Preparation and characterization of functional disilaalkanes: Supramolecular motifs in the crystal structures of Ph3SiCH2CH2SiRR2′ [R = Me, R′ = Cl; R = R′ = Ph] mediated by C–H⋯Cl and/or C–H⋯π interactions

The hydrosilylation reaction between equimolar quantities of triphenylsilane and dichloromethyl/dichlorophenyl/trichlorovinylsilane in the presence of Karstedt’s catalyst (10−5 mol Pt/mol of silane) affords the corresponding disilaalkanes, Ph3SiCH2CH2SiRR2′ [R = Me, R′ = Cl (1); R = Ph, R′ = Cl (2); R = R′ = Cl (3)], along with minor amounts of Ph3SiCH2CH2SiPh3 (4) as a result of redistribution of the ligands at silicon (vinyl/H exchange). On the other hand, the analogous reaction between triphenylsilane and triethoxyvinylsilane proceeds without ligand exchange to yield the disilaalkane, Ph3SiCH2CH2Si(OEt)3 (5) as the sole product, which upon subsequent treatment with lithium aluminium hydride gives Ph3SiCH2CH2SiH3 (6). X-ray crystal structures of 1 (monoclinic, P21/c) and 4 (triclinic, P1¯) reveal a trans planar conformation of the Si–C–C–Si unit and propeller-shape stereochemical arrangement of the triphenylsilyl fragment. These molecules self assemble into 3-D supramolecular motifs via C–H⋯Cl and/or C–H⋯π interactions.

The syntheses of the disilaalkanes Ph3SiCH2CH2SiRR2′ [R = Me, R′ = Cl (1); R = Ph, R′ = Cl (2); R = R′ = Cl (3), Ph (4), OEt (5), H (6)] along with the crystal structures of 1 and 4 are described.Figure optionsDownload as PowerPoint slide