Special features of intermolecular bondingA...D(A= Si, Ge andD= nucleophile) in crystal structures

Abstract

An investigation of the crystal structures of 3346 silicon- and 718 germanium-containing compounds was carried out with a geometrical–topological analysis. The descriptors of inter- and intramolecular contactsA...Dare given. Information on the descriptors ofT—A...D(whereT= leaving group) interactions in terms of a stereoatomic model of crystal structures was described as being helpful in modelling SN2 reactions. It was established that the formation of multiple intermolecular contacts in crystal structures is unfavorable. The dependence of the descriptors of intermolecular contactsT—A...D was studied as a function of the nature ofT(leaving group in substitution reactions) andD(nucleophile atom or group of atoms) groups, and the coordination number of anAatom. The constancy of theT—AandA...Dbond-order sum in crystal structures was demonstrated.