SO ₂ Activation by the Bis(guanidinato)silylene [ i PrNC(N i Pr ₂ )N i Pr] ₂ Si: Formation of Neutral Six‐Coordinate Silicon(IV) Complexes with a Chelating Sulfito or Dithionito Ligand

Activation of SO2 by the donor-stabilized bis(guanidinato)silylene [iPrNC(NiPr2)NiPr]2Si (7) leads to the six-coordinate sulfitosilicon(IV) complex 12 (obtained by treatment of 7 with 1.5 molar equivalents of SO2 in n-hexane) or the six-coordinate dithionitosilicon(IV) complex 13 (a co-crystallizate of cis-13 and trans-13; obtained by treatment of 7 with a vast excess of liquid SO2). Compounds 12 and 13 were characterized by elemental analyses, crystal structure analyses, and multinuclear NMR spectroscopic studies in the solid state and in solution. The six-coordinate silicon(IV) complexes 12, cis-13, and trans-13 represent very rare examples of main-group element compounds with an O,O-chelating sulfito or dithionito ligand.