Coordinative Dimerization of Aminosilanes. Model MNDO and Ab Initio Molecular Orbital Calculations

Abstract

The possibility of formation of cyclodisilazanes by the coordinative dimerization of aminosilanes has been investigated by MNDO and ab initio (3–21G(*)) methods. It has been shown that this process is mainly controlled by the silicon centers through their charges and acceptor orbitals. One chlorine (Br,I) at silicon makes available a low energy acceptor orbital which afford a reasonable low barrier to dimerization. One fluorine at silicon raises the energy of the proper symmetry acceptor orbital to such a level that no dimerization can be detected by MNDO. More fluorine substituents enhance the electrostatic attractive interactions which coupled with some lowered acceptor orbitals make feasible the formation of 2,2,2,4,4,4 hexafluorodisilazanes.