Structure and 35Cl NQR parameters of 1,3-diphenyl-3-methyl-3-(trichlorogermyl)butanone-1 using ab initio calculations

Abstract

Quantum-chemical calculations at the RHF/6-31G(d) and MP2/6-31G(d) levels of two stable structures of 1,3-diphenyl-3-methyl-3-(trichlorogermyl)butanone-1 molecule were executed. According to calculations at the RHF/6-31G(d) level, the structure with pentacoordinated Ge atom is by 7.49 kJ/mol energetically more advantageous as compared with that with the tetracoordinated one. Using 3 p -components of the Cl atom valence p -orbitals obtained from these calculations, the 35 Cl nuclear quadrupole resonance (NQR) parameters of this compound with the pentacoordinated Ge atom were assessed. Calculations performed at both the RHF/6-31G(d) and MP2/6-31G(d) levels do not differ principally and are close to experimental NQR data. Calculations at the RHF/6-31G(d) level performed at various Ge ‧ ‧ ‧ O distances demonstrated that convergence of the Ge and O coordination centers leads to an increase in the positive charge at the Ge atom and in the negative charge at the O atom, and with that, electron density from the Ge atom shifts mainly to the axial Cl atom and from the C atom of carbonyl group to its O atom. On such convergence, the electron density of atoms directly bonded to those of the Ge coordination polyhedron decreases to some extent.