Pentafluorophenylimido Alkylidene Complexes of Molybdenum and Tungsten

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