Harmony and Dissonance in the Concert of Proton Motions

摘要

The motion of a proton between donor and acceptor atoms is one of the simplest chemical reactions, and an overall reaction involving two such motions within the same molecular array represents the simplest case in which, to consider the coupling of two chemical processes; do they occur simultaneously in time (concertedly) or serially in time (in a stepwise manner)? Reactions in which multiple (often two) proton-transfer events among electronegative atoms such as O, N, and S accompany bonding changesin a framework of atoms heavier than H are of interest in biology as well as chemistry, for example in the action of enzymes and in tautomerization reactions in nucleic-acid base pairs. Several recent studies have begun to illuminate the manner in whichthe molecular choice between concerted and stepwise motion of the protons is made.