DFT Investigations of Charge Transfer Complexes Formed between Naphthols with 1,3-Dinitrobenzene: Conformational, Structural, Electronic, Thermodynamic, and Spectroscopic Insights

A charge transfer complex (CTC) is created through the interaction between a donor molecule and an acceptor molecule. This research delves into density functional theory (DFT) investigations focusing on the molecular structures, electronic properties, and spectroscopic analyses of CTCs formed by the interaction of 1-naphthol and 2-naphthol with 1,3-dinitrobenzene as a π-electron acceptor. These complexes have not been synthesized; this study helps for future experimental work. The study employs the B3LYP/6-311++G(d,p) method to explore aspects like conformational analysis of naphthols, energy gaps between rotamers, molecular structures, electronic distributions, electric moments, thermodynamic parameters, frontier molecular orbitals (FMOs), molecular electrostatic maps, optical characteristics, UV-Vis, and IR spectroscopy analysis of CTCs in the gas phase. The free rotation around the O-aryl for naphthols was examined, resulting in the identification of syn and anti-rotamers. Thermodynamic parameters suggested stability of the complexes, with non-spontaneous and exothermic creation processes. Electric moments indicated significant charge separation, suggesting potential for nonlinear optical applications. The absorption spectrum of CTCs exhibits specific bands representing transitions from the ground state to higher energy states, observable as absorbance peaks in UV-visible spectra.