EFFECTS OF SOLVENTS ON THE ELECTRONIC AND MOLECULAR PROPERTIES OF 4-((2-METHYL-4-NITROPHENYL)IMINO)METHYL)PHENOL

Abstract

Schiff bases are known to possess antiviral, antifungal, antibacterial, enzymatic and other significant biological properties. They also chelate metals to form complexes that have been used in industrial processes. Schiff bases are also important in modern energy applications due to their photometric and thermochemical properties. The basis of their applications depends on the molecular and electronic properties hence it is important to study how solvents perturb these properties. Therefore, this work is aimed at studying the electronic and molecular properties of a Schiff base. The effects of solvents on 4-(((2-methyl-4-nitrophenyl)imino)methyl)phenol was investigated both experimentally and theoretically. Experimentally, the UV-Visible spectrophotometer was used to obtain the absorption spectra of the compound in tetrahydrofuran, dichloromethane, propan-2-,ol, propan-1-ol, ethanol and methanol. Time-Dependent Density Functional Theory (TDDFT) and B3LYP with the 6-311++G(d,p) basis set was used to model and calculate the dipole moment, polarizability and excitation energies in vacuum, cyclohexane, methanol and ethanol using computational software. In the experimental studies, four bands were observed and designated I, II, III and IV in methanol and ethanol. However three bands were observed in propan-1-ol and propan-2-ol, and two bands in dichloromethane and tetrahydrofuran. A redshift was observed in Bands I and II while a blue shift was observed for Band III as solvent polarity increases. The intensity of the bands increased with increase in solvent polarity. The dipole moment and polarizability calculated using TDDFT increased with increasing solvent polarity. This may indicate the ease of charge separation and distortion of the electron cloud of the molecule as the polarity of solvent increases. On the basis of the observations of the transition energy and wavelength with solvent polarity, the compound can be classified to have both n→p* and p→p* transitions.