Molecular Modeling and Spectroscopic Investigation of Tyramine and Its Monohydrate Cluster: A DFT Approach

Abstract

AbstractThis study has performed molecular modeling, vibrational dynamics, and thermodynamics of tyramine neurotransmitter and its monohydrate cluster in gas phase. All theoretical calculations for tyramine and its monohydrate cluster are performed at DFT/B3LYP/6‐31++G(d,p) level to optimize the electronic structures and calculation of vibrational frequencies. Most of the vibrational frequencies have been found in good agreement with the experimentally reported IR and Raman frequencies. However, some have been modified. The presence of water monomer decreased highest molecular orbital–lowest unoccupied molecular orbital (HOMO–LUMO) energy gap of tyramine by 0.07 eV. Themodynamics calculations reveal that thermal energy and specific heats in both the tyramine and its monohydrate clusters are predominantly contributed by vibrational motions while entropy shows only 28% and 26% vibrational contribution in tyramine and its monohydrate cluster, respectively.