Diamido Complexes of Titanium and Zirconium as Catalyst Precursors for Ethylene Polymerization

Document Type : Research Article


1 Department of Chemistry, Mirpur University of Science and Technology (MUST), Mirpur 10250, (AJK) PAKISTAN

2 Laboratorium für Anorganische Chemie, Universität Bayreuth, Postfach 101251, D-95440 Bayreuth, GERMANY


A series of 8 new complexes of titanium and zirconium with diamido ligands bearing an ethylene and propylene bridge between the two amido groups were synthesized and tested for ethylene polymerization. Titanium complexes bearing an ethylene bridge between the two amido groups showed higher activities than the derivatives with a propylene bridge. In the case of the zirconium complexes, the propylene bridged complexes were more active than the corresponding ethylene bridged. The introduction of bulky groups on the ligand structure resulted in an increase in the activity. DFT calculations were performed to determine the activation energy barriers for different reaction steps. The calculated activation energy for the insertion of ethylene into an M-CH3 bond is in the range of 12.2-16.8 kcal/mol and the activation energy for the chain termination via β-H transfer reaction is 12.5-14.4 kcal/mol.


Main Subjects

 [4] Pinheiro A. C., da Silva S. M., Roisnel T., Kirillov E., Carpentier J.-F., Casagrande Jr. O. L., Synthesis and Structural Characterization of Zirconium Complexes Supported by Tridentate Pyrrolide-Imino Ligands with Pendant N-, O- and S-donor Groups and Their Application in Ethylene Polymerization, New J. Chem., 42(2): 1477-1483 (2018).
[5] Baier M.C., Zuideveld M.A., Mecking S., Post-Metallocenes in the Industrial Production of Polyolefins, Angew. Chem. Int. Ed., 53(37): 9722-9744 (2014).
[6] Rishina L.А., Kissin Y.V., Lalayan S.S., Ch. Gagieva S., Тuskaev V.А., Krasheninnikov V.G., Polymerization of Alkenes with a Post‐Metallocene Catalyst Containing a Titanium Complex with an Oxyquinolinyl Ligand, J. Polym. Sci. Part A: Polym. Chem., 55(11): 1844-1854 (2017).
[7] Matsugi T., Fujita T., High-Performance Olefin Polymerization Catalysts Discovered on the Basis of a New Catalyst Design Concept, Chem. Soc. Rev., 37(6): 1264-1277 (2008).
[9] Nomura K., Zhang S., Design of Vanadium Complex Catalysts for Precise Plefin Polymerization, Chem. Rev.,111(3): 2342-2362 (2011).
[10] Wu J.-Q., Li Y.-S., Well-Defined Vanadium Complexes as the Catalysts for Olefin Polymerization, Coord. Chem. Rev., 255: 2303-2314 (2011).
[11] Gibson V. C., Redshaw C., Solan G. A., Bis(imino)pyridines: Surprisingly Reactive Ligands and a Gateway to New Families of Catalysts, Chem. Rev., 107(5): 1745-1776 (2007).
[12] Gibson V. C., Spitzmesser S. K., Advances in Non-Metallocene Olefin Polymerization Catalysis, Chem. Rev.,103(1): 283-316 (2003).
[13] Ittel S. D., Johnson L. K., Brookhart M., Late-Metal Catalysts for Ethylene Homo- and Copolymerization, Chem. Rev.,100(4): 1169-1204 (2000).
[14] Sun W.-H., Yang H., Li Z., Li Y., Vinyl Polymerization of Norbornene with Neutral Salicylaldiminato Nickel(II) Complexes, Organometallics, 22(18): 3678-3683 (2003).
[15] Mitani M., Furuyama R., Mohri J., Saito J., Ishii S., Terao H., Kashiwa N., Fujita T., Fluorine- and Trimethylsilyl-Containing Phenoxy-Imine Ti Complex for Highly Syndiotactic Living Polypropylenes with Extremely High Melting Temperatures, J. Am. Chem. Soc.,124(27): 7888-7889 (2002).
[16] Reza H.M., Shadi H., Ashkan F., The Effect of Structural Parameters on the Cross-Linking of Various Grades of LLDPE, Iran. J. Chem. Chem. Eng. (IJCCE), 37(1): 175-183 (2018).
[17] Small B. L., Brookhart M., Bennet A. M. A., Highly Active Iron and Cobalt Catalysts for the Polymerization of Ethylene, J. Am. Chem. Soc., 120(16): 4049-4050 (1998).
[18] Britovsek G.J.P., Gibson V.C., Kimberley B.S., Maddox P.J., McTavish S.J., Solan G.A., White A.J.P., Williams D. J., Novel Olefin Polymerization Catalysts Based on Iron and Cobalt, Chem. Commun., 0(7): 849-850 (1998).
