Coordination chemistry of Si5Cl10 with organocyanides

Abstract

Organocyanides readily coordinate to decachlorocyclopentasilane (Si₅Cl₁₀) to form “inverse sandwich” compounds 1–3 with a planar Si₅ ring. The products were isolated in high yield and fully characterized by elemental analysis, multinuclear NMR, IR and UV-Vis spectroscopy. While the spectroscopic data suggests the presence of a fairly weak interaction between the Si₅ ring and the coordinative organocyanide ligands, single-crystal X-ray diffraction studies of compound 1 and 2 show μ₅-coordination of the apical cyano nitrogen atoms to the silicon atoms in the Si₅ ring. Distances between silicon atoms and nitrogen atoms are significantly shorter than a Si–N van der Waals bond but longer than the sum of their covalent radii. Multiple interactions between the cyano groups and equatorial Cl atoms, and intermolecular interactions were observed in the solid state for both compounds 1 and 2.