Photoresponsive Ferrocene‐ Augmented Iridium Polypyridyl Complex as an Oxidase Mimic for Selective Glutathione Sensing: Implications for Cancer Diagnostics and Therapy

Abstract The enzyme‐mimic activity of a well‐defined structurally characterized organometallic complex, [Ir(ppy)₂(fcbpy)]PF₆( 1 ; ppy = 2‐phenylpyridine; fcbpy = 4‐ferrocenyl‐2,2′‐bipyridine), a bimetallic iridium‐polypyridyl complex is investigated under light irradiation for the first time. This complex exhibits an extended excited‐state lifetime of 592 ns due to bimetallic synergy, and possess oxidase‐mimic activity in the presence of light. Leveraging this light‐activated oxidase‐mimic activity, a simple colorimetric assay is developed that successfully differentiates cancerous cells from normal cells, based on elevated glutathione (GSH) levels. Moreover, in cell viability studies, treatment with 1.25 mg L ⁻¹ of [Ir(ppy)₂(fcbpy)]PF₆ resulted in only 32.25% viability in a cancer cell line (A549) compared to the untreated control, highlighting its potent anticancer potential. Importantly, noncancerous cells (BEAS‐2B) maintain ≈72% viability at up to 10 mg L ⁻¹ of catalyst concentration, indicating selective cytotoxicity toward cancer cells. This study establishes [Ir(ppy)₂(fcbpy)]PF₆ as a promising candidate for both diagnostic and therapeutic applications in cancer, introducing a novel class of organometallic complexes with significant potential in bioassay development and targeted cancer treatment.