Study of Supramolecular Antioxidant-Photosensitizer Dyads for Drug Delivery Using Quantum Chemical Descriptors:HOMO-LUMO, Dipole Moment, and Binding Energy

The research uses Density Functional Theory to study the molecular and electronic behavior of new supramolecular dyads that link a flavonoid to C₆₀ fullerene and allicin therapeutic agents. The research evaluates their dual functionality for photodynamic therapy and antioxidant pharmacology through electronic analysis of their operational mechanisms. The optimization of geometries shows that both dyads maintain stable molecular structures. The fullerene–flavonoid dyad achieves stability through powerful pi–pi stacking bonds, yet the allicin–flavonoid complex forms through hydrogen bonds and van der Waals forces, which produce substantial negative binding energies that prove thermodynamic stability.

We used electronic structure parameters to study the charge transfer behavior of the system. The HOMO–LUMO energy gap of the fullerene–flavonoid dyad decreased substantially from the flavonoid alone, which indicates improved electronic polarizability and reduced photoexcitation energy needs for photosensitization applications. The molecular electrostatic potential maps on the flavonoid and fullerene cage were calculated to figure out how the photoinduced electron transfer from the flavonoid to the acceptor for reactive oxygen species production works. The allicin–flavonoid dyad shows a reduced HOMO–LUMO gap with orbital distribution across the entire complex, which indicates a cooperative effect that boosts electron donation for better radical scavenging.

The allicin–flavonoid complex exhibits a higher dipole moment than the fullerene-based dyad, which indicates better solubility in biological fluids with polar characteristics. The study shows that the allicin–flavonoid dyad acts as a strong synergistic antioxidant. Also, the fullerene–flavonoid structure can be a potential photosensitizer candidate according to quantum chemical descriptor analysis for drug development.