Highly active, stable, and selective well-defined silica supported Mo imido olefin metathesis catalysts

Grafting 2 [Mo( NAr)(=CHCMe2R1)(NR2)(2)] on SiO2-(700) gives selectively [( SiO)Mo( NAr) (= CHCMe2R1)(NR2)] (1), according to mass balance analysis, IR, and NMR spectroscopies. The replacement of one amido group by a siloxy group from the surface of silica dramatically increased the reactivity of the Mo complex in olefin metathesis, and the remaining amido ligand brings stability and selectivity to the system as evidenced by the absence of formation of 1-butene in the metathesis of propene and the high turnovers obtained for the metathesis of ethyl oleate.