On the Properties of Siδ+Hδ-···Yδ- (YO, S) Interactions Involving Hydridic Hydrogen.

Abstract

Si^δ+H^δ-···Y^δ- (YO, S) interactions involving hydridic hydrogen are analyzed in the complexes SiF₃H:Oxirane and SiF₃H:DME and SiF₃H:Thiirane and SiF₃H:DMS by applying quantum chemistry calculations as well as Bader's Quantum Theory of Atoms In Molecules (QTAIM). The weak Si^δ+H^δ-···Y^δ- (YO, S) contacts are characterized as weak van der Waals interactions instead of true bonding interactions, as is consistent with the small bond order and electron delocalization indices. The QTAIM results predict a dominant closed shell (ionic) interaction. The energy decomposition analyses reveal that in general the complexes are sterically stabilized, whereas a dominant destabilizing contribution comes from the Pauli repulsion term. The stabilizing/destabilizing contributions of other energy components (electrostatic and exchange correlation effects) are found to depend on the level of computation used. The present study also focuses on revealing the effects of the incorporation of dispersion correction and long-range correction terms for Coulombic interactions into the quantum chemistry results by suitably selecting the density functionals used for calculations, and the results are compared with those predicted by second-order Møller-Plesset (MP2) perturbation theory.