Interactions of dopamine and dopamine hydrochloride with ethanol

Cyclic voltammetry (CV), density functional theory (DFT) calculations, and atoms in molecules (AIM) analyses were performed to investigate the hydrogen bonding in dopamine-ethanol and dopamine hydrochloride-ethanol mixtures. CV results show that the anodic/cathodic peak potential of dopamine hydrochloride in ethanol is influenced by the hydrogen bonding formed in the mixtures. The DFT and AIM results indicate that the hydrogen atoms of -NH3+ in dopamine hydrochloride-ethanol system are easier to interact with ethanol by hydrogen bonding than those in dopamine-ethanol system. On the contrary, the hydrogen atoms on phenolic hydroxyl groups can form stronger hydrogen bonding with ethanol in dopamine-ethanol system than in dopamine hydrochloride-ethanol system. (C) 2016 Elsevier B.V. All rights reserved.