Concerted proton migration along short hydrogen bonded water bridges in bipyridine-water clusters.

The outcome of reactions between D(2)O and size-selected ionic clusters of the type MH(+)(H(2)O)(n) (M = bipyridine, n = 1-30) shows that H-D-exchange is significantly higher for 2,2'-bipyridines than for 4,4'-bipyridines. This gives strong support for the idea that the existence of short water wires between the two nitrogen sites is essential to proton migration in water clusters containing basic sites.