Implicit allowance for “specific” hydrogen bonding contributions to hydration energies in quantum chemically based continuum models: a phenomenological perspective

The abilities of some quantum mechanically based continuum models to accurately predict hydration energies, even where “specific” hydrogen bonding interactions to the aqueous solvent are anticipated, suggests that such effects are implicitly allowed for in the electrostatic model. Examples of this phenomenon involving various ’onium ions are presented and discussed in the context of COSMO, SM2, and a revised version of the authors’ previously described PCM method.