Solvent-induced interactions: Hydrophobie and hydrophilic phenomena

The solvent-induced interactions between two kinds of molecules (or groups) are examined from the point of view of the solvation free energies of a pair of interacting molecules (or groups). The first interaction is that between two simple nonpolar solutes (or groups) in water and is known as the hydrophobic interaction. Both theoretical as well as experimental evidence indicate that these interactions are quite weak. The solvent-induced interactions between two functional groups that can form hydrogen bonds, referred to as intramolecular hydrophilic interactions, are found to be much stronger than the corresponding hydrophobic interactions. It is therefore argued that intramolecular hydrophilic interactions are probably more significant in biochemical processes than hydrophobic interactions.