A series of novel half-titanocene complexes CpTiCl 2[S-2-R-6-(PPh 2)C 6H 3] (Cp = C 5H 5, 2a, R = H; 2b, R = Ph; 2c, R = SiMe 3) have been synthesized by treating CpTiCl 3 with the sodium of the ligands, 2-R-6-(PPh 2)C 6H 3SNa, which were prepared by the corresponding ligands and NaH. These complexes have been characterized by 1H, 13C and 31P NMR as well as elemental analyses. Structures for 2 a–b were further confirmed by X-ray crystallography. Complexes 2 a–b adopt five-coordinate, distorted square-pyramid geometry around the titanium center, in which the equatorial positions are occupied by sulfur and phosphorus atoms of the chelating phosphine-thiophenolate and two chlorine atoms, and the cyclopentadienyl ring is coordinated on the axial position. The complexes 2a –c were investigated as the catalysts for ethylene polymerization and copolymerization of ethylene with norbornene in the presence of MMAO or Ph 3CB(C 6F 5) 4/ iBu 3Al as the cocatalyst. All complexes exhibited low to moderate activities towards homopolymerization of ethylene. However, they displayed moderate to high activities towards copolymerization of ethylene with norbornene.
References
[1]
Nomura, K.; Liu, J.Y.; Padmanabhan, S.; Kitiyanan, B. Nonbridged half-metallocenes containing anionic ancillary donor ligands: New promising candidates as catalysts for precise olefin polymerization. J. Mol. Catal. A 2007, 267, 1–29, doi:10.1016/j.molcata.2006.11.006.
[2]
Nomura, K. Half-titanocenes containing anionic ancillary donor ligands as promising new catalysts for precise olefin polymerisation. Dalton Trans. 2009, 38, 8811–8823, doi:10.1039/b910407k.
[3]
Redshaw, C.; Tang, Y. Tridentate ligands and beyond in group IV metal α-olefin homo-/co-polymerization catalysis. Chem. Soc. Rev. 2012, 41, 4484–4510, doi:10.1039/c2cs35028a.
Sinn, H.; Kaminsky, W. Ziegler-Natta Catalysis. Adv. Organomet. Chem. 1980, 18, 99–149.
[10]
Stephan, D.W.; Stewart, J.C.; Guerin, F.; Spence, R.E.; Xu, W.; Harrison, D.G. Phosphinimides as a Steric Equivalent to Cyclopentadienyl:？ An Approach to Ethylene Polymerization Catalyst Design. Organometallics 1999, 18, 1116–1118.
[11]
Nomura, K.; Naga, N.; Miki, M.; Yanagi, K.; Imai, A. Synthesis of Various Nonbridged Titanium(IV) Cyclopentadienyl-Aryloxy Complexes of the Type CpTi(OAr)X2 and Their Use in the Catalysis of Alkene Polymerization. Important Roles of Substituents on both Aryloxy and Cyclopentadienyl Groups. Organometallics 1998, 17, 2152–2154, doi:10.1021/om980106r.
[12]
Mahanthappa, M.K.; Cole, A.P.; Waymouth, R.M. Synthesis, Structure, and Ethylene/α-Olefin Polymerization Behavior of (Cyclopentadienyl)(nitroxide)titanium Complexes. Organometallics 2004, 23, 836–845, doi:10.1021/om034096s.
[13]
Anti？olo, A.; Carrillo-Hermosilla, F.; Corrochano, A.; Fernández-Baeza, J.; Lara-Sanchez, A.; Ribeiro, M.R.; Lanfranchi, M.; Otero, A.; Pellinghelli, M.A.; Portela, M.F.; et al. Synthesis of Zirconium(IV) Monocyclopentadienyl？Aryloxy Complexes and Their Use in Catalytic Ethylene Polymerization. X-ray Structure of (η5-C5Me5)Zr{2,6-OC6H3(CH3)2}3. Organometallics 2000, 19, 2837–2843, doi:10.1021/om000209l.
[14]
Tamm, M.; Randoll, S.; Herdtweck, E.; Kleigrewe, N.; Kehr, G.; Erker, G.; Rieger, B. Imidazolin-2-iminato titanium complexes: Synthesis, structure and use in ethylene polymerization catalysis. Dalton Trans. 2006, 459–467.
