Synthesis of Early Transition Metal Bisphenolate Complexes and Their Use as Olefin Polymerization Catalysts
Bisphenolate ligands with pyridine- and benzene-diyl linkers have been synthesized and metalated with group 4 and 5 transition metals. The solid-state structures of some of the group 4 complexes have been solved. The titanium, zirconium, hafnium, and vanadium complexes were tested for propylene polymerization and ethylene/1-octene copolymerization activities with methylaluminoxane as cocatalyst. The vanadium(III) precatalyst is the most active for propylene polymerization and shows the highest 1-octene incorporation for ethylene/1-octene copolymerization. The zirconium(IV) precatalyst was the most active for propylene polymerization of the group 4 precatalysts. Titanium(IV) and zirconium(IV) precatalysts with pyridine-diyl linkers provided mixtures of isotactic and atactic polypropylene while titanium(IV) precatalysts with benzene-diyl linkers gave atactic polypropylene only. The hafnium(IV) precatalyst with a pyridine-diyl linker generated moderately isotactic polypropylene.
Additional Information© 2009 American Chemical Society. Received July 28, 2009; Revised Manuscript Received October 15, 2009. Publication Date (Web): October 29, 2009 Supporting Information Available: Additional tables, figures, and all CIFs. This material is available free of charge via the Internet at http://pubs.acs.org. This work has been supported by the USDOE Office of Basic Energy Sciences (Grant DE-FG03- 85ER13431). The authors thank Lawrence M. Henling and Michael W. Day of Caltech for mounting and solving the crystal structures. We also acknowledge Dr. Sara B. Klamo of The Dow Chemical Company for assistance with polymer characterization. The Bruker KAPPA APEXII X-ray diffractometer was purchased via an NSF CRIF:MU award to the California Institute of Technology, CHE-0639094.
Supplemental Material - Golisz2009p6449Macromolecules_supp.pdf
Supplemental Material - ma901659q_si_002.cif