 (d, J = 7.1, 1Η, ArH), 7.13 (s, 1Η, ArH), 7.10 - 6.95 (m, 4Η, ArH and CH=CH ₂ ), 6.62 (s, 1H, ArH), 5.56 (dd, J = 17.3, 1.3, 1Η, CH=CH ₂ ), 5.29 (dd, J = 10.9, 1.3, 1Η, CH=CH ₂ ), 3.35 (s, 2Η, ArCH ₂ NCH ₃ ), 3.25 (s, 2H, ArCH ₂ NCH ₃ ), 2.45 (d, J = 2.4, 6H, Ad-CH ₂ ), 2.31 (s, 3Η, ArCH ₃ ), 2.14 (s, 3Η, Ad-CH), 1.97 - 1.75 (m, 6Η, Ad-CH ₂ ), 1.81 (s, 3Η, ArCH ₂ NCH ₃ ). ¹³ C( ¹ H) NMR (125 MHz, C ₆ D ₆ ) δ 155.45, 138.47, 137.26, 135.07, 134.95, 131.48, 128.68, 128.27, 127.87, 127.70, 127.58, 126.82, 122.78, 116.68, 62.50, 59.47, 41.30, 40.96, 38.02, 37.59, 30.11, 21.51. MS- ESI (m/z): 402.2 (M ⁺ ). HRMS-ESI (m/z): calcd for C ₂₈ H ₃₆ NO, 402.2797; found, 402.2800. Anal. calc. for C ₂₈ H ₃₅ NO: C, 83.74; H, 8.78; N, 3.49. Anal, found C, 83.70; H, 8.78; N, 3.34. [0073] The 2,4-Di-tert-butyl - 6 - ((methyl(2-vinylbenzyl)amino)methyl) phenol

(Lig ) was produced as follows. A 20 mL scintillation vial containing a magnetic stir bar was charged with 2,4-di-tert-butylphenol (0.85 g, 4.1 mmol), N-methyl-1-(2- vinylphenyl)methanamine (0.61 g, 4.1 mmol), paraformaldehyde (0.19 g, 6.2 mmol) and 8 mL methanol. The vial was capped, sealed with electrical tape and heated at 65 ºC for 48 hours. Upon cooling to room temperature, the product crystallized to yield 0.80 g (53%) of a white crystalline solid after drying in vacuo. ¹ H ΝMR (500 MHz, C ₆ D ₆ ) δ 10.73 (s, 1H, OH), 7.51 (s, 1Η, ArH), 7.38 (d, J = 7.9, 1Η, ArH), 7.13 - 7.08 (m, 1Η, ArH), 7.07 - 7.00 (m, 2Η, ArH), 6.97 (dd, J = 17.7, 10.9, 1Η, CH=CH ₂ ), 6.93 (s, 1H, ArH), 5.53 (dd, J = 17.3, 1.3, 1Η, CH=CH ₂ ), 5.26 (dd, J = 10.9, 1.3, 1Η, CH=CH ₂ ), 3.39 (s, 2Η, NCH ₂ ), 3.26 (s, 2Η, NCH ₂ ), 1.81 (s, 3Η, NCH ₃ ), 1.70 (s, 9Η, ArCCH ₃ ), 1.38 (s, 9Η, ArCCH ₃ ). ¹³ C( ¹ H) NMR (125 MHz, C ₆ D ₆ ) δ 155.23, 141.16, 138.49, 136.42, 135.08, 134.92, 131.38, 128.68, 128.28, 126.82, 124.09, 123.61, 122.26, 116.70, 62.74, 59.41, 41.03, 35.71, 34.72, 32.37, 30.39. MS-ESI (m/z): 366.3 (M ⁺ ). HRMS-ESI (m/z): calcd for C ₂₅ H ₃₆ NO, 366.2797; found, 366.2795. Anal, calc. for C ₂₅ H ₃₅ NO: C, 82.14; H, 9.65; N, 3.83. Anal, found C, 81.87; H, 9.81; N, 4.10. [0074] Example 3

[0075] Synthesis of rac-Lig ¹ HfBn ₂ -a,b

[0076] In a glovebox, a Schlenk adapted tube was charged with HfBn ₄ (0.43 g, 0.78 mmol) in 5 mL of dry toluene. To this was charged 2-(l-adamantyl)-4-methyl-6-((methyl(2- vinylbenzyl)amino) methyl)phenol (0.31 g, 0.78 mmol) in 5 mL of dry toluene. The reaction vessel was sealed and heated at 60ºC for one hour. After cooling, the volatiles were removed in vacuo and the residues were taken up in dry pentane. The volatiles were removed again in vacuo and the residues were dried for 24 hours to yield 0.53 g (79%) of white powdery solid that was stored at -30 ºC in the glovebox freezer. Single crystals of suitable quality for structural determination via X-ray crystallography were grown from slow diffusion of pentane into a saturated toluene solution at -30ºC over the course of several weeks. The ¹ H and ¹³ C( ¹ H) NMR data are tabulated below in Table 1 ("nd" = could not be determined). The resonances were assigned with the aid of COSY, HMBCAD, HSCQAD, and ROESY NMR experiments. The structure of rac-Lig ¹ HfBn ₂ -a corresponding to Table 1 is shown in FIG. 4, and the structure of rac-Lig ¹ HfBn ₂ -b corresponding to Table 1 is shown in FIG. 5. [0077] Table 1. NMR Data for rac-Lig^fflnz-^b

[0078] Example 4

[0079] Synthesis Of TOC-Ug ¹ ZrBn ₂ -^b

[0080] In a glovebox, a Schlenk adapted tube was charged with ZrBn ₄ (0.46 g, 1.0 mmol) in 5 mL of dry toluene. To this was charged 2-(l-adamantyl)-4-methyl-6-((methyl(2- vinylbenzyl)amino)methyl) phenol (0.40 g, 1.0 mmol) in 5 mL of dry toluene. The reaction vessel was sealed and stirred for 30 minutes at room temperature. The volatiles were then removed in vacuo and the residues were taken up in dry pentane. The volatiles were removed again in vacuo and the residues were dried for 24 hours to yield 0.66 g (86%) of a thermally sensitive yellow-orange powdery solid that was stored at -30ºC in the glovebox freezer. Single crystals of suitable quality for structural determination via X-ray crystallography were grown from a saturated pentane solution at 20ºC over the course of several weeks. The ¹ H and ¹³ C{ ¹ H} NMR data obtained in toluene-d ₈ at -10ºC are tabulated below in Table 2 ("nd" = could not be determined). The resonances were assigned with the aid of COSY, HMBCAD, HSQCAD, and ROESY NMR experiments. The structure of rac-Lig ¹ ZrBn ₂ -a corresponding to Table 2 is shown in FIG. 6, and the structure of rac-Lig ¹ ZrBn ₂ -b corresponding to Table 2 is shown in FIG. 7.

[0082] Example 5

[0083] Synthesis of rac-Lig ² TiBn.

[0084] In a glovebox, a Schlenk adapted tube was charged with TiBn ₄ (0.12 g, 0.29 mmol) in 3 mL of dry toluene. To this was charged 2,4-di-tert-butyl-6-((methyl(2- vinylbenzyl)amino)methyl)phenol (0.11 g, 0.29 mmol) in 3 mL of dry toluene. The reaction vessel was sealed and heated to 60ºC for one hour. After cooling, the volatiles were removed in vacuo and the residues were taken up in dry pentane. The volatiles were removed again in vacuo and the residues were dried for 24 hours to yield 0.11 g (63%) of a glassy black solid. Single crystals of suitable quality for structural determination via X-ray crystallography were grown from a saturated pentane solution at -30ºC over the course of several weeks. The ¹ H and ¹³ C{ ¹ H} NMR data obtained in C ₆ D ₆ at room temperature are tabulated below in Table 3. The resonances were assigned with the aid of COSY, HMBCAD, and HSQCAD NMR experiments. The structure of rac-Lig ² TiBn corresponding to Table 3 is shown in FIG. 8. [0085] Table 3. NMR Data for rac-Lig ² TiBn.

[0086] Example 6

[0087] Synthesis of rac-Lig ² (CH ₂ ) ₂ TiBn.

