Environment and solute-solvent interaction effects on photo-physical behaviors of Folic acid and Folinic acid drugs

• P-Aminobenzamide and pterin have dominant role in photo-physical behaviors of drug molecules.
• Spectral behavior of drugs depend strongly on solute-solvent specific and nonspecific interactions.
• The dipole moments changes show that intramolecular charge transfer can occur during the excitation.
• The results about molecular interactions can indicate the behaviors of drug molecules in body system.

In this paper, spectral properties of Folic acid and Folinic acid as widely used drugs in the treatment of some diseases have been studied in various environments with different polarity. Our results show that the absorption, emission and stokes shifts of solute molecules depend strongly on molecular surrounding characteristics, solute-solvent interactions and, different active groups in their chemical structures. In order to investigate the contribution of specific and nonspecific interactions on various properties of drug samples, the linear solvation energy relationships concept is used. Moreover, the calculated dipole moments by means of solvatochromic method show that the high values of dipole moments in excited state are due to local intramolecular charge transfer. Furthermore, the obtained results about molecular interactions can be extended to biological systems and can indicate completely the behaviors of Folic acid and Folinic acid in polar solvents such as water in body system.