Grafting Of Group 6 Imido–Alkyl Complexes on Silica: Mo vs. W

Grafting of the isostructural imido–alkyl complexes M(=NMes)2(CH2CMe2Ph)2 (M = Mo (1), W (2); Mes = 2,4,6-Me3C6H2) onto the surface of SiO2 partially dehydroxylated at 700 °C and physicochemical study (mass balance, IR, EA, SSNMR) of resulting materials 1s and 2s are presented. While for molybdenum complex, grafting primarily proceeds via cleavage of the alkyl group, protonation of the imido ligand becomes a predominant pathway for the tungsten counterpart. The catalytic activity of 1s and 2s in oxo/imido heterometathesis is also determined and compared with the previously reported systems.