Cohydrolysis of Organotin Chlorides with Trimethylchlorosilane. Okawara's Pioneering Work Revisited and Extended

Abstract

The synthesis of the stannasiloxanes {[R2(Me3SiO)Sn]2O}2 (1, R = Me; 2, R = Et), [R2(Me3SiO)Sn]2O (8, R = Me3SiCH2; 9, R = t-Bu), R2Sn(OSiMe3)2 (3, R = i-Pr; 4, R = Me3SiCH2; 5, R = t-Bu; 6, R = Cp(CO)3W; 7, R = Cp(CO)2Fe), and [Cp(CO)2Fe]2Sn(OSiPh3)2 (7a), the monoorganotin trichloride Me3SiCH2SnCl3 (13), and the organotin oxocluster (Me3SiCH2Sn)12O14(OH)6Cl2 (14) is reported. Their identity was confirmed by both solution and solid state multinuclear NMR spectroscopy and in the case of 1, 2, 6, 7a, and 14 also by single-crystal X-ray analyses. A spinning sideband analysis of the 119Sn MAS spectra reveals the coordination geometries of the tin atoms in the stannasiloxanes 1 and 2 to be different from those of related diorganotin oxides (R2SnO)n (R = Me, Et). In solution, 1 and 2 exhibit an intramolecular exchange process as well as monomer−dimer equilibria. The reaction of 4 with cyclo-(t-Bu2SnO)3 and of cyclo-[(Me3SiCH2)2SnO]3 with cyclo-(t-Bu2SnO)3 provided evidence for the formation in situ of the mixe...