Molybdenum and tungsten mono-isodiazene complexes with alkyl ligands as ring-opening metathesis polymerisation procatalysts. Crystal and molecular structures of [Mo(CH_2CMe_2Ph)_3(NNPh_2)(OC_6F_5)], [W(CH_2SiMe_3)_3(NNPh_2)(OC_6F_5)] and [WCl_2(NNPh_

摘要

Reaction of [M(NNPh_2)Cl_4] with RMgCl followed by addition of pentafluorophenol afforded the tris-alkyl complexes [MoR_3(NNPh_2)(OC_6F_5)][M = Mo, R = CH_2CMe_2Ph 1; M = W, R = Ch_2SiMe_3 2] in moderate yields. At ca. 80 deg C in chlorobenzene 1 and 2 are active for the ring-opening metathesis polymerisation of norbornene; intermediate alkylidene complexes are not observed. The crystal structures of 1 and 2 have been determined; the metal centres adopt trigonal dipyramidal geometries in which the isodiazene and pentafluorophenoxide groups are apical. The crystal structure of [WCl_2(NNPh_2)(OC_6F_5)_2(thf)] 3 is also reported.