LAUSR

A series of (imido)vanadium(V)-alkylidene complexes containing pentachlorophenoxy ligand of type, V(CHSiMe3)(N-2,6-R2C6H3)(OC6Cl5)(PMe3)2 [R = H, Cl, F, CH3], have been prepared, and the structure of V(CHSiMe3)(N-2,6-Me2C6H3)(OC6Cl5)(PMe3)2 was determined by X-ray crystallographic analysis. Ring-opening metathesis polymerization (ROMP) of cyclic olefins such as norbornene (NBE), cyclopentene (CPE), cycloheptene (CHPE), and cis-cyclooctene (COE) using these alkylidene catalysts have been explored, and V(CHSiMe3)(N-2,6-Cl2C6H3)(OC6Cl5)(PMe3)2 showed higher activities in the ROMP of CPE, CHPE, and COE than those of the reported V(CHSiMe3)(N-2,6-Cl2C6H3)(OC6F5)(PMe3)2. The activity in the ROMP of COE increased at high temperature until 120 °C, and the ROMPs of CHPE and COE proceeded without chain-transfer or termination (nor catalyst decomposition); the (quasi) living nature thus maintained even at 80 °C. The activities in the ROMPs of CHPE and COE (at 25 °C) increased upon addition of 1.0 equiv of B(C6F5)3, ...