A Comprehensive Picture of the Structures, Energies, and Bonding in [SO(HO)], = 1-6.

Two stochastic methods in conjunction with ab initio computations were used to explore the potential energy surfaces for the microsolvation of SO with up to six explicit water molecules. At least three water molecules are needed to stabilize the Coulomb repulsion that prevents the existence of isolated SO. The formal charge in SO is strong enough to induce water dissociation and subsequent microsolvation of the resulting HSO, OH ionic pair. Hydrogen bonds characterized as having complex contributions from covalency and from ionicity are at play stabilizing [SO(HO)] clusters. Ionicity and covalency act concomitantly rather than opposedly to strengthen both intermolecular interactions and the resulting O-H bond in HSO after proton abstraction.