Stereoelectronic structure of 3-(trichlorogermyl)propionic acid by the results of ab initio calculations

Abstract

Two structures of the 3-(trichlorogermyl)propionic acid molecule and its dimer were calculated by the RHF/6-31G(d) method with the full geometry optimization. The structure with pentacoordinated germanium atom is by 4.71 kcal mol−1 more favorable than that with tetracoordinated germanium. The strength of coordination bond in the first structure increases with the absolute values of charge on the Ge and O coordination centers. The relatively small values of these charges result in a weak coordination bond. In the first structure, this bond is weaker than in the dimer, since the Ge…O distance in it (3.016 A) is larger than in the latter (2.898 A). This bond is formed due to the rapproachment of the Ge and O coordination centers at their electrostatic interaction. This provides the transfer of electron density from the atoms of the donor fragment of the molecule to the atoms of the germanium coordination polyhedron. The coordination centers serve as the conductors for the electron density transfer.