Pentafluorophenylimido Alkylidene Complexes of Molybdenum and Tungsten

Pentafluorophenylimido alkylidene complexes of molybdenum and tungsten have been prepared in good yields. Examples include Mo(NC6F5)(CHCMe2Ph)(Me2Pyr)2 (Me2Pyr = 2,5-dimethylpyrrolide), W(NC6F5)(CH-t-Bu)(DME)(Pyrrolide)2, Mo(NC6F5)(CHCMe2Ph)[OC(CF3)3]2, W(NC6F5)(CH-t-Bu)(DME)[OC(CF3)3]2, Mo(NC6F5)(CHCMe2Ph)[OC(C6F5)3]2, W(NC6F5)(CH-t-Bu)[OC(C6F5)3]2, Mo(NC6F5)(CHCMe2Ph)(ODFT)2 (ODFT = O-2,6-(C6F5)2C6H3), and W(NC6F5)(CH-t-Bu)(ODFT)2. Treatment of W(NC6F5)(CH-t-Bu)(DME)[OC(CF3)3]2 with ethylene led to formation of W(NC6F5)(CH2CH2CH2)[OC(CF3)3]2, which has a TBP structure in which the metallacyclobutane ring lies in the equatorial plane. 2,3-Dicarbomethoxynorbornadiene is polymerized by M(NC6F5)(CHR′)(ODFT)2 initiators to give cis,isotactic-poly(DCMNBD).