Theoretical Study of α/β-Alanine and Their Protonated/Alkali Metal Cationized Complexes

Abstract

Density functional theory has been employed to model the structure and the relative stabilities of α/β-alanine conformers and their protonated and alkali metal cationized complexes. In general, we find that the behavior of the β-alanine (β-Ala) system is quite similar to that of α-alanine (α-Ala). However, the presence of the methylene group (-CH 2-) at the β position in β-Ala leads to a few key differences. First, the intramolecular hydrogen bonding patterns are different between free α- and β-Ala. Second, the stability of zwitterionic species (in either the free ligand or alkali metal cationized complexes) is often enhanced in β-Ala. Third, the preferred mode of alkali metal cation (M +) binding may also differ in α- and β-Ala. Natural energy decomposition analysis has been applied here to gain further insight into the effects of the ligand, cation size, and mode of binding on the nature of interaction in these M +-Ala complexes.Department of Applied Biology and Chemical Technolog