Reactions of the donor-stabilized silylene bis[N,N'-diisopropyl-benzamidinato(-)]silicon(II) with Brønsted acids.

Reaction of the donor-stabilized silylene 1 (which is three-coordinate in the solid state and four-coordinate in solution) with [HMCp(CO)3 ] (M=Mo, W; Cp=cyclopentadienyl) leads to the cationic five-coordinate silicon(IV) complexes 2 and 3, respectively, and reaction of 1 with CH3 COOH yields the neutral six-coordinate silicon(IV) complex 4. Compounds 2-4 were structurally characterized by crystal structure analyses and multinuclear NMR spectroscopic studies in the solid state and in solution. The formation of 2-4 can be formally described in terms of a Brønsted acid/base reaction, coupled with a redox process (Si(II) →Si(IV) , H(+) →H(-) ).