Isobutene–isoprene copolymerization initiated by [Cp∗MMe2][(n-C18H37E)B(C6F5)3] (M=Ti, Hf; E=O, S) and related compounds

Cationic half‐sandwich scandium complex for the synthesis of polyisobutylene with high molecular weight under mild conditions

“…In the past decades, the application of weak Lewis acids (such as B(C 6 F 5 ) 3 , Al(C 6 F 5 ) 3 and [Ph 3 C][B(C 6 F 5 ) 4 ]), which can generate weakly coordinating counteranions, has aroused great interests in the synthesis of high M n polyisobutylene under mild conditions, because the low nucleophilicity of these counteranions can restrict side reactions in the cationic polymerization . Particularly, well‐defined group 4 metallocene complexes (Ti, Zr, and Hf) with weakly coordinated counteranions can achieve high M n polyisobutylene at mild conditions, but isobutylene conversions were limited (10–60%) . While the half‐sandwich titanium complex (C 5 Me 5 )TiMe 3 can serve as a highly effective cationic catalyst system for isobutene polymerization activated by [Ph 3 C][B(C 6 F 5 ) 4 ] at −30 °C, there are currently no more detailed information about copolymerization…”