Deuterium isotope effect on gas phase ion-molecule hydrogen-bonding interactions: multiply solvated fluoride, chloride, and alkoxide ions

Fourier transform ion cyclotron resonance (FTICR) measurements of solvent e xchange equilibria, where the solvents differ only by a single deuterium su bstitution at the labile hydroxylic site, have been used to study the deute rium isotope effect on ion-molecule hydrogen-bonding interactions. The syst ems studied include chloride ion, fluoride ion, and alkoxide ions solvated by up to three molecules of alcohol: (ROH)(n) . Cl-, (ROH)(n) . F-, and (RO H)(n) . RO-. Differences in the measured isotope effects are explained on t he basis of the differing hydrogen bond strengths in the adducts and by the ability of the chloride ion to partake in multiple site interactions. (Int J Mass Spectrom 199 (2000) 127-139)(C) 2000 Elsevier Science B.V.