Photophysical Properties of a Chiral Iridium-Based Photosensitizer as an Efficient Photodynamic Therapy Agent: A Theoretical Investigation

This study employs time-dependent density functional theory to explore the photophysical properties of a chiral iridium(III) complex designed as a photosensitizer for photodynamic therapy. Key properties analyzed include one-photon absorption energies, singlet–triplet energy gaps, spin–orbit coupling constants, and intersystem crossing rate constants. The potential for operation in a Type I PDT mechanism was assessed through ionization potential and electron affinity calculations. The results demonstrate that the complex is a promising PDT candidate, primarily operating in a Type II mechanism, while offering conditional viability for Type I photoreactivity under specific electronic and environmental conditions.