Dehydrogenation reactions in Mg[sup +](H[sub 2]O)[sub [ital n]] clusters

Experimental observations of the effects of solvation on the dehydrogenation reaction of Mg[sup +](H[sub 2]O)[sub [ital n]] to produce MgOH[sup +](H[sub 2]O)[sub [ital n][minus]1] are presented for [ital n][le]6. The reaction is seen to occur spontaneously at room temperature for [ital n][gt]4. Ligand switching reactions are used to show the Mg[sup +]--OH bonds are stronger than Mg[sup +]H[sub 2]O bonds. The results show the energy required to lose an H atom decreases with the number of water molecules attached because the magnesium changes oxidation state and this results in stronger interactions with the water ligands. [ital Ab] [ital initio] calculations are used to explain these observations.