Quantum Chemical Studies on Structural, Spectral and Frontier Molecular Orbital Analysis of Indometacin in Aqueous Phases

Density functional theory computations were done by using 6-31G(d) basis set in order to check out the solubility of indometacin in polar and non-polar solvents such as water, ethanol, acetone and diethyl ether, respectively. The quantum chemical parameters of indometacin in gaseous as well as in aqueous phases were calculated. The most stable structure (indometacin in water; IM-W) was found to be more stable with respect to the least stable complex (indometacin in diethyl ether; IM-D) by 3.14 Kcal/mol. The zero-point vibrational energy of indometacin in gas phase was found to be 197.731 Kcal/mol. The fundamental vibrational modes of indometacin were assignment and analyzed at B3LYP/6-31G(d) level of theory. The HOMO–LUMO analysis of indometacin showed that its HOMO is concentrated at its indole ring and LUMO is at its chlorophenyl group. The charge density distribution of indometacin was investigated through the molecular electrostatic potential map.