[0088] In a glovebox, a Schlenk adapted tube was charged with TiBn ₄ (0.13 g, 0.32 mmol) in 3 mL of dry toluene. To this was charged 2,4-di-tert-butyl-6-((methyl(2- vinylbenzyl)amino)methyl)phenol (0.12 g, 0.32 mmol) in 3 mL of dry toluene. The reaction vessel was sealed and heated to 60ºC for one hour to afford a black solution rac-Lig ² TiBn. After cooling, the reaction was pressurized with 1 atm of ethylene causing an immediate color change to a dark red solution. The reaction was stirred overnight and the solution was filtered to remove residual polyethylene that had formed (~ 60 mg). The volatiles were then removed in vacuo and the residues were taken up in dry pentane. The volatiles were removed again in vacuo and the residues were dried for 24 hours to yield 0.12 g (61%) of a powdery dark red solid. The ¹ H and ¹³ C( ¹ H) NMR data obtained in C ₆ D ₆ at room temperature are tabulated below in Table 4. The resonances were assigned with the aid of COSY, HMBCAD, HSQCAD, and ROESY NMR experiments. The structure of rac-Lig ² (CH ₂ ) ₂ TiBn corresponding to Table 4 is shown in FIG. 9. [0089] Table 4. NMR Data for rac-Lig ² (CH ₂ ) ₂ TiBn.

[0090] Example 7

[0091]

[0092] To a solution of rac-Lig ¹ Hffln ₂ -a,b or rac-Ug ¹ ZrBn ₂ -a,b (~25 mg) in C ₆ D ₆ which had been stored in a J. Young NMR tube was added several drops of MeOH, the tube

99 was shaken vigorously and the solution became colorless almost immediately. The volatiles were removed in vacuo. The residue was taken up in C ₆ D ₆ and flashed through a small plug of Celite to isolate 2-(l-adamantyl)-4-methyl-6-((methyl(2-(3- phenylpropyl)benzyl)amino)methyl)phenol. ¹ H NMR (400 MHz, C ₆ D ₆ ) δ 10.82 (s, 1H, Ar- OH), 7.24 - 7.12 (m, 4Η, ArH), 7.12 - 7.04 (m, 4Η, ArH), 7.01 (t, J = 7.2, 2Η, ArH), 6.64 (s, 1Η, ArH), 3.34 (s, 2Η, NCH ₂ ), 3.19 (s, 2Η, NCH ₂ ), 2.64 - 2.56 (m, 2Η, ArCH ₂ ), 2.53 (t, J = 7.5, 2Η, ArCH ₂ ), 2.46 (s, 6Η, Ad-CH ₂ ), 2.32 (s, 3Η, ArCH ₃ ), 2.14 (s, 3, Ad-CH), 1.97 - 1.77 (m, 6Η, Ad-CH ₂ ), 1.85 (s, 3Η, NCH ₃ ) _, 1.74 (t, J = 7.7, 2Η, ArCH ₂ CH ₂ CH ₂ Ar). ¹³ C{ ¹ H} NMR (125 MHz, C ₆ D ₆ ) δ 155.52, 142.78, 142.05, 137.25, 135.55, 131.33, 130.14, 129.22, 129.02, 128.68, 127.83, 127.73, 127.58, 126.68, 126.51, 122.87, 62.64, 59.27, 41.32, 41.06, 38.00, 37.61, 36.35, 33.66, 32.31, 30.11, 21.51. MS-ESI (m/z): 494.3 (M ⁺ ). HRMS-ESI (m/z): calcd for C ₃₅ H ₄₄ NO, 494.3423; found, 494.3416. Anal. calc. for C ₃₅ H ₄₃ NO: C, 85.14; H, 8.78; N, 2.84. Anal, found C, 84.90; H, 8.39; N, 2.56. [0093] Example 8

[0094] Polymer Syntheses

[0095] For 1-hexene polymerization at 25°C, in a glovebox B(C ₆ F ₅ ) ₃ (5.1 mg, 10 mmol) was placed into a scintillation vial along with 9 mL of toluene and 2 mL of 1-hexene. To this solution was added 10 mmol) dissolved in 1 mL of toluene. The polymerization was allowed to proceed for 10 minutes after which time the vial was removed from the glovebox and the polymerization was terminated by the addition of MeOH. The volatiles were removed in vacuo to furnish poly (1-hexene) (0.30 g, 23%). The same procedure was followed for 1-hexene polymerization using [Ph ₃ C][B(C ₆ F ₅ ) ₄ ] and [PhNMe ₂ H] [B (C ₆ Fs) ₄ ] as activators and also for the analogous rac-Lig ¹ ZrBn ₂ -a,b complex. [0096] For 1-hexene polymerization at 0ºC, in a glovebox B(C ₆ Fs) ₃ (5.1 mg, 10 mmol) was placed into a Schlenk adapted tube along with 19 mL of toluene and 3 mL of 1- hexene. The reaction was sealed, removed from the glovebox and equilibrated in an ice bath at 0ºC for 15 minutes. To this solution was added rac-Lig ¹ HfBn ₂ -a,b (8.5 mg, 10 mmol) dissolved in 1 mL of toluene in a gas tight syringe under an active nitrogen flow. The polymerization was allowed to proceed for the desired period of time after which time the polymerization was terminated by the addition of MeOH. The volatiles were removed in vacuo to furnish poly (1-hexene). A similar procedure was followed for 1-hexene polymerization using the analogous rac-Lig ¹ ZrBn ₂ -a,b complex except the reaction was carried out in 3 mL of toluene. Table 5 is a living plot of 1-hexene polymerization data for rac-Lig ¹ HfBn ₂ -a,b/B(C6F5)3 at 0ºC with the following general conditions: rac-Lig ¹ HfBn ₂ -a,b

= 20 mmol, [Hf]/[B(C ₆ Fs) ₃ ] = 1.0, 20 mL toluene, 3.0 mL 1-hexene. The average turnover frequency ("TOF") is in mol l-hexene/(mol Hf- h). The M _n , M _n theo, MJM _n were determined using gel permeation chromatography in 1,2,4-C ₆ H ₃ Cl ₃ at 140ºC versus polystyrene standards.

[0097] Table 5. Living plot 1-hexene polymerization data for rac-Lig ¹ HfBn ₂ - a,b/B(C ₆ F ₅ ) ₃ at 0ºC.

[0098] For propylene polymerization at 25°C, in a glovebox a 6 oz. flat-bottomed

Lab-Crest pressure reaction vessel (Andrews Glass Co.) was charged with 25 mL of toluene and B(C ₆ F ₅ ) ₃ (5.1 mg, 10 mmol). The reactor was sealed, and the solution was saturated under a constant feed of propylene (30 psig) for 5 minutes with continuous stirring in a 25 ºC water bath. Polymerization was initiated by injection of 5 mL of a solution of rac- Lig ¹ HfBn ₂ -a,b (8.5 mg, 10 mmol) dissolved in toluene. The polymerization was allowed to proceed under a constant feed of propylene for 10 minutes and terminated by the addition of MeOH with simultaneous venting and discontinuation of the propylene feed. The polymer was precipitated in copious MeOH and allowed to stir overnight; it was collected via filtration and dried to constant weight in vacuo at 60ºC. The same procedure was followed for propylene polymerization using [Ph ₃ C][B(C ₆ Fs) ₄ ] and [PhNMe ₂ H][B(C ₆ Fs) ₄ ] as activators and also for the analogous rac-Lig ¹ ZrBn ₂ -a,b complex.