[15]
Shah, S.A.A.; Dorn, H.; Voigt, A.; Roesky, H.W.; Parisini, E.; Schmidt, H.G.; Noltemeyer, M. Group 4 Metal Amido Fluorides and Chlorides:？ Molecular Structures and the First Comparison in Ethylene Polymerization Catalysis. Organometallics 1996, 15, 3176–3181, doi:10.1021/om960177v.
[16]
Sinnema, P.J.; Spaniol, T.P.; Okuda, J. Non-bridged amido cyclopentadienyl complexes of titanium: synthesis, characterization, and olefin polymerization catalysis. J. Organomet. Chem. 2000, 598, 179–181, doi:10.1016/S0022-328X(99)00701-9.
[17]
Kretschmer, W.P.; Dijkhuis, C.; Meetsma, A.; Hessen, B.; Teuben, J.H. A highly efficient titanium-based olefin polymerisation catalyst with a monoanionic iminoimidazolidide π-donor ancillary ligand. Chem. Commun. 2002, 608–609.
[18]
Zhang, S.B.; Piers, W.E.; Gao, X.L.; Parvez, M. The Mechanism of Methane Elimination in B(C6F5)3-Initiated Monocyclopentadienyl-Ketimide Titanium and Related Olefin Polymerization Catalysts. J. Am. Chem. Soc. 2000, 122, 5499–5509.
[19]
Zhang, W.; Sita, L.R. Highly Efficient, Living Coordinative Chain-Transfer Polymerization of Propene with ZnEt2:？ Practical Production of Ultrahigh to Very Low Molecular Weight Amorphous Atactic Polypropenes of Extremely Narrow Polydispersity. J. Am. Chem. Soc. 2008, 130, 442–443, doi:10.1021/ja078120v.
[20]
Vollmerhaus, R.; Shao, P.; Taylor, N.J.; Collins, S. Synthesis of and Ethylene Polymerization Using Iminophosphonamide Complexes of Group 4. Organometallics 1999, 18, 2731–2733, doi:10.1021/om990341p.
Liu, S.F.; Sun, W.H.; Zeng, Y.N.; Wang, D.; Zhang, W.J.; Li, Y. Syntheses, Characterization, and Ethylene (Co-)Polymerization Screening of Amidate Half-Titanocene Dichlorides. Organometallics 2010, 29, 2459–2464, doi:10.1021/om1000748.
[23]
Bott, R.K.J.; Hughes, D.L.; Schormann, M.; Bochmann, M.; Lancaster, S.J. Monocyclopentadienyl phenoxy-imine and phenoxy-amine complexes of titanium and zirconium and their application as catalysts for 1-alkene polymerisation. J. Organomet. Chem. 2003, 665, 135–149.
[24]
Liu, S.R.; Li, B.X.; Liu, J.Y.; Li, Y.S. Synthesis, Structure and Ethylene (Co)Polymerization Behavior of New Nonbridged Half-metallocene-type Titanium Complexes Based on Bidentate β-Enaminoketonato Ligands. Polymer 2010, 51, 1921–1925.
[25]
Qi, C.H.; Zhang, S.B.; Sun, J.H. Synthesis, structure and ethylene polymerization behavior of titanium phosphinoamide complexes. J. Organomet. Chem. 2005, 690, 2941–2946, doi:10.1016/j.jorganchem.2005.03.016.
Zhang, J.; Lin, Y.J.; Jin, G.X. Synthesis, Characterization, and Ethylene Polymerization of Group IV Metal Complexes with Mono-Cp and Tridentate Aryloxide or Arylsulfide Ligands. Organometallics 2007, 26, 4042–4047, doi:10.1021/om700338y.
[28]
Tang, X.Y.; Wang, Y.X.; Li, B.X.; Liu, J.Y.; Li, Y.S. Highly Efficient Ethylene/Norbornene Copolymerization by O-Di(phenyl)phosphanylphenolate-Based Half-Titanocene Complexes. J. Polym. Sci. Part A 2013, 51, 1585–1594, doi:10.1002/pola.26528.
[29]
Stephan, D.W.; Stewart, J.C.; Guerin, F.; Courtenay, S.; Kickham, J.; Hollink, E.; Beddie, C.; Hoskin, A.; Graham, T.; Wei, P.R.; et al. An Approach to Catalyst Design: Cyclopentadienyl-Titanium Phosphinimide Complexes in Ethylene Polymerization. Organometallics 2003, 22, 1937–1947, doi:10.1021/om020954t.
