ACID-BASE CATALYZED-REACTIONS IN IONIC WATER CLUSTERS

Fourier Transform-Ion Cyclotron Resonance (FT-ICR) mass spectrometric studies of both cationic water clusters H+(H2O)(n), n = 1-70, and anio nic water clusters X-(H2O)(n), n 1-30, X = OH, O, with acetone and ace taldehyde are reported. For the cations a sequence of ligand exchange and fragmentation reactions results in ''solvated proton'' complex ion final products. In the anionic OH-(H2O)(n) clusters, on the other han d, an OH- catalyzed aldol addition of the carbonyl compounds with a tr ue covalent bond formation is observed. The anionic and cationic water clusters thus behave similar to basic and acidic aqueous solutions.