[0099] For propylene polymerization at 0ºC, a stock solution of zirconium precatalyst was prepared by dilution of 200 mmol (153 mg) of rac-Lig ^] ZrBn ₂ -a,b to 10 mL in a volumetric flask with toluene. A stock solution of B(C ₆ Fs) ₃ (102 mg, 200 mmol) was prepared in an identical manner. In the glovebox, a 6 oz. flat-bottomed Lab-Crest pressure reaction vessel (Andrews Glass Co.) was charged with 27 mL of toluene and 1.5 mL of the B(C ₆ Fs) ₃ solution. The reactor was sealed and equilibrated at 0ºC for 30 minutes. The solution was then saturated under a constant feed of propylene (30 psig) for 10 minutes with continuous stirring. Polymerization was initiated by injection of 1.5 mL of the rac- Lig ^] ZrBn ₂ -a,b solution. The polymerization was allowed to proceed under a constant feed of propylene for the desired period of time and terminated by the addition of MeOH with simultaneous venting and discontinuation of the propylene feed. The polymer was precipitated in copious MeOH and allowed to stir overnight; it was collected via filtration and dried to constant weight in vacuo at 60 ºC. Similar procedures were followed for propylene polymerization using [Ph ₃ C][B(C ₆ F ₅ ) ₄ ] and [PhNMe ₂ H][B(C ₆ F ₅ ) ₄ ] as activators and also for the analogous rac-Lig ¹ HfBn ₂ -a,b complex. Table 6 is a living plot of propylene polymerization data for rac-Lig ¹ ZrBn ₂ -a,b/B(C ₆ Fs) ₃ at 0ºC with the following general conditions: 30 mmol of rac-Lig ¹ ZrBn ₂ -a,b in toluene (1.5 mL) was added to a propylene - saturated solution of activator (28.5 mL of toluene; [Zr]/[B(C ₆ Fs) ₃ ] = 1.0) at 0ºC. The average turnover frequency ("TOF") is in mol propylene/(mol Zr-h). The M _n , M _n theo, MJM _n were determined using gel permeation chromatography in 1,2,4-C ₆ H ₃ Cl ₃ at 140ºC versus polystyrene standards.

[00100] Table 6. Living plot propylene polymerization data for

[00101] Results

[00102] Example 9

[00103]

[00104] Reaction of Lig ¹ with HfBn ₄ in C ₆ D ₆ at 25°C immediately provided a phenoxyaminehafnium dibenzyl complex arising from intramolecular insertion of the pendant vinyl moiety in a 2,1 -fashion. The ¹ H NMR spectrum showed complete disappearance of vinyl resonances and the selective formation of one major diastereomer. Heating the C ₆ D ₆ solution at 60ºC for one hour led to a 55:45 ratio of a mixture of diastereomers (rac-

Lig ¹ HfBn ₂ -a,b). Prolonged reaction at 25°C (10-11 days) resulted in the same ratio of diastereomers, which suggests that an equilibrium exists for the mixture of diastereomers in solution with possible interconversion proceeding through ß-hydride elimination and reinsertion of the opposite face of the newly formed alkene, as shown in FIG. 10. The reaction of Lig ¹ with ZrBn ₄ in toluene-d ₈ at 25 ºC resulted in the immediate formation of a diastereomeric mixture (58:42 ratio) of rac Lig ¹ ZrB n ₂ -a,b as monitored by ¹ H NMR spectroscopy. It is reasonable to suggest that rapid interconversion of the diastereomers occurs in solution at 25 ºC, which is in complete contrast to that observed with the hafnium complex.

[00105] Broad peaks for many of the methylene resonances appear in the room- temperature ¹ H NMR spectrum in toluene-d ₈ for both complexes making assignment difficult, but upon cooling to -10ºC, some of the methylene resonances can be resolved as doublets. In the ¹ H NMR spectrum of rac-Lig ¹ HfBn ₂ -a,b, resonances for the meta-H's on the phenolate ring in between the Ar-CH ₃ and Ar-CH ₂ N substituents appear as two isolated singles at 6.37 (major) and 6.22 (minor) ppm. These diagnostic resonances are consistent with the formation of rαc-Lig ¹ HfBn ₂ -a,b as a mixture of diastereomers. In the ¹ H NMR spectrum of rac- Lig ¹ ZrBn ₂ -a,b, the distinguishing resonances consistent with the formation of a mixture of diastereomers are the methylene H's on the N-CH ₂ substituent attached to the lower phenyl ring system, which appear as two isolated doublets at 3.58 (major) and 3.50 (minor) ppm. The ¹³ C( ¹ H) ΝMR spectrum of both complexes reveal 74 resonances, 37 corresponding to each diastereomer. The resonances for each carbon of rac-Lig ¹ HfBn ₂ -a,b and rac-Lig ¹ ZrBn ₂ - a,b were fully assigned with the aid of COSY, ¹ H- ¹³ C HMBC, ¹ H- ¹³ C HSQC, and ROESY ΝMR experiments. In the ROESY ΝMR spectra at -10 ºC, both rac-Lig ¹ HfBn ₂ -b and rac- Lig ¹ ZrBn ₂ -b exhibit exchange peaks with a third confomer, which could potentially arise from a ring-flip of the six-membered metallacycle giving a possibility of four total conformers, as shown in FIG. 11. No such exchange was observed for rac-Lig ¹ HfBn ₂ -a and rac-Lig ¹ ZrBn ₂ -a at this temperature. Furthermore, the third confomer is undetectable in the ¹ H NMR spectra. Methanolysis of either diastereomeric mixture afforded a phenoxyamine with a 3-phenylpropyl group bound to the carbon atom at the 2-position of the benzyl moiety consistent with intramolecular 2,1 -insertion of the ligand-appended alkene into the M-C _A i _ky i (M = Hf, Zr) bond for the neutral benzyl compound.

[00106] Single crystals of rac-Lig ¹ HfBn ₂ -a suitable for structural determination via X- ray crystallography were grown from slow diffusion of pentane into a saturated toluene solution over several weeks at -30ºC to afford a colorless crystalline solid. The solid state molecular structure of rac-Lig ¹ HfBn ₂ -a, shown in FIG. 12, revealed that the coordination geometry about hafnium is best described as distorted trigonal bipyramidal with C(41) and 0(1) occupying the axial positions (O(l)-Hf(l)-C(41) = 159.54(7)°). Crystals of rac-Lig ^] Zr- a suitable for X-ray diffraction were grown from a saturated pentane solution over several weeks at 25 °C to provide a thermally sensitive orange crystalline solid. The solid state molecular structure of rac- Lig ¹ ZrBn ₂ -a, shown in FIG. 13, was nearly isostructural to rac- Lig ¹ HfBn ₂ -a and revealed a coordination geometry around zirconium best described as distorted trigonal bipyramidal with C(8) and 0(1) occupying the axial positions (0(I)-Zr(I)- C(8) = 158.22(13)°). Inspection of the extended unit cell of both complexes revealed the presence of only one diastereomer. [00107] Example 9

[00108] Synthesis of rac-Lig ² TiBn

[00109] Having shown that 1 reacts with HfBn ₄ and ZrBn ₄ to furnish complexes arising from the intramolecular 2,1-insertion of the pendant vinyl moiety in the ligand framework, the reaction with TiBn ₄ was next investigated. However, suitable crystals for X- ray diffraction could not be obtained from the reaction of 1 with TiBn ₄ so the reaction of a similar phenoxyamine ligand, 2, with TiBn ₄ was investigated. Monitoring the reaction of 2 with TiBn ₄ in C ₆ D ₆ at 25 °C by ¹ H NMR spectroscopy initially showed a tribenzylphenoxyaminetitanium complex and one equivalent of toluene from phenol deprotonation. Over the next 3 hours, slow insertion of the pendant vinyl moiety resulted in a mixture of diastereomers, similar to the hafnium and zirconium complexes. Continued reaction at 25 °C over 2 additional days resulted in liberation of a second equivalent of toluene, which gave rise to a phenoxyaminetitanium alkene complex (rac-Lig ² TiBn) as a racemic mixture of only one diastereomer as evidenced from the presence of only one N- methyl resonance and two tert-butyl resonances in the ¹ H ΝMR spectrum. The ¹³ C( ¹ H) ΝMR spectrum revealed 31 resonances, which is also consistent with the formation of rac- Lig ² TiBn as a racemic mixture of a single diastereomer. The resonances for each carbon were fully assigned with the aid of COSY, ¹ H- ¹³ C HMBC, and ¹ H- ¹³ C HSQC ΝMR experiments. It is possible that toluene elimination can only occur from one of the six- membered metallacycles, which may explain the formation of only one diastereomer. Νegishi and co-workers have proposed that Cp ₂ Zr(n-Bu) ₂ will undergo ß-hydride elimination with loss of butene to give Cp ₂ Zr(H)(n-Bu), which reductively eliminates butane to generate free Cp ₂ Zr (E. Νegishi, et al., Tetrahedron Lett. 1986, 27, 2829-2832). A similar mechanism could be involved in the formation of rac-Lig ² TiBn as a titanium(II) alkene complex. Initialß-hydride elimination would generate a ligand- appended alkene that could coordinate to the titanium(IV) metal center followed by reductive elimination of toluene to generate rac- Lig TiBn. Interestingly, Buchwald and co-workers have reported that warming Cp ₂ Zr(W-Bu) ₂ in the presence of PMe ₃ yields Cp ₂ Zr(l-butene)(PMe ₃ ), which suggests that butane is eliminated from Cp ₂ Zr(n-Bu) ₂ before butene is lost (S. L. Buchwald, et al., J. Am. Chem. Soc. 1987, 109, 2544-2546). Therefore, direct toluene loss to give rac-Lig TiBn as a titanium(II) alkene complex is also plausible.

