Exceptionally rapid CO release from a manganese(I) tricarbonyl complex derived from bis(4-chloro-phenylimino)acenaphthene upon exposure to visible light.

Two manganese(i) carbonyl complexes derived from α,α'-diimine ligands with extended conjugated framework namely [MnBr(CO)3(BIAN)] () and [MnBr(CO)3(MIAN)] (), have been synthesized and structurally characterized. Unlike the previously reported photoactive CO-releasing molecules (photoCORMs), these two complexes exhibit unusually high sensitivity toward low power (0.3-10 mW) visible light (λ ≥ 520 nm) even in the solid state and rapidly release carbon monoxide (CO) upon illumination. The role of the ligand frames in such activity has been examined with the help of theoretical calculations. Application of these photoCORMs in delivering high fluxes of CO to biological targets is anticipated.