A vanadium(V) alkylidene complex exhibiting remarkable catalytic activity for ring-opening metathesis polymerization (ROMP)

The vanadium(V) alkylidene complex (ArN)V(=CHSiMe3)(N=(CBu2)-Bu-t)(PMe3) (6,Ar = 2,6-Me2C6H3) has been isolated from (ArN)V(CH2SiMe3)(2)(N=(CBu2)-Bu-t) (5) by alpha-hydrogen elimination in benzene-d(6) at 80 degrees 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 x 10(6), M-w/M-n = 1.6) in high yield (98%), and the activity increased at higher temperatures (80 degrees C).