[00110] Single crystals of rac-Lig ² TiBn as a black crystalline solid suitable for X-ray diffraction were grown from a saturated pentane solution over several weeks at -30ºC. The solid state molecular structure, shown in FIG. 14, revealed a distorted tetrahedral coordination geometry about titanium. From the short Ti(l)-C(25) and Ti(l)-C(26) distances (2.510(5) A and 2.699(5) A respectively) and significant bending of the phenyl ring towards the metal center (C(25)-C(24)-Ti(l) = 85.3(3)°), it is apparent that the benzyl substituent is bound in an η ³ -fashion. This binding mode has been observed for neutral electron-deficient zirconium complexes (M. Wiecko, et al., Dalton Trans. 2005, 2147-2150). Furthermore, the short Ti(l)-C(7) distance (2.560(5) A) and significant bending of the phenyl ring adjacent the titanium-bound alkene towards the metal center (C(7)-C(31)-Ti(l) = 89.3(3)°), suggests that there is incoordination of this substituent as well. The pi-bonding of the benzyl sigma ligand in addition to the pi-bonding of the supported tridentate ligand is a result of the electron-deficient character of the titanium metal center. The short C(31)-C(32), Ti(l)-C(31), and Ti(l)-C(32) distances (1.436(7) A, 2.118(4) A, and 2.148(4) A respectively) are similar to that reported for η -olefin complexes of titanium supported by aryloxide ligands and bis(pentamethylcyclopentadienyl)(ethylene)titanium(II). Notably, the C(31)-C(32) bond distance shows significant lengthening from free alkene which is indicative of substantial electron back-donation from the titanium metal center. Based on comparisons with other structural data, rac-Lig ² TiBn appears to be intermediate along the continuum between the titanium(II) alkene adduct and a titanium(IV) metallacyclopropane. [00111] Example 10

[00112] Reaction of rac-Lig ² TiBn with Ethylene

[00113] While, as expected, rac-Lig ² TiBn proved to be unreactive towards olefin polymerization upon benzyl abstraction, titanacyclopropanes have been shown to be versatile reagents for many fundamental organic and organometallic transformations. Bercaw and co- workers have shown that treatment of bis(pentamethylcyclopentadienyl)(ethylene)titanium(II) with ethylene results in an equilibrium mixture containing the newly formed Cp* ₂ Ti metallacyclopentane complex, however, it was not sufficiently stable to allow isolation (S. A. Cohen, et al., J. Am. Chem. Soc. 1983, 105, 1136-1143). Treatment of a black solution of rac-Lig ² TiBn with one atmosphere of ethylene in C ₆ D ₆ at 25 ºC resulted in an immediate color change to dark red. The ¹ H NMR spectrum indicated quantitative conversion of rac-Lig ² TiBn to a titanacyclopentane complex, rac-Lig ² (CH ₂ ) ₂ TiBn. Prolonged exposure to ethylene yields trace amounts of polyethylene, but no change in the resonances of rac-Lig ² (CH ₂ ) ₂ TiBn, which suggests a trace impurity is responsible. A large scale reaction was carried out to isolate rac-Lig ² (CH ₂ ) ₂ TiBn as a stable, dark red solid. Single crystals suitable for structural analysis by X-ray diffraction could not be obtained for racLig ² (CH ₂ ) ₂ TiBn due to its high degree of solubility, even in non-polar solvents. However, characterization of rac- Lig ² (CH ₂ ) ₂ TiBn by ¹ H, ¹³ C( ¹ H), COSY, ¹ H- ¹³ C HMBC, ¹ H- ¹³ C HSQC, and ROESY NMR spectroscopy allowed three dimensional structural determination of the product in solution, which, on the basis of the solid state molecular structure of rac-Lig ² TiBn, is consistent with pericyclic migratory insertion of ethylene and formation of the product as a racemic mixture of only one diastereomer, as shown in FIG. 15. The resonances for the methine and methylene carbons attached to the titanium in the metallacyclopentane ring appear at 102.48 and 95.56 ppm in the ¹³ C( ¹ H) NMR spectrum, which is consistent with Ti-C chemical shifts observed in titanacyclopentane compounds supported by aryloxide ligands. The remaining methine and methylene carbon resonances in the titanacyclopentane ring appear at 46.80 and 39.93 ppm in the ¹³ C( ¹ H) NMR spectrum. In the ROESY NMR spectrum, no exchange peaks are observed for the methylene protons resulting from the pericyclic migratory insertion of ethylene at temperatures up to 50ºC. Taken together, this supports the view of rac Lig ² (CH ₂ ) ₂ TiBn as a titanium(IV) metallacyclopentane complex and not a titanium(II) bis-alkene complex. [00114] Example 11

[00115] 1-Hexene Polymerization Behavior

[00116] The 1-hexene polymerization behavior of the catalysts derived from rac-

Lig ¹ HfBn ₂ -a,b and rac-Lig ¹ ZrBn ₂ -a,b were investigated. The results are compiled in Table 7, with the following general conditions: Complex ("CpIx") = 10 mmol, and [Cplx]/[B] = 1.0, 10 mL toluene, 2.0 mL 1-hexene, except for rac-Lig ¹ ZrBn ₂ -a,b, which is 20 mmol, [Cplx]/[B] = 1.0, 3.0 mL toluene, 3.0 mL 1-hexane. The average turnover frequency ("TOF") is in mol l-hexene/(mol Cplx-h). The M _n , M _n theo, MJM _n were determined using gel permeation chromatography in 1,2,4-C ₆ H ₃ Cl ₃ at 140 ºC versus polystyrene standards. Addition of rac-Lig ¹ Hffln ₂ -a,b to a solution of [Ph ₃ C][B(C ₆ Fs) ₄ ] and 1-hexene (1:1:1600) in toluene at 25°C led to the formation of 1.22 g of poly (1-hexene) (91% conversion) in 10 minutes. The polymer possessed a molecular weight (M _n ) of 178 kg/mol and a relatively narrow molecular weight distribution (MJM _n = 1.48). Similar molecular weights and molecular weight distributions were obtained upon activation with B(C ₆ Fs) ₃ and [PhNMe ₂ H][B(C ₆ Fs) ₄ ] at 25 ºC, albeit with lower activity. Upon noticing the molecular weight distribution of the poly (1-hexene) prepared using rac-Lig ¹ HfBn ₂ -a,b/B(C ₆ Fs) ₃ was quite narrow (Mw/M _n = 1.31), the polymerization behavior of this catalyst at lower reaction temperatures was next investigated. Activation of rac-Lig ¹ HfBn ₂ -a,b with B(C ₆ Fs) ₃ at 0ºC in toluene resulted in the formation of 0.45 g of poly (1-hexene) (33% conversion) in 30 minutes. The obtained polymer had an M _n of 238 kg/mol and an extremely narrow molecular weight distribution (MJM _n = 1.08), which suggests the polymerization is living under these reaction conditions. A linear increase in molecular weight versus poly( 1-hexene) yield at 0ºC further illustrated the living behavior of rac-Lig ¹ HfBn ₂ -a,b/B(C ₆ Fs) ₃ , as shown in FIG. 16 (which is a plot of M _n (•) and MJM _n (■) versus polymer yield for 1-hexene polymerization at 0ºC catalyzed by rac-Lig ¹ HfBn ₂ -a,b/B(C ₆ Fs) ₃ . The M _n and MJM _n values were determined by gel permeation chromatography in 1,2,4-C ₆ H ₃ Cl ₃ at 140 ºC (polystyrene standards)). In all cases, the obtained molecular weights were five times higher than that predicted based on the assumption of one chain per metal center (M _n theo), which indicates that approximately 20% of the metal centers are active in the polymerization. Analysis of the poly (1-hexene) microstructure by ¹³ C( ¹ H) NMR spectroscopy revealed that the polymer was regioregular and highly isotactic; the spectrum showed no signals corresponding to stereoerrors, as shown in FIG. 17. The high degree of stereoselectivity observed for this catalyst is likely due to the chiral structure of rac-Lig ¹ HfBn ₂ -a,b. Therefore, rac-Lig ¹ HfBn ₂ -a,b/B(C ₆ Fs) ₃ represents a new, highly isoselective catalyst for living 1-hexene polymerization. Interestingly, a polymerization with rac-Lig ¹ HfBn ₂ -b was carried out, which is cleanly synthesized upon initial metalation of Lig ¹ with HfBn ₄ , and obtained nearly identical polymerization results upon activation with B(C ₆ Fs) ₃ at 0ºC as was obtained with rac-Lig ¹ HfBn ₂ -a,b/B(C ₆ Fs) ₃ . This suggests that upon activation of the diastereomeric mixture of rac-Lig ¹ HfBn ₂ -a,b a similar active species is generated for each separate diastereomer.

