Enhanced acidity of Zn2+ in the presence of small numbers of water molecules.
Experiments performed on gas phase [Zn(H2O)N]2+ complexes, for N in the range 4-7, show the ions readily undergo unimolecular (metastable) decay with respect to proton release via the reaction [Zn(H2O)N]2+--> Zn(2+)OH(-)(H2O)M + H3O(+)(H2O)N-M-2. To account for these products, it is proposed that the larger complexes have a stable [Zn(H2O)4]2+ core to which additional molecules are retained in an outer shell through hydrogen bonding. At N = 7, this arrangement would make it possible for proton release to be associated with a chain of up to four water molecules, which equates with ideas proposed for the activity of Zn2+ in metalloenzymes.
Xiaojing
X
Chen
Guohua
G
Wu
Bohan
B
Wu
Bridgette J
BJ
Duncombe
Anthony J
AJ
Stace