Pentamethylcyclopentadienylmethyltitanium Silsesquioxanes and Their Zwitterionic Complexes with Tris(pentafluorophenyl)borane
Abstract
Reaction of [(eta(5)-C5Me5)TiMe3] With [(c-C5H9)(7)Si8O12(OH)] (SIPOSS) or [(c-C5H9)(7)Si7O9(OSiMe3)(OH)(2))] (DIPOSS') affords stoichiornetrically the half-sandwich titanium-disiloxy-nicthyl complexes [(eta(5)-C5Me5){(c-C5H9)(7)Si8O12O}(2) TiMe (1) and [(eta(5)-C5Me5) (c-C5H9)(7)Si7O9(OSiMe3)-O-2}TiMe] (2), respectively. Compound 2 consists orthe two stercoisonlers possessing the (eta(5)-C5Me5) ligand and OSiMe3 group in sYn- (2a) and anti-position (2b).
The more abundant 2a (2a/2b approximate to 2:1) was isolated by fractional crystallization. Compounds I and 2a reacted rapidly with B(C6F5)(3) to give zwitterionic Complexes [(eta(5)-C5Me5) (c-C5H9)(7)Si8O12O}(2)Ti]((+)) (mu-Me)B(C6F5)(3)]((-)) 3 and syn-[eta(5)- C5Me5){(c-C5H9)(7)Si7O9(OSiMe3)O-2}Ti]((+))[(mu-Me)B(C6F5)(3)]((-)) (4a), respectively...