[00117] Table 7. 1-Hexene polymerization data for rac-Lig ¹ HfBn ₂ -a,b and rac-

Lig ¹ ZrBn ₂ -a,b.

[00118] The 1-hexene polymerization behavior of rac-Lig ¹ ZrBn ₂ -a,b was also investigated. Activating rac-Lig ¹ ZrBn ₂ -a,b with [Ph ₃ C][B(CoFs) ₄ ] in the presence of 1- hexene (1: 1:1600) and toluene at 25 ºC led to the formation of 0.47 g of poly (1-hexene) (35% conversion) in 10 minutes. The polymer (M _n = 67 kg/mol) exhibited a narrow molecular weight distribution (MJM _n = 1.91) indicative of a single-site polymerization catalyst. Activation with B(C ₆ F ₅ ) ₃ and [PhNMe ₂ H][B(C ₆ Fs) ₄ ] at 25°C gave rise to poly(l-hexene)s with similar molecular weights and molecular weight distributions, but lower activity was observed. Although none of the molecular weight distributions were sufficiently narrow to indicate any potential living behavior, rac-Lig ¹ ZrBn ₂ -a,b was screened under the same conditions that gave living behavior for rac-Lig ¹ HfBn ₂ -a,b. Interestingly, activation of rac- Lig ¹ ZrBn ₂ -a,b with B(C ₆ F ₅ ) ₃ at 0ºC in toluene (1-hexene: toluene = 1:5 V/V) led only to a trace of polymer in 90 minutes. However, increasing the concentration (1-hexene: toluene = 1:1 V/V) gave rise to the formation of 0.93 g of poly (1-hexene) (46% conversion) in 30 minutes. The polymer displayed an M _n of 105 kg/mol but the molecular weight distribution (MJM _n = 1.63) was too broad to indicate a living polymerization catalyst. Analysis of the poly (1-hexene) microstructure via ¹³ C{ ¹ H} NMR spectroscopy revealed that the polymer was also regioregular and highly isotactic (see Appendix). In stark contrast to the polymerization behavior of rac-Lig ¹ HfBn ₂ -a,b/B(C ₆ F ₅ ) ₃ at 0ºC, the zirconium congener (rac-Lig ¹ ZrBn ₂ -a,b) displayed no characteristics of living 1-hexene polymerization behavior. [00119] Example 11

[00120] Propylene Polymerization Behavior

[00121] The propylene polymerization behavior of rac-Lig ¹ HfBn ₂ -a,b and rac-

Lig ¹ ZrB n ₂ -a,b at 25 ºC was investigated. The results are compiled in Table 8, with the following general conditions: 10 μmol of the complex in toluene (5 mL) was added to a propylene-saturated solution of activator (25 mL of toluene; [Cplx]/[B] = 1.0) at 25 ºC. The average turnover frequency ("TOF") is in mol propylene/(mol Cplx-h). The M _n , M _n theo, MJM _n were determined using gel permeation chromatography in 1,2,4-C ₆ H ₃ Cl ₃ at 140ºC versus polyethylene standards. The [m ⁴ ] was determined by integration of the methyl region of the ¹³ C( ¹ H) NMR spectrum, and Tg (ºC) and Tm (°C)e were determined using differential scanning calorimetry (second heating). Activation of rac-Lig ¹ HfBn ₂ -a,b with [Ph ₃ C][B(C ₆ Fs) ₄ ] at 25 ºC furnished polypropylene (PP) with an average turnover frequency (TOF) of 9,700 h ^-1 and the polymer possessed an M _n of 106 kg/mol (MJM _n = 1.88). Analysis of the PP microstructure by ¹³ C( ¹ H) NMR spectroscopy revealed that it was isotactic ([m ⁴ ] = 78%) and regioregular with stereoerrors indicating an enantiomorphic site-control enchainment mechanism (mmmr.mmrr.mrrm pentads = 2:2:1). Similar molecular weights and molecular weight distributions were obtained upon activation with B(C ₆ F ₅ ) ₃ and [PhNMe ₂ H][B(C ₆ F ₅ ) ₄ ] at 25°C, with activity trends mirroring those observed for 1-hexene polymerization.

[00122] Table 8. Propylene polymerization data for rac-Lig ¹ HfBn ₂ -a,b and rac-

Lig ¹ ZrBn ₂ -a,b at 25ºC.

[00123] In light of the living behavior observed for 1-hexene polymerization at OºC, the propylene polymerization behavior of rac-Lig ¹ HfBn ₂ -a,b at OºC was investigated. The results are compiled in Table 9, with the following general conditions: 10 μmol of the complex in toluene (5 mL) was added to a propylene-saturated solution of activator (25 mL of toluene; [Cplx]/[B] = 1.0) at 25°C, except for rac-Lig ¹ HfBn ₂ -^b and rac-Lig ¹ Hffln ₂ -a,b with 20 μmol of the complex ([Cplx]/[B] = 1.0), and rac-Lig ¹ ZrBn ₂ -a,b with 30 μmol of the complex ([Cplx]/[B] = 1.0). The average turnover frequency ("TOF') is in mol propylene/(mol Cplx-h). The M _n , M _n theo, MJM _n were determined using gel permeation chromatography in 1 ,2,4-C _O H ₃ CI ₃ at 140ºC versus polyethylene standards.. The [m ⁴ ] was determined by integration of the methyl region of the ¹³ C( ¹ H) NMR spectrum, and T _g (ºC) and T _m (ºC) were determined using differential scanning calorimetry (second heating). Activation of rac-Lig ¹ HfBn ₂ -a,b with [Ph ₃ C][B(C6F ₅ ) ₄ ] at 0ºC in the presence of propylene furnished isotactic polypropylene with a TOF of 35,400 h ^-1 . The higher activity can be attributed to the higher propylene concentration when the polymerization is conducted at 0ºC. The obtained polymer had an M _n of 238 kg/mol and MJM _n of 1.72 with an [m ⁴ ] = 83%. Interestingly, activation with [PhNMe ₂ H][B(C ₆ F ₅ ) ₄ ] or B(C ₆ F _S ) ₃ at 0ºC resulted in much less active catalysts (TOF = 4,200 and 3,200 h ^-1 respectively) and gave iPP of much lower molecular weight (M _n = 89 and 95 kg/mol respectively). Furthermore, living behavior was not observed under any activation condition, which contrasts the living behavior observed for 1-hexene polymerization with rac-Lig ¹ HfBn ₂ -a,b/B(C ₆ Fs) ₃ at 0ºC.

[00124] Table 9. Propylene polymerization data for rac-Lig ¹ HfBn ₂ -a,b and rac-

Lig ¹ ZrBn ₂ -a,b at O ^º C.

