Tetravalent Oxygen and Sulphur Centres Mediated by Carborane Superacid: Theoretical Analysis.

The tetravalent oxygen or sulphur centres, especially in H4 O2+ and H4 S2+ dications, were analysed experimentally and theoretically in various studies. Herein, we discuss stabilities of such centres in related H(CH3 )3 O2+ and H(CH3 )3 S2+ dications mediated by carborane superacid. The ωB97X-D/6-311++G(d,p) calculations were performed for a gas phase and for different solvents characterized by a wide range of dielectric constants for complexes of these dications with the conjugated base of H(CHB11 F11 ) carborane superacid, CHB11 F11 - , which indicate that these complexes are linked by hydrogen bonds. The Quantum Theory of 'Atoms in Molecules' (QTAIM) approach is applied to characterize these interactions. DFT results show that tetravalent oxygen and sulphur structures are additionally stabilized by polar solvents.