Nature of Coordination Bond in 1-Chlorogermatrane and Dynamic of its Formation Based on Ab Initio Calculations

Quantum-chemical calculations were performed for the 1-chlorogermatrane at the MP2/6-31G(d) level with total optimization of its geometry and at different fixed Ge…N distances (from 2.0 to 3.8 Å) and fixed rights (90º) CNGe angles. The coordination bond in this molecule is a result of participation of different AO’s of N and Ge atoms (along with orbitals of other atoms of the molecule) in the formation of a series of MO’s. Formation of MO existing only at the Ge…N distance of the totally optimized molecule plays the most essential role. On formation of the coordination bond, electron density shifts from the electron-donor fragment of a molecule to the electron-acceptor one, but not from “electron-donor center” on the “electronacceptor” one. At this point, a negative charge of the N atom increases. Coordination centers serve as conductors of this electron density. Populations of s- and р-orbitals of the N atom depend essentially on CNGe angles.

Keywords: 1-Chlorogermatrane, coordination bond, nature and dynamic of formation, ab initio calculations, molecular orbitals, electron density.