Organo-Lewis acids as cocatalysts in cationic metallocene polymerization catalysis. Unusual characteristics of sterically encumbered tris(perfluorobiphenyl)borane
- Northwestern Univ., Evanston, IL (United States)
Organo-Lewis acids such as methylalumoxane (MAO) and B(C{sub 6}F{sub 5} ){sub 3} (I) play pivotal roles as alkide/hydride abstractors/ cocatalysts in generating highly active, cationic olefin polymerization catalysts (II; L,L` = anionic ancillary ligands; X{sup -} = weakly coordinating anion). We communicate here the unusual cocatalytic characteristics of the new, sterically encumbered fluoroarylborane, tris(2,2`,2``-perfluorobiphenyl)-borane (PBB, III). Characteristics include substantially different abstractive and ion pair structure/reactivity relationships vis-a-vis I. PPB was synthesized as colorless microcrystals in 76% yield from C{sub 6}F{sub 5}Br. Reaction with group 4 and Th methyls proceeds cleanly to yield cationic complexes, which were characterized by standard {sup 1}H/{sup 13}C/{sup 19}F NMR spectroscopic and analytical techniques. The results illustrate the substantial and surprising differences in cationic complex ion pair structure and reactivity that can be brought about by modifications in fluoroarylborane catalyst architecture. 10 refs., 1 fig., 1 tab.
- DOE Contract Number:
- FG02-86ER13511
- OSTI ID:
- 447213
- Journal Information:
- Journal of the American Chemical Society, Journal Name: Journal of the American Chemical Society Journal Issue: 49 Vol. 118; ISSN JACSAT; ISSN 0002-7863
- Country of Publication:
- United States
- Language:
- English
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