A Luminescent Manganese PhotoCORM for CO Delivery to Cellular Targets under the Control of Visible Light

A photoactive manganese carbonyl complex derived from dansylimidazole (Imdansyl), namely, [Mn(Imdansyl)(CO) 3 (phen)](CF 3 SO 3 ) ( 1 ), has been synthesized and structurally characterized. This is the first luminescent manganese carbonyl-based photoCORM reported in the literature. This complex exhibits CO release under the exclusive control of low-power broadband visible light. The corresponding rhenium carbonyl complex, namely, [Re(Imdansyl)(CO) 3 (phen)](CF 3 SO 3 ) ( 2 ), has also been reported, which is luminescent but sensitive only to UV-B (λ<315 nm) light. The entry of the manganese photoCORM into the human colorectal adenocarcinoma cells (HT-29) has been demonstrated with the aid of fluorescence microscopy. Irradiation of the photoCORM-loaded cancer cells to visible light leads to a dose-dependent apoptotic cell death.