[Me2(i-PrO)SiCH2]2SnBr2: Evidence for Intramolecular Si–O Bond Activation

The synthesis of the intramolecularly coordinated diorganotin dibromide [Me2(i-PrO)­SiCH2]2SnBr2 (2) is reported. It has been characterized by elemental analysis, electrospray mass spectrometry, 1H, 13C, 29Si, and 119Sn NMR spectroscopy, and single-crystal X-ray diffraction analysis. In compound 2 the tin atom is [4 + 2]-coordinate and shows a strongly distorted octahedral configuration. The intramolecular O→Sn coordination results in two four-membered chelate rings with Sn–O distances between 2.853(4) and 2.946(4) Å. DFT and MP2 calculations reveal these intramolecular interactions to be electrostatic. Also reported are 119Sn and 29Si NMR studies on the interaction between dimethyltin dihalides (R2SnX2; R = Me, Me2N­(CH2)3, X = Br, Cl) with trimethylethoxysilane (Me3SiOEt) and hexamethyldisiloxane (Me3SiOSiMe3), respectively.