فهرست نشریات علمی دسترسی آزاد ایران

The structures of twenty-seven vitamin B2 conformers were optimized using two DFT methods: B3LYP and M062x functionals. Two quantum chemical approaches were used to determine the Gibbs free energy of conformers, and population ratios (PRS) were estimated using the Boltzmann distribution. . To determine valence ionization energies (IP), we used the symmetry-adapted cluster-configuration interaction (SAC-CI) general-R. The natural bond orbital approach was used to calculate orbital electron densities to characterize the ionization processes in different spectral bands.The relationship between biological activity and vitamin B2's electronic structure manifests itself in two distinct ways: its role in cellular redox processes and as a potential photosensitizer in photodynamic therapy. These findings not only provide insight into the photochemical behavior of vitamin B2 under photo-oxidation conditions, but also highlight potential applications in the design of biomolecules with enhanced receptor binding affinity. Additionally, comparisons are drawn to the closely related compound lumiflavin, for which experimental data exist, using it as a benchmark to validate our computational results. This study presents new insights into the photochemistry of vitamin B2, though the idea of linking ionization potential to biological activity is well established in previous literature and has been explored for a range of pharmacologically active substances.