[20] Johnson L.K., Killian C.M., Brookhart M., New Pd(II)- and Ni(II)-Based Catalysts for Polymerization of Ethylene and .Alpha.-Olefins, J. Am. Chem. Soc., 117(23): 6414-6415 (1995).
[21] Johnson L.K., Mecking S., Brookhart M., Copolymerization of Ethylene and Propylene with Functionalized Vinyl Monomers by Palladium(II) Catalysts, J. Am. Chem. Soc., 118(1): 267-268 (1996).
[22] Mecking S., Johnson L.K., Wang L., Brookhart M., Mechanistic Studies of the Palladium-Catalyzed Copolymerization of Ethylene and α-Olefins with Methyl Acrylate, J. Am. Chem. Soc., 120(5): 888-899 (1998).
[23] Killian C.M., Tempel D.J., Johnson L.K., Brookhart M., Living Polymerization of α-Olefins Using NiII−α-Diimine Catalysts. Synthesis of New Block Polymers Based on α-Olefins, J. Am. Chem. Soc., 118(46): 11664-11665 (1996).
[24] Feldman J., McLain S. J., Parthasarathy A., Marshall W.J., Calabrese J.C., Arthur S.D., Electrophilic Metal Precursors and a β-Diimine Ligand for Nickel(II)- and Palladium(II)-Catalyzed Ethylene Polymerization, Organometallics, 16(8): 1514-1516 (1997).
[26] Brown L. A., Anderson Jr. W.C., Mitchell N.E., Gmernicki K.R., Long B.K., High Temperature, Living Polymerization of Ethylene by a Sterically-Demanding Nickel(II) α-Diimine Catalyst, Polymers, 10(1): 41-49 (2018).
[27] Azoulay J. D., Rojas R.S., Serrano A.V., Ohtaki H., Galland G.B., Wu G., Bazan G.C., Nickel α‐Keto‐β‐Diimine Initiators for Olefin Polymerization, Angew. Chem. Int. Ed., 48(6): 1089-1092 (2009).
[28] Sokolohorskyj A., Železník O., Císařová I., Lenz J., Lederer A., Merna J., α‐keto‐β‐diimine Nickel‐Catalyzed Olefin Polymerization: Effect of Ortho‐Aryl Substituents and Preparation of Stereoblock Copolymers, J. Polym. Sci. Part A: Polym. Chem., 55(15): 2440-2449 (2017).
[29] Matsui S., Tohi Y., Mitani M., Saito J., Makio H., Tanaka H., Nitabaru M., Nakano T., Fujita T., New Bis(salicylaldiminato) Titanium Complexes for Ethylene Polymerization, Chem. Lett., 28(10): 1065-1066 (1999).
[30] Matsui S., Mitani M., Saito J., Matsukawa N., Tanaka H., Nakano T., Fujita T.,  Post-Metallocenes: Catalytic Perfomance of New Bis(salicylaldiminato) Zirconium Complexes for Ethylene Polymerization, Chem. Lett., 29(5): 554-555 (2000).
[32] Matsui S., Mitani M., Saito J., Tohi Y., Makio H., Matsukawa N., Takagi Y., Tsuru K., Nitabaru M., Nakano T., Tanaka H., Kashiwa N., Fujita T., A Family of Zirconium Complexes Having Two Phenoxy-Imine Chelate Ligands for Olefin Polymerization, J. Am. Chem. Soc., 123(8): 6847-6856 (2001).
[33] Carone C. L. P., Fim F. C., Bisatto R., Jahno V. D., Lemos C., Basso N. R. S., Einloft S., Galland G. B., Ethylene Polymerization Catalyzed by Diamide Complexes of Ti(IV) and Zr(IV), J. Appl. Polym. Sci., 110(1): 270-275 (2008).
[34] Scollard D.J., McConville D.H., Payne N.C., Vittal J.J., Polymerization of α-Olefins by Chelating Diamide Complexes of Titanium, Macromolecules, 29(15): 5241-5243 (1996).
[35] Scollard D.J., McConville D.H., Living Polymerization of α-Olefins by Chelating Diamide Complexes of Titanium, J. Am. Chem. Soc., 118(41): 10008-10009 (1996).
[36] Lee C. H., La Y.-H., Park S. J., Park J. W., Preparation of N,N´-Disilylated 1,8-Diaminonaphthalene Chelates and Their Group 4 Metal Complexes for Ethylene Polymerization,Organometallics, 17(17): 3648-3655 (1998).
[37] Warren T.H., Schrock R.R., Davis W.M., Synthesis of Group 4 Organometallic Complexes That Contain the Bis(borylamide) Ligand [Mes2BNCH2CH2NBMes2]2-, Organometallics, 15(2): 562-569 (1996).
[38] Horton A. D., de With J., van der Linden A. J., van de Weg H., Cationic Alkylzirconium Complexes Based on a Tridentate Diamide Ligand: New Alkene Polymerization Catalysts, Organometallics, 15(12): 2672-2674 (1996).
[39] Scollard J. D., McConville D. H., Vittal J. J., Bulky Chelating Diamide Complexes of Zirconium: Synthesis, Structure, and Reactivity of d0 Alkyl Derivatives, Organometallics, 16(20): 4415-4420 (1997).
