Gas-phase reactivity of Ni⁺ with glycine

The reactions between Ni+ and glycine in the gas phase have been investigated both by means of mass spectrometry and B3LYP density functional calculations. The [Ni-glycine]+ adduct is formed in the ion source. The structure of several coordination modes of Ni+ to glycine have been determined at the B3LYP level. Calculations have shown that the ground-state structure is a bidentate η2-N,O one in which the Ni+ cation interacts with the nitrogen atom and the carbonyl oxygen. The MIKE spectrum of the [Ni-glycine]+ ion has also been analyzed and shows that the most important fragmentation corresponds to the loss of water. Other fragmentations are observed to a minor extent, namely loss of CO or loss of CH2O2. The possible mechanisms leading to these fragmentations have been studied at the B3LYP level. Among all of the mechanisms studied, the most favorable one starts with the insertion of the Ni+ metal cation into the C-C bond of the most stable η2-N,O structure.