[00125] Investigation of propylene polymerization behavior with rac-Og ¹ ZrBn ₂ - a,b/[Ph ₃ C] [B(C ₆ F ₅ )] at 25ºC resulted in a catalyst with a TOF of 26,000 h ^-1 and yielded isotactic polypropylene exhibiting an M _n of 174 kg/mol and MJM _n = 2.08. The iPP ([m ⁴ ] = 72%) was regioregular with stereoerrors indicating an enantiomorphic site-control enchainment mechanism. Activation with B(C ₆ Fs) ₃ and [PhNMe ₂ H][B(CoFs) ₄ ] at 25°C resulted in similar molecular weights and molecular weight distributions with activity trends reflecting those previously established. The effect of reaction temperature was investigated to find conditions for living propylene polymerization, as shown in FIG. 20. Activation of rac-Lig ¹ ZrBn ₂ -a,b with [Ph ₃ C][B(C ₆ Fs) ₄ ] at 0ºC in the presence of propylene provided a catalyst with a TOF of 183,000 h ^-1 . As before, the higher TOF at 0ºC can be attributed to the higher propylene concentration from condensed propylene in solution. Furthermore, it is unlikely that the polymerization temperature was maintained at 0ºC due to the extremely high activity of the catalyst. The polymer obtained had an M _n of 396 kg/mol and MJM _n = 2.14 with an [m ⁴ ] = 77%. Activation of ¹ with afforded a very active catalyst (TOF = 58,300 h ^-1 ) and the iPP obtained had an extremely high molecular weight (M _n = 478 kg/mol). However, the molecular weight distribution was broadened (MJM _n = 2.32) indicative of a non-living polymerization system. Interestingly, activation of rac-Lig ¹ ZrBn ₂ -a,b with B(C ₆ Fs) ₃ at 0ºC gave a catalyst (TOF = 5,300 h ^-1 ) that furnished iPP ([m ⁴ ] = 76%) with high molecular weight (M _n = 217 kg/mol) and a very narrow molecular weight distribution (MJM _n = 1.17), which indicates possible living behavior. To further demonstrate the living behavior of rac-Lig ¹ ZrBn ₂ -a,b/B(C ₆ Fs) ₃ at 0ºC, a linear increase in molecular weight versus polypropylene yield was shown, as depicted in FIG. 18 (which is a plot of M _n (•) and MJM _n (■) versus polymer yield for propylene polymerization at 0ºC catalyzed by rac-Lig ¹ ZrBn ₂ -a,b/B(C ₆ Fs) ₃ . M _n and MJM _n values were determined by gel permeation chromatography in 1,2,4-C ₆ H ₃ Cl ₃ at 140ºC (polyethylene standards)). However, as was the case for living 1-hexene polymerization with rac-Og ¹ HfBn ₂ - a,b/B(C ₆ Fs) ₃ , the obtained molecular weights were in all cases approximately four times higher than M _n theo indicating that roughly 25% of the zirconium metal centers are active in the polymerization. Monitoring the reaction of rac-Lig ¹ ZrBn ₂ -a,b with B(C ₆ Fs) ₃ in the absence of propylene by ¹⁹ F NMR spectroscopy reveals the initial formation of six main resonances (3 for each diastereomer) that progressively becomes more complex. This may suggest that catalyst decomposition competes with activation. It is also unclear if both diastereomers are active in the polymerization. Analysis of the polypropylene microstructure via ¹³ C( ¹ H) NMR spectroscopy revealed an enantiomorphic site-control enchainment mechanism (mmmr.mmrr.mrrm pentads = 2:2:1). Hence, rac-Lig ¹ ZrBn ₂ -a,b/B(C ₆ Fs) ₃ represents a new catalyst for living and isoselective propylene polymerization adding to the growing number of olefin polymerization catalysts that are capable of this behavior. It is interesting to note that in both 1-hexene and propylene polymerizations, living behavior was only observed using B(C ₆ F ₅ ) ₃ as a cocatalyst. The observed loss of living behavior when the less- coordinating [B(C ₆ F ₅ ) ₄ ]- anion is employed may be due to a dramatic increase in the rate of propagation relative to the rate of initiation for the polymerization. [00126] Example 12

[00127] Block Copolymer from Propylene and Ethylene

[00128] Despite the fact that a living polymerization system is capable of producing only one polymer chain per metal center, the real advantage lies in the ability to synthesize well-defined block copolymers yielding a near limitless number of materials. Random copolymers or physical blends of homopolymers typically give materials whose properties are in between those of each respective individual polymer. However, the mechanical properties of block copolymers are often superior to those of each respective homopolymer. This is often attributed to the ability of the different segments of some block copolymers to microphase separate into discrete domains and give rise to new morphologies. One of the most attractive block copolymer targets are those containing iPP domains due to its highly desirable mechanical properties. In addition, iPP represents the vast majority of industrially produced polypropylenes in use today, hence incorporation of these segments into block copolymers remains a highly sought after goal. To this end, a growing number of catalysts systems have been reported in the literature that are capable of furnishing block copolymers incorporating iPP segments.

[00129] Owing to the living behavior, high activity, and relatively high isoselectivity for propylene polymerization catalyzed by rac-Lig ¹ ZrBn ₂ -a,b/B(C ₆ Fs) ₃ , it was determined that it would make an ideal candidate for the synthesis of a block copolymer incorporating an iPP segment. Polymerization of propylene was initiated at 0ºC for 4 minutes to form an iPP block (M _n = 49.8 kg/mol, MJM _n = 1.17). An overpressure of ethylene was added and copolymerized with unreacted propylene in solution for 10 minutes to produce a poly(ethylene-co-propylene) block. After quenching, the resultant ϊPF-block-PEP diblock copolymer had an M _n = 122 kg/mol and MJM _n = 1.20 with an ethylene fraction (F _e ) of 33 mol%, as shown in FIG. 19. To further illustrate the formation of a diblock copolymer, an aliquot was removed from the polymerization mixture following the formation of the first block and the resultant polymers were analyzed by gel permeation chromatography. The diblock copolymer had a melting temperature (T _m ) of 114°C and a glass transition temperature (T _g ) of -55.8ºC, which is consistent with the formation of a block copolymer incorporating iPP and PEP segments.

[00130] Cyclopolymerization of 1,5-hexadiene and 1,6-heptadiene with rac-

[00131] Microstructures of cis- or trans-syndiotactic PMCP remain elusive. To date the formation of ci-issotactic PMCP has remained elusive as well. This may be due to a higher energy twist-boat conformational transition state for ring closure in the cyclization step. Modeling has suggested that more sterically encumbered ligands tend to disfavor the pseudo-chair conformation with respect to the twist-boat conformation to give rise to cis- specific ring closure. It was therefore reasoned that use of the isospecific rac-Lig ¹ ZrBn ₂ -a,b and rac-Lig ¹ HfBn ₂ -a,b catalysts bearing bulky adamantyl groups may be sterically encumbered enough to disfavor the pseudo-chair conformation and give rise to a previously unreported ci-sisotactic PMCP microstructure. Herein are reported the results for cyclopolymerization of 1,5-hexadiene and 1,6-heptadiene with rαc-Lig ¹ ZrBn ₂ -a,b and rac- Lig ¹ HfBn ₂ -a,b, an embodiment of which is depicted in FIG. 20. [00132] Methods and Materials

[00133] Example 13

[00134] Complex Syntheses

[00135] All manipulations of air- and/or water-sensitive compounds were carried out under dry nitrogen using a Braun UniLab drybox or standard Schlenk techniques. ¹³ C( ¹ H) NMR spectra of polymers were recorded using a Varian Unitylnova (600 MHz) spectrometer equipped with a 10 mm broadband probe operating at 135°C and referenced versus residual non-deuterated solvent shifts. The polymer samples were dissolved in 1,1,2,2- tetrachloroethane-d ₂ in a 5 mm O.D. tube, and spectra were collected at 135°C. For quantitative ¹³ C{ ¹ H} analysis, the polymer samples were dissolved in 1,1,2,2- tetrachloroethane-d ₂ in 10 mm O.D. tubes and the spectra were collected with inverse gated decoupling using the TYCO-25 decoupling sequence, a 30° excitation pulse width, 2.0 s acquisition time, and 10 s relaxation delay. Molecular weights (M _n and M _w ) and polydispersities (M _w /M _n ) were determined by high temperature gel permeation chromatography (GPC). Analyses were performed with a Waters Alliance GPCV 2000 GPC equipped with a Waters DRI detector and viscometer. The column set (four Waters HT 6E and one Waters HT2) was eluted with 1,2,4-trichlorobenzene containing 0.01 wt. % di-tert- butylhydroxytoluene (BHT) at 1.0 mL/min at 140ºC. Data were calibrated using monomodal polystyrene standards (from Polymer Standards Service). Polymers were usually placed in a 140ºC oven for 24 h prior to molecular weight measurements. Polymer melting points (T _m ) and glass transition temperatures (T _g ) were measured by differential scanning calorimetry (DSC) using a TA Instruments QlOOO calorimeter equipped with an automated sampler. Analyses were performed in crimped aluminum pans under nitrogen and data were collected from the second heating run at a heating rate of 10 °C/min from -100 to 200ºC, and processed with TA Q series software.

