Computational Insights into Structural, Optoelectronic and Charge Transfer Properties of Monocarbonyl Curcumin Derivatives for Biomedical and Photonic Applications

Curcumin and its derivatives have garnered considerable attention due to their multifunctional applications in medicinal chemistry and material sciences. However, their inherent limitations, such as poor photostability and solubility, necessitate structural modifications to enhance their optoelectronic properties. The molecular properties of four monocarbonyl curcumin derivatives (CB1–CB4) were investigated using density functional theory (DFT) in both gas and solvent phases. Frontier molecular orbital (FMO) analysis identified CB1 as the most reactive derivative, characterized by the smallest energy gap and high softness values. Ionization potential (IP) analysis revealed that CB3 has a high IP, though slightly lower than R, suggesting strong hole-transport characteristics. Density of states (TDOS, PDOS, OPDOS) analysis demonstrated significant bonding-antibonding interactions, correlating with strong electronic transitions. Furthermore, time-dependent DFT (TD-DFT) calculations revealed bathochromic and hyperchromic shifts, with CB2 and CB4 facilitating charge transfer transitions. The extended radiative lifetimes (3–6 ns) for CB2 and CB4 suggest their suitability for photonic and solar cell applications. The natural bond orbital (NBO) analysis confirmed charge delocalization, while natural transition orbitals (NTOs) highlighted key excitonic transitions of the studied compounds. Additionally, nonlinear optical (NLO) analysis indicated significant first-order hyperpolarizability, particularly in CB1 and CB3, reinforcing their potential for advanced optoelectronic and photonic applications.