[30]
Nomura, K.; Tsubota, M.; Fujiki, M. Efficient Ethylene/Norbornene Copolymerization by (Aryloxo)(indenyl)titanium(IV) Complexes-MAO Catalyst System. Macromolecules 2003, 36, 3797–3799, doi:10.1021/ma034215f.
[31]
Nomura, K.; Fujki, K. Effect of Cyclopentadienyl and Amide Fragment in Olefin Polymerization by Nonbridged (Amide)(cyclopentadienyl)titanium(IV) Complexes of the Type Cp’TiCl2[N(R1)R2]-Methylaluminoxane (MAO) Catalyst Systems. Macromolecules 2003, 36, 2633–2641, doi:10.1021/ma030053b.
[32]
Wang, W.; Tanaka, T.; Tsubota, M.; Fujiki, M.; Yamanaka, S.; Nomura, K. Effect of Cyclopentadienyl Fragment in Copolymerization of Ethylene with Cyclic Olefins Catalyzed by Non-Bridged (Aryloxo)(cyclopentadienyl)titanium(IV) Complexes. Adv. Synth. Catal. 2005, 347, 433–446, doi:10.1002/adsc.200404275.
[33]
Keaton, R.J.; Jayaratne, K.C.; Henningsen, D.A.; Koterwas, L.A.; Sita, L.R. Dramatic Enhancement of Activities for Living Ziegler-Natta Polymerizations Mediated by Exposed” Zirconium Acetamidinate Initiators:？ The Isospecific Living Polymerization of Vinylcyclohexane. J. Am. Chem. Soc. 2001, 123, 6197–6198.
[34]
Jayaratne, K.C.; Keaton, R.J.; Henningsen, D.A.; Sita, L.R. Living Ziegler？Natta Cyclopolymerization of Nonconjugated Dienes:？ New Classes of Microphase-Separated Polyolefin Block Copolymers via a Tandem Polymerization/Cyclopolymerization Strategy. J. Am. Chem. Soc. 2000, 122, 10490–10491, doi:10.1021/ja002558c.
[35]
Jayaratne, K.C.; Sita, L.R. Stereospecific Living Ziegler？Natta Polymerization of 1-Hexene. J. Am. Chem. Soc. 2000, 122, 958–959, doi:10.1021/ja993808w.
[36]
Zhang, W.; Sita, L.R. Investigation of Dynamic Intra- and Intermolecular Processes within a Tether-Length Dependent Series of Group 4 Bimetallic Initiators for Stereomodulated Degenerative Transfer Living Ziegler–Natta Propene Polymerization. Adv. Synth. Catal. 2008, 350, 439–447, doi:10.1002/adsc.200700506.
[37]
Doherty, S.; Errington, R.J.; Jarvis, A.P.; Collins, S.; Clegg, W.; Elsegood, M.R.J. Polymerization of Ethylene by the Electrophilic Mixed Cyclopentadienylpyridylalkoxide Complexes [CpM{NC5H4(CR2O)-2}Cl2] (M = Ti, Zr, R = Ph, Pri). Organometallics 1998, 17, 3408–3410, doi:10.1021/om980222u.
[38]
Dove, A.P.; Xie, X.; Waymouth, R.M. Cyclopentadienyl titanium hydroxylaminato complexes as highly active catalysts for the polymerization of propylene. Chem. Commun. 2005, 16, 2152–2154, doi:10.1039/b418778d.
[39]
Liu, J.Y.; Liu, S.R.; Li, B.X.; Li, Y.G.; Li, Y.S. Synthesis and Characterization of Novel Half-Metallocene-Type Group IV Complexes Containing Phosphine Oxide-Phenolate Chelating Ligands and Their Application to Ethylene Polymerization. Organometallics 2011, 30, 4052–4059, doi:10.1021/om200317x.
[40]
Hu, P.; Lin, Y.J.; Jin, G.X. Syntheses, Characterization, and Ethylene Polymerization of Half-Sandwich Zirconium Complexes with Tridentate Imino-Quinolinol Ligands. Organometallics 2011, 30, 1008–1012, doi:10.1021/om101059v.
[41]
Long, R.J.; Gibson, V.C.; White, A.J.P.; Williams, D.J. Combining Hard and Soft Donors in Early-Transition-Metal Olefin Polymerization Catalysts. Inorg. Chem. 2006, 45, 511–513, doi:10.1021/ic0517927.
