Electronic structures of intermolecular hydrogen bond contacts with solute in aqueous solution: glycine as a working prototype

Abstract

The intermolecular hydrogen bond (H-bond) interactions play vital roles in many biological systems. Despite continued interest, the nature of their electronic structures has remained elusive. Based on the unique features of aqueous solution, a simple model depicting the H-bond electronic states by orbital hybridizations is developed. The model is demonstrated by reproducing the experimental IR data and yielding favorable solute–solvent interactions for the prototype glycine. The H-bond state for solute H, O and N atoms is found to be characterized by sp¹, sp², and sp³ hybridizations, respectively. The model provides a new way for probing the intricate solute–solvent contacts.