Proton transfer

Transfer of a hydrogen nucleus from a donor to an acceptor. Electron-pair bookkeeping distinguishes transfer of ${\mathrm{H}}^{+}$ from transfer of a hydride equivalent.

A proton relay transfers a proton through a sequence of neighboring donors and acceptors, often including water. The full catalytic sequence must regenerate the relay groups; a static hydrogen-bond diagram does not determine its direction or timing.