Theoretical prediction of chloroform, ethanol, water and DMSO effects on electronic characteristics of Capecitabine different conformers as an anticancer chemotherapy drug

In this study, the solvent effects on the structures and strength of intramolecular hydrogen bonds (HBs) of capecitabine conformers were investigated using density functional theory. The achieved results show the hydrogen bonds strongly affect the stability order of conformers so that IHB strength among the solvents is increased as: chloroform > ethanol > water > DMSO. Also, A1 and A3 conformers are stabilized more than other conformers in gas phase and solution phase respectively. This stability with increase of dielectric constant is lessened. The natural bond orbital and the Quantum Theory of “Atoms in Molecules” (QTAIM) of Bader were also applied to achieve more details about the nature of intermolecular and HB interactions. Finally, electronic descriptors such as energy gap, hardness, softness and chemical potential were investigated.