Multiple coupling of silanes with imido complexes of Mo

Abstract

The bis(imido) complexes (^tBuN)₂Mo(PMe₃)(L) (L = PMe₃, C₂H₄) react with up to three equivalents of silane PhSiH₃ to give the imido-bridged disilyl silyl Mo(VI) complex (^tBuN){μ-^tBuN(SiHPh)₂}Mo(H)(SiH₂Ph)(PMe₃)₂ (3) studied by NMR, IR and X-ray diffraction. NMR data supported by DFT calculations show that complex 3 is an unusual example of a silyl hydride of Mo(VI), without significant Si⋯H interaction. Mechanistic NMR studies revealed that silane addition proceeds in a stepwise manner via a series of Si–H⋯M agostic and silanimine complexes whose structures were further elucidated by DFT calculations.