QUANTUM CHEMICAL STUDY OF TIN–SUBSTITUENT BONDS IN TRICOORDINATED TIN COMPOUNDS.

A quantum chemical study of tin–substituent bonds in tricoordinated tin compounds is conducted using the PC GAMESS-Firefly package. The structures of the studied molecules are optimized by the DFT method (B3PW91 functional; aug-cc-pVTZ-pp effective core potential basis set for tin; 6-311++(2d,p) basis set for other atoms). The wave functions and the NBOs of tin–substituent bonds are calculated with HF method using the x2c-TZVPall all-electron relativistic basis set for tin and the 6-311G(2d,2p) basis set for other atoms. Topological characteristics of tin–substituent bonds are calculated with the AIM method. It is shown that these bonds can be referred to as "intermediate type" bonds characterized by small contributions of Sn AOs to the bond MOs, large difference between the charges of tin atoms and the substituent, and low populations of bond MOs. The energies of Sn–R bonds are estimated. [ABSTRACT FROM AUTHOR]