Highly electrophilic olefin polymerization catalysts. Quantitative reaction coordinates for fluoroarylborane/alumoxane methide abstraction and ion-pair reorganization …

PA Deck, CL Beswick, TJ Marks

Index: Deck, Paul A.; Beswick, Colin L.; Marks, Tobin J. Journal of the American Chemical Society, 1998 , vol. 120, # 8 p. 1772 - 1784

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Citation Number: 198

Abstract

Reaction enthalpies of group 4 metallocenes having the general formula L2M (CH3) 2 (L= Cp, 1, 2-Me2Cp, Me5Cp; L2= Me2Si (Me4Cp)(t BuN); M= Ti, Zr, and Hf) with the strong organo-Lewis acid B (C6F5) 3 were measured using batch titration calorimetry in toluene. Methide abstraction to form the corresponding L2MCH3+ CH3B (C6F5) 3-contact ion pairs is highly exothermic in all cases. Exothermicity increases with increasing Cp methyl ...