Effect of regular hydration on gas phase structural stability of [zwitterionic alanine+M+] (M+Â =Â Li+, Na+, K+) complexes: A quantum chemical study

► Effect of regular hydration on gas phase structural stability of differently coordinated Ala-M+ and ZAla-M+ (M+ = Li+, Na+, K+) complexes has been studied. ► Five water molecules are needed to stabilize the -OO coordinated structure of ZAla-M+ over-NO/OH coordinated structures of Ala-M+ complex. ► Planarity of the ZAla-M+ complexes does not change by the addition of five water molecules. ► Loss of entropy by the stepwise addition of water molecules confirms that the hydrated species are more stable.