Stereoelectronic srtructure of γ-chloropropyltrichlorostannane. Ab initio calculation

Abstract

The quantum-chemical calculations by the RHF/3-21G* and MR2/3-21G* methods of the Cl(CH2)3SnCl3 and ClCH2SnCl3 molecules with full optimization of their geometry was performed. The Cl(CH2)3SnCl3 molecule was also calculated by the RHF/3-21G* method at different distances between the Sn atom and the Cl atom in the C-Cl fragment. From the results of the calculations 35Cl NQR frequencies were estimated and the electric field gradient asymmetry parameters at the 35Cl nuclei of these molecules. The abnormally high electron density on the Cl atom of the C-Cl fragment in the Cl(CH2)3SnCl3 molecule is due mainly to the polarization of this compound under the influence of significant positive charge on the Sn atom directly through the field. The polarization of the C-Cl bond in the molecule is of the opposite direction to the polarization of the related bond in the ClCH2SnCl3 molecule because of the peculiarities of their geometries. The transfer of the electron density from the Cl atom of the C-Cl fragment to the Sn atom in the Cl(CH2)3SnCl3 molecule is not observed.