[42]
Long, R.J.; Gibson, V.C.; White, A.J.P. Group 4 Metal Olefin Polymerization Catalysts Stabilized by Bidentate O,P Ligands. Organometallics 2008, 27, 235–245.
[43]
He, L.P.; Liu, J.Y.; Li, Y.G.; Liu, S.R.; Li, Y.S. High-Temperature Living Copolymerization of Ethylene with Norbornene by Titanium Complexes Bearing Bidentate [O, P] Ligands. Macromolecules 2009, 42, 8566–8570, doi:10.1021/ma901285a.
Yoshida, Y.; Saito, J.; Mitani, M.; Takagi, Y.; Matsui, S.; Ishii, S.; Nakano, T.; Kashiwa, N.; Fujita, T. Living ethylene/norbornene copolymerisation catalyzed by titanium complexes having two pyrrolide-imine chelate ligands. Chem. Commun. 2002, 1298–1299.
[46]
Ruchatz, D.; Fink, G. Ethene-Norbornene Copolymerization Using Homogenous Metallocene and Half-Sandwich Catalysts:？ Kinetics and Relationships between Catalyst Structure and Polymer Structure. 1. Kinetics of the Ethene-Norbornene Copolymerization Using the [(Isopropylidene)(η5-inden-1-ylidene-η5-cyclopentadienyl)]zirconium Dichloride/Methylaluminoxane Catalyst. Macromolecules 1998, 31, 4669–4673, doi:10.1021/ma971041r.
[47]
Provasoli, A.; Ferro, D.R.; Tritto, I.; Boggioni, L. The Conformational Characteristics of Ethylene-Norbornene Copolymers and Their Influence on the 13C NMR Spectra. Macromolecules 1999, 32, 6697–6706, doi:10.1021/ma990739x.
[48]
Hasan, T.; Ikeda, T.; Shiono, T. Ethene-Norbornene Copolymer with High Norbornene Content Produced by ansa-Fluorenylamidodimethyltitanium Complex Using a Suitable Activator. Macromolecules 2004, 37, 8503–8509, doi:10.1021/ma048492d.
[49]
Li, X.F.; Dai, K.; Ye, W.P.; Pan, L.; Li, Y.S. New Titanium Complexes with Two β-Enaminoketonato Chelate Ligands:？ Syntheses, Structures, and Olefin Polymerization Activities. Organometallics 2004, 23, 1223–1230, doi:10.1021/om030396y.
[50]
Yoshida, Y.; Mohri, J.; Ishii, S.; Mitani, M.; Saito, J.; Matsui, S.; Makio, H.; Nakano, T.; Tanaka, H.; Onda, M.; et al. Living Copolymerization of Ethylene with Norbornene Catalyzed by Bis(Pyrrolide？Imine) Titanium Complexes with MAO. J. Am. Chem. Soc. 2004, 126, 12023–12032, doi:10.1021/ja048357g.
[51]
Ruchatz, D.; Fink, G. Ethene-Norbornene Copolymerization Using Homogenous Metallocene and Half-Sandwich Catalysts:？ Kinetics and Relationships between Catalyst Structure and Polymer Structure. 2. Comparative Study of Different Metallocene- and Half-Sandwich/Methylaluminoxane Catalysts and Analysis of the Copolymers by 13C Nuclear Magnetic Resonance Spectroscopy. Macromolecules 1998, 31, 4674–4680, doi:10.1021/ma971042j.
[52]
Ruchatz, D.; Fink, G. Ethene-Norbornene Copolymerization with Homogeneous Metallocene and Half-Sandwich Catalysts:？ Kinetics and Relationships between Catalyst Structure and Polymer Structure. 3. Copolymerization Parameters and Copolymerization Diagrams. Macromolecules 1998, 31, 4681–4683, doi:10.1021/ma971043b.
[53]
Ruchatz, D.; Fink, G. Ethene-Norbornene Copolymerization with Homogeneous Metallocene and Half-Sandwich Catalysts:？ Kinetics and Relationships between Catalyst Structure and Polymer Structure. 4. Development of Molecular Weights. Macromolecules 1998, 31, 4684–4686, doi:10.1021/ma9710444.
[54]
Tritto, I.; Marestin, C.; Boggioni, L.; Zetta, L.; Provasoli, A.; Ferro, D.R. Ethylene-Norbornene Copolymer Microstructure. Assessment and Advances Based on Assignments of 13C NMR Spectra. Macromolecules 2000, 33, 8931–8944.
