Influence of the polarity of the medium on the electronic structure and energetics of molecules in solutions

Recent data on the effect of the polarity of the medium on the states of solute molecules having different types of chemical bond in are reviewed. The changes in electronic structure and in the energetics of the molecules are discussed, and their influence in the physicochemical properties and role of the molecules in various liquid-phase processes (tautomeric and conformational transformations, nucleophilic substitution, proton transfer) is examined. Special attention is paid to the new concept of preferential stabilisation of molecular and of ionic forms of salts and of complexes with intermolecular hydrogen bonds in media of different polarity. The bibliography includes 98 references.