Structure of cationized glycine, Gly.M(super 2+) (M = Be, Mg, Ca, Sr, Ba), in the gas phase: intrinsic effect of cation size on zwitterions stability

The intrinsic effect of divalent alkaline earth metal ions (Be, Mg, Ca, Sr, Ba) on the structure of glycine in the absence of solvent is examined. In the presence of larger multivalent ions, stable zwitterions and salt-bridge structures play an important role in the gas-phase structure and chemistry of these ions.