Molecular Structural Study and Solvent Effects on Menthol and Carvacrol Compounds: DFT Studies

Menthol the most important ingredient in mint and carvacrol essential oil is an important essential nutrient of thyme. Carvacrol and menthol compounds are two important compounds with many medicinal properties, one of their important properties are being antioxidant, which results in the widespread use of these two. The aim of this study was to investigate the structural parameters, HOMO-LUMO energy gap, polarization, hardness, chemical potential, electron density index, and charge of two antioxidant compounds of menthol and carvacrol in the gas phase and in methanol DMSO and dichloromethane solvents. The calculations are performed using the functional density theory with the B3LYP method and using the base set of 6-311G + (d, p). According to the calculations, for menthol and carvacrol compounds the energy gap and hardness are the highest in the DMSO solvent and the lowest in the gas phasewere obtained. The presence of solvent in menthol increased chemical hardness and for carvacrol, the solvent was no significant effect on chemical hardness. A comparison of the chemical potential of menthol and carvacrol compounds showed that the reactivity of carvacrol more than menthol is due to the low chemical potential of carvacrol.The softness and electronaphinity  for menthol in the gas phase were the highest and in carvacrol was not observed a lot of difference in gas and solvent phase.