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Published July 1, 2011 | public
Journal Article

Bis-ligated Ti and Zr complexes of chelating N-heterocyclic carbenes


In this communication we report the synthesis of novel titanium and zirconium complexes ligated by bidentate "salicylaldimine-like" N-heterocyclic carbenes (NHC). Double addition of the NHC chelate to either TiCl_4(thf)_2 or ZrCl_4 forms bis-ligated organometallic fragments with a distorted octahedral geometry. These complexes are rare examples of group IV transition-metal NHC adducts. Preliminary catalytic tests demonstrate that in the presence of methylaluminoxane (MAO) these complexes are useful initiators for the polymerization of ethylene and the copolymerization of ethylene with norbornene and 1-octene.

Additional Information

© 2011 Elsevier B.V. Received 4 March 2011. Received in revised form 20 March 2011. Accepted 23 March 2011. This publication was based on work supported by Award No. K-C1-019-12 made by King Abdullah University of Science and Technology (KAUST). The support of King Fahd University of Petroleum and Minerals (KFUPM) is also highly appreciated. We would like to thank Dr. Vincent Lavallo (Caltech) for helpful discussion and technical support, Larry Henling and Mike Day (Caltech) for X-ray crystallographic analysis, Lester McIntosh (Rohm and Haas) for assistance with olefin polymerizations and polymer analysis, and Albemarle Corporation for the generous gift of MAO. The Bruker KAPPA APEX II X-ray diffractometer was purchased via an NSF Chemistry Research Instrumentation and Facilities: Multi-User award to the California Institute of Technology, CHE-0639094. Crystallographic data have been deposited at the CCDC,12 Union Road, Cambridge CB2 1EZ, U.K., and copies can be obtained on request, free of charge, by quoting the publication citation and the deposition numbers 600388 (2a) and 269099 (2b).

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