Novel Transition-Metal (M=Cr, Mo, W, Fe) Carbonyl Complexes with Bis(guanidinato)silicon(II) Ligands

摘要

The donor-stabilized silylene 2 (the first bis(guanidinato) silicon(ii) complex) reacts with the transition-metal carbonyl complexes [M(CO)_6] (M=Cr, Mo, W) to form the respective silylene complexes 7–10. In the reactions with [M(CO)_6] (M=Cr, Mo, W), the bis(guanidinato)silicon(ii) complex 2 behaves totally different compared with the analogous bis(amidinato)silicon(ii) complex 1, which reacts with [M(CO)_6] as a nucleophile to replace only one of the six carbonyl groups. In contrast, the reaction of 2 leads to the novel spirocyclic compounds 7–9 that contain a four-membered SiN_2C ring and a five-membered MSiN_2C ring with a M-Si and M-N bond (nucleophilic substitution of two carbonyl groups). Compounds 7–10 were characterized by elemental analyses (C, H, N), crystal structure analyses, and NMR spectroscopic studies in the solid state and in solution.