A Vanadium(V) Alkylidene Complex Exhibiting Remarkable Catalytic Activity for Ring-Opening Metathesis Polymerization (ROMP)

The vanadium(V) alkylidene complex (ArN)V( CHSiMe 3 )(N C t Bu 2 )(PMe 3 ) ( 6; Ar = 2,6-Me 2 C 6 H 3 ) has been isolated from (ArN)V(CH 2 SiMe 3 ) 2 (N C t Bu 2 ) ( 5 ) by α-hydrogen elimination in benzene- d 6 at 80 °C. The complex 6 initiated ring-opening metathesis polymerization (ROMP) of norbornene, yielding a high-molecular-weight polymer with unimodal molecular weight distribution ( M w = 1.15 × 10 6, M w / M n = 1.6) in high yield (98%), and the activity increased at higher temperatures (80 °C).