Abstract
Tungsten-hexa-methyl readily reacts with B(C6F5)(3) in dichloromethane and generates the corresponding well-defined cationic tungsten-penta-methyl complex which was identified precisely by H-1 NMR, C-13 NMR, H-1-C-13 NMR correlation spectroscopy. Unlike WMe6, this cationic complex has low energy barrier to form tungsten carbene intermediate, which was further supported by the fact that WMe6 alone has no activity in olefin metathesis reaction whereas the cationic complex shows catalytic activity for self-metathesis of 1-octene.