[40] Scollard J.D., McConville D.H., Vittal J.J., Payne N.C., Chelating Diamide Complexes of Titanium: New Catalyst Precursors for the Highly Active and Living Polymerization of α-Olefins, J. Mol. Catal., 128: 201-214 (1998).
[41] Uozumi T., Tsubaki S., Jin J. Z., Sano T., Soga K., Isospecific Propylene Polymerization Using the [ArN(CH2)3NAr]TiCl2/Al(iBu)3/Ph3CB(C6F5)4 Catalyst System in the Presence of Cyclohexene, Macromol. Chem. Phys., 202(17): 3279-3283 (2001).
[42] Tsubaki S., Jin J., Ahn C. H., Sano T., Uozumi T., Soga K., Synthesis of Isotactic Poly(propylene) by Titanium Based Catalysts Containing Diamide Ligands, Macromol. Chem. Phys., 202(4): 482-487 (2001).
[43] Ahn C. H., Tahara M., Uozumi T., Jin J., Tsubaki S., Sano T., Soga K., Copolymerization of 2‐butene  and Ethylene with Catalysts Based on Ttanium and Zirconium Complexes, Macromol. Rapid Commun., 21(7): 385-389 (2000).
[44] Frisch M.J., Trucks G.W., Schlegel H.B., Scuseria G.E., Robb M.A., Cheeseman J.R., Scalmani G., Barone V., Petersson G.A., Nakatsuji H., Li X., Caricato M., Marenich A., Bloino J., Janesko B.G., Gomperts R., Mennucci B., Hratchian H.P., Ortiz J.V., Izmaylov A.F., Sonnenberg J.L., Williams-Young D., Ding F., Lipparini F., Egidi F., Goings J., Peng B., Petrone A., Henderson T., Ranasinghe D., Zakrzewski V.G., Gao J., Rega N., Zheng G., Liang W., Hada M., Ehara M., Toyota K., Fukuda R., Hasegawa J., Ishida M., Nakajima T., Honda Y., Kitao O., Nakai H., Vreven T., Throssell K., Montgomery J.A., Jr., Peralta, F. Ogliaro, M. Bearpark, J. J. Heyd, E. Brothers J. E., Kudin K.N., Staroverov V.N., Keith T., Kobayashi R., Normand J., Raghavachari K., Rendell A., Burant J.C., Iyengar S.S., Tomasi J., Cossi M., Millam J.M., Klene M., Adamo C., Cammi R., Ochterski J.W., Martin R.L., Morokuma K., Farkas O., Foresman J.B., Fox D.J., Gaussian 09, Revision D.01, Gaussian, Inc. Wallingford CT (2009).
[45] Becke A. D., Density‐Functional Thermochemistry. III. The Role of Exact Exchange, J. Chem. Phys., 98(7): 5648-5652 (1993).
[46] Lee C., Yang W., Parr R. G., Development of the Colic-Salvetti Correlation-Energy Formula Into a Functional of the Electron Density, Phys. Rev. B, 37(2): 785-789 (1988).
[47] Stephens P.J., Devlin F.J., Chabalowski C.F., Frisch M.J., Ab Initio Calculation of Vibrational Absorption and Circular Dichroism Spectra Using Density Functional Force Fields, J. Phys. Chem., 98(45): 11623-11627 (1994).
[48] Schlegel H.B., Optimization of Equilibrium Geometries and Transition Structures, J. Comput. Chem., 3(2): 214-218 (1982).
[49] Rappe A. T., Skiff W. M., Casewit C. J., Modeling Metal-Catalyzed Olefin Polymerization, Chem. Rev., 100(4): 1435-1456 (2000).
[50] Zhang C.-G., Zhang L., Li H., Yu S.-Y., Wang Z.-X., Differences between Insertions of Ethylene into Metallocene and Non-Metallocene Ethylene Polymerization Catalysts, J. Phys. Org. Chem., 26(1): 70-76 (2013).
[51] Castonguay L.A., Rappe A.K., Ziegler-Natta Catalysis. A Theoretical Study of the Isotactic Polymerization of Propylene, J. Am. Chem. Soc., 114(14): 5832-5842 (1992).
[52] Exposito M. T., Martinez S., Ramos J., Cruz V., Lopez A., Munoz-Escalona A., Haider N., Martinez-Salazar J., Ethylene/Styrene Copolymerisation by Homogeneous Metallocene Catalysts: Experimental and Molecular Simulations Using Rac-Ethylenebis(tetrahydroindenyl) MCl2 [M=Ti,Zr] Systems, Polymer, 45(26): 9029-9038 (2004).
[55] Laine A., Linnolahti M., Pakkanen T. A., Severn J. R., Kokko E., Pakkanen A., Elemental Reactions in Copolymerization of α-Olefins by Bis(cyclopentadienyl) Zirconocene and Hafnocene: Effects of the Metal as a Function of the Monomer and the Chain End, Organometallics, 30(6): 1350-1358 (2011).
[57] Lohrenz J. C. W., Woo T. K., Ziegler T., A Density Functional Study on the Origin of the Propagation Barrier in the Homogeneous Ethylene Polymerization with Kaminsky-Type Catalysts,J. Am. Chem. Soc., 117(51): 2793-12800 (1995).