Communication: Where does the first water molecule go in imidazole?

Abstract

Supersonic jet FTIR spectroscopy supplemented by 18O substitution shows unambiguously that water prefers to act as an O-H·N hydrogen bond donor towards imidazole, instead of acting as a N-H ·O acceptor. Previous matrix isolation, helium droplet, and aromatic substitution experiments had remained ambiguous, as are standard quantum chemical calculations. The finding is supported by a study of the analogous methanol complexes and by higher level quantum chemical calculations. © 2011 American Institute of Physics.