[00136] Toluene was purified over columns of alumina and copper (Q5) prior to use.

Tris(pentafluorophenyl)borane (B(C ₆ F ₅ ) ₃ ), trityl tetrakis(pentafluorophenyl)borate ([Ph ₃ C][B(C ₆ F ₅ ) ₄ ]), and N,N-dimethylanilinium tetrakis(pentafluorophenyl)borate ([PhNMe ₂ H][B(C ₆ F ₅ ) ₄ ]) were purchased from Strem and used as received. 1,5-Hexadiene was fractionally distilled and the middle fraction was dried over 4A molecular sieves for several days and then vacuum transferred and degassed using three freeze/pump/thaw cycles. The complexes rac-Lig ¹ HfBn ₂ -a,b and rac-Lig ¹ ZrBn ₂ -a,b were prepared as previously described above. [00137] Example 14

[00138] Polymer Syntheses

[00139] For 1,5-hexadiene polymerization at 25°C, in the glovebox B(C ₆ F _S ) ₃ (5.1 mg,

10 mmol) was placed into a scintillation vial along with 9 mL of toluene and 2 mL of 1,5- hexadiene. To this solution was added rac-Lig ¹ HfBn ₂ -a,b (8.5 mg, 10 mmol) dissolved in 1 mL of toluene. The polymerization was allowed to proceed for 10 minutes after which time the vial was removed from the glovebox and the polymerization was terminated by the addition of MeOH. The volatiles were removed in vacuo to furnish poly (methylene- 1,3- cyclopentane) (0.52 g, 38%). The same procedure was followed for 1,5-hexadiene polymerization using [Ph ₃ C][B(CoFs) ₄ ] and [PhNMe ₂ H][B(CoFs) ₄ ] as activators and also for the analogous rac-Lig ¹ ZrBn ₂ -a,b complex.

[00140] For 1,5-hexadiene polymerization at 0ºC, in the glovebox B(C ₆ Fs) ₃ (10.2 mg,

20 mmol) was placed into a Schlenk adapted tube along with 2 mL of toluene and 3 mL of 1,5-hexadiene. The reaction was sealed, removed from the glovebox and equilibrated in an ice bath at 0ºC for 15 minutes. To this solution was added rac-Lig ¹ HfBn ₂ -a,b (17.0 mg, 20 mmol) dissolved in 1 mL of toluene in a gas tight syringe under an active nitrogen flow. The polymerization was allowed to proceed for the desired period of time after which time the polymerization was terminated by the addition of MeOH. The volatiles were removed in vacuo to furnish poly(methylene-1,3-cyclopentane). A similar procedure was followed for 1,5-hexadiene polymerization using the analogous rac-Lig ¹ ZrBn ₂ -a,b complex. These results are shown in Table 10, with the following general conditions: 10 μmol of the complex in toluene (1 mL) was added to a 1,5-hexadiene (2 mL) solution of activator (9 mL of toluene; [Cplx]/[B] = 1.0) at 25 ºC, except for rac-Lig ¹ Hffln ₂ -a,b and rac-Ug ¹ ZrBn ₂ -a,b which were 20 μmol of the complex ([Cplx]/[B] = 1.0); 3 mL 1,5-hexadiene, 3 mL toluene. The average turnover frequency is in mol 1,5-hexadiene/(mol Cplx-h). The M _n , M _n theo, MJM _n were determined using gel permeation chromatography in 1 ,2,4-C ₆ H ₃ CI ₃ at 140ºC versus polystyrene standards. The cis % was determined by integration of the C _4,5 region of the ¹³ C( ¹ H) NMR spectrum. The enantioselectivity factor ("a") was calculated according to G.W. Coates and R.M. Waymouth, J. Am. Chem. Soc. 1993, 115, 91-98. "nd" indicates that the resonances were too broad for quantitative tacticity determination.

[00144] The tridentate phenoxyamine derivatives of zirconium and hafnium were synthesized as previously described above. The reaction of a vinyl-appended phenoxyamine ligand featuring a 1-adamantyl substituent (Lig ¹ ) with ZrBn ₄ and HfBn ₄ in toluene afforded rac-Lig ¹ ZrBn ₂ -a,b and rac-Lig ¹ HfBn ₂ -a,b as a mixture of diastereomers (55:45 ratio of a:b) in quantitative yield. [00145] Example 16

[00146] 1,5-Hexadiene Polymerization Behavior

[00147] The polymerization of 1,5-hexadiene was carried out using rac-Lig ¹ ZrBn ₂ -a,b and rac-Lig ¹ HfBn ₂ -a,b activated with boron based co-catalysts, as shown in FIG. 20. Addition of rac-Lig ¹ HfBn ₂ -a,b to a solution of [Ph ₃ C] [B(C ₆ F ₅ ) ₄ ] and 1,5-hexadiene (1:1:1685) in toluene at 25°C led to the formation of 0.73 g of PMCP (53% conversion) in 10 minutes. The reaction was quite exothermic and the solution was noted to stop stirring within 30 - 60 seconds, which may indicate some potential crosslinking. However, the obtained polymer was soluble in 1,2,4-trichlorobenzene at 135°C enabling analysis of the molecular weight by gel permeation chromatography. The polymer possessed a molecular weight (M _n ) of 322 kg/mol and a relatively narrow molecular weight distribution (Mw/M _n = 1.48). Similar molecular weights and molecular weight distributions were obtained upon activation with B(C ₆ F ₅ ) ₃ and [PhNMe ₂ H][B(C ₆ Fs) ₄ ] at 25°C, albeit with lower activity. The catalyst system rac-Lig ¹ HfBn ₂ -a,b/B(C ₆ F ₅ ) ₃ has been previously shown to be living for 1-hexene polymerization at 0ºC. A similar molecular weight distribution of the PMCP prepared using rac-Lig ¹ HfBn ₂ -a,b/B(C ₆ F ₅ ) ₃ at 25°C was obtained (MJM _n = 1.35) in comparison to that reported for 1-hexene polymerization, which prompted us to investigate the polymerization behavior of this catalyst at lower reaction temperatures. Activation of rac-Lig ¹ HfBn ₂ -a,b with B(C ₆ F ₅ ) ₃ at 0ºC in toluene resulted in the formation of 0.33 g of PMCP (16% conversion) in 10 minutes. The obtained polymer had an M _n of 211 kg/mol, however, the molecular weight distribution (MJM _n = 1.66) was too broad to indicate a living polymerization catalyst.

[00148] The 1,5-hexadiene polymerization behavior of rac-Lig ¹ ZrBn ₂ -a,b was next investigated. Activating rac-Lig ¹ ZrBn ₂ -a,b with [Ph ₃ C][B(C ₆ F ₅ ) ₄ ] in the presence of 1,5- hexadiene (1:1:1685) and toluene at 25°C led to the formation of 0.69 g of PMCP (50% conversion) in 10 minutes. Again, the reaction was noted to be very exothermic and the solution stopped stirring within 30 - 60 seconds. The polymer (M _n = 366 kg/mol) exhibited a narrow molecular weight distribution (MJM _n = 2.21) indicative of a single-site polymerization catalyst. Activation with B(C ₆ F ₅ ) ₃ and [PhNMe ₂ H][B(C ₆ F ₅ ) ₄ ] at 25°C gave rise to PMCPs with similar molecular weights and molecular weight distributions, but activity trends mirrored those of rac-Lig ¹ HfBn ₂ -a,b. None of the molecular weight distributions were sufficiently narrow to indicate any potential living behavior. However, rac-Lig ¹ ZrBn ₂ -a,b/B(C ₆ Fs) ₃ has been shown to be living for propylene polymerization at 0ºC. Thus, it was decided to screen under those same activation conditions to compare the results as obtained from the polymerization of propylene. Activation of rac-Lig ¹ ZrBn ₂ -a,b with B(C ₆ F ₅ ) ₃ at 0ºC in toluene resulted in the formation of 0.75 g of PMCP (36% conversion) in 10 minutes under rather concentrated conditions (toluene: 1, 5 -hexadiene = 1: 1 V/V). The polymer displayed an M _n of 280 kg/mol but the molecular weight distribution (MJM _n = 1.51) was again too broadened to indicate a living polymerization catalyst. While rac-Lig ¹ HfBn ₂ -a,b/B(C ₆ Fs) ₃ has been shown to be living for 1-hexene polymerization at 0ºC and living propylene polymerization is catalyzed by rac- at 0ºC ₅ neither catalyst system promotes the living polymerization of 1,5-hexadiene. [00149] Example 18

[00150] Microstructure of Poly(Methylene-1,3-Cyclopentane)

[00151] Microstructural analysis of the PMCPs was accomplished by using ¹³ C( ¹ H)

NMR spectroscopy. A typical ¹³ C{ ¹ H} NMR spectrum for PMCP produced by rac- Og ¹ HfBn ₂ -a ₅ WB(C ₆ Fs) ₃ at 0ºC is presented in FIG. 21. Resonances in the region of 30 - 45 ppm correspond to PMCP carbons as shown. Resonances were assigned with the same notation used by Coates and Waymouth (G.W. Coates, R.M. Waymouth, J. Am. Chem. Soc. 1993, 115, 91-98). The capital letters ("M" for meso, "R" for racemic) denote relative stereochemistry within the rings and lower case letters ("m" and "r") refer to the relative stereochemistry between the rings, as shown in FIG. 22. The small letter "x" denotes either m or r stereochemistry. Assignment of the cis:trans ratio can be accomplished on the basis of the relative intensities of resonances at d 32.3 and 33.5 ppm in the ¹³ C( ¹ H) NMR spectra in FIG. 23, corresponding to ring carbons C ₄ and Cs of the cis and trans repeating units respectively. For comparison, the ¹³ C( ¹ H) NMR spectrum of trans-atactic PMCP prepared with achiral Cp ₂ ZrCl ₂ /MAO is included in FIG. 23.

[00152] Many of the PMCPs produced from rac-Og ¹ ZrBn ₂ -a,b would only swell in

I,1,2,2-tetrachloroethane-d ₂ at 135°C enabling only the cis:trans ratio to be determined. The PMCPs produced from rac-Og ¹ ZrBn ₂ -a,b and rac-Og ¹ HfBn ₂ -a,b generally contained cis:trans ratios of 1.4: 1.0 to 2.9:1.0, with catalysts derived from rac-Lig ¹ HfBn ₂ -a,b showing a higher propensity towards cis-ring closure. These ratios correspond to a moderate cis- preference of σ = 0.59 - 0.74, as shown in Table 10 (in which tetrads were calculated according to Coates and Waymouth (G.W. Coates, R.M. Waymouth, J. Am. Chem. Soc. 1993, 115, 91-98), and "nd" indicates that ¹³ C( ¹ H) NMR resonances were too broad for tacticity assignment to be quantified). The tacticity of PMCP is influenced by the enantiofacial selectivity in the 1,5-hexadiene insertion step. Because both rac-Lig ¹ ZrBn ₂ -a,b and rac- Lig ¹ HfBn ₂ -a,b promote the isoselective polymerization of propylene (mmmm = 0.69 - 0.77 and 0.77 - 0.84, respectively), the polymerization of 1,5-hexadiene is expected to proceed with isotactic enantioselectivity. Due to close overlap of the ¹³ C( ¹ H) NMR resonances for the various tetrads, the experimental tetrad distribution was evaluated by deconvolution of the spectra and variation of the enatioselectivity factor (α) until an optimum fit was obtained. On ¹³ C( ¹ H) NMR analysis of soluble samples, it was possible to assign an enantiofacial selectivity of α = 0.91 to 0.96, with the 1,5-hexadiene polymerization catalyzed by rac- Lig ¹ HfBn ₂ -a,b/B(C ₆ Fs) ₃ at 0ºC displaying the highest cis-preference (σ = 0.74) with an isospecificity factor of α = 0.95. This enantiofacial selectivity correlates well to polymerization of propylene under the same conditions (mmmm = 0.84, α = 0.97). [00153] As can be concluded from the results depicted in Table 11, the PMCP synthesized from complexes rac-Lig ¹ ZrBn ₂ -a,b and rac-Lig ¹ HfBn ₂ -a,b contain a high proportion of MmM resonances and represent a new, previously unreported microstructure with a predominance ofcis-isotactic rings. ¹³ C( ¹ H) NMR resonances representing RmR and MrM tetrads were not observed. While PMCPs have been synthesized with a high degree of cis-cyclopentane rings, a total lack of enantiofacial selectivity was observed. Furthermore, PMCPs have been reported with a high selectivity for isotactic enchainment, however, they all contain a predominance of trans-cyclopentane rings. Thus, this work represents the first report of a relatively highly maximum ordered cis- cisiostactic microstructure for PMCP.

[00155] Example 19

[00156] 1,6-Heptadiene Polymerization Behavior

[00157] Owing to the relatively highcis-isotactic content of the PMCP produced by rac-Lig ¹ HfBn ₂ -a,b/B(C ₆ F ₅ ) ₃ at OºC (σ = 0.74, α = 0.95), this system was investigated for the cyclopolymerization of 1,6-heptadiene. It has been shown that an increase in the diene length results in an increase in the cis ring content of the cyclopolymers. Cyclopolymerization of 1,6-heptadiene with rac-Lig ¹ HfBn ₂ -a,b/B(C ₆ F ₅ ) ₃ at 0ºC in toluene resulted in the formation of O.llg (15% conversion) of poly(methylene-1,3-cyclohexane) ("PMCH") in 20 minutes. The PMCH had an M _n of 87 kg mol ^-1 and MJM _n = 1.38. Inspection of the thermal properties of the PMCH revealed a glass transition temperature (T _g ) of 103.1ºC and no melting transition up to 380ºC. Analysis of the PMCH microstructure by ¹³ C{ ¹ H} NMR spectroscopy revealed the presence of only 5 resonances that correspond to >97% cis ring content, as shown in FIG. 21. This is the first synthesis of a nearly perfect cis-isotactic microstructure for PMCH.

[00158] The present study set out to explore the 1,5-hexadiene cyclopolymerization behavior for catalysts derived from rac-Lig ¹ HfBn ₂ -a,b and rac-Lig ¹ ZrBn ₂ -a,b. Upon activation, these complexes formed highly active cyclopolymerization catalysts for 1,5- hexadiene furnishing PMCP with a predominance of cis-cyclopentane rings (cis:trans ratio = 1.4:1.0 to 2.9: 1.0). Catalysts derived from rac-Lig ¹ HfBn ₂ -a,b showed a higher propensity towards cis-ring closure than those derived from rac-Lig ¹ ZrBn ₂ -a,b. Furthermore, it was demonstrated that the enantiofacial selectivity for the insertion step of 1,5-hexadiene polymerization proceeded with a relative high selectivity for isotactic enchainment. The obtained PMCPs represent the first report of a highly cis-isotactic microstructure. Cyclopolymerization of 1,6-heptadiene with rac-Lig ¹ HfBn ₂ -a,b/B(C ₆ F ₅ ) ₃ produced PMCH with a nearly perfect -cisiostactic microstructure.

[00159] Unless otherwise defined herein, scientific and technical terminologies employed in the present disclosure shall have the meanings that are commonly understood and used by one of ordinary skill in the art. Further, unless otherwise required by context, it will be understood that singular terms shall include plural forms of the same and plural terms shall include the singular. In particular, the singular forms "a" and "an" include the plural unless the context clearly indicates otherwise.

[00160] Unless otherwise expressly specified, all of the numerical ranges, amounts, values and percentages such as those for quantities of materials, durations of times, temperatures, operating conditions, ratios of amounts, and the like shall be understood as modified in all instances by the term "about." As a result, unless there is indication to the contrary, the numerical parameters set forth in the present disclosure and attached claims are approximations that can vary as desired. [00161] Although the present invention has been described in connection with a preferred embodiment, it should be understood that modifications, alterations, and additions can be made to the invention without departing from the scope of the invention as defined by the claims.