Investigation of light-triggered carbon monoxide release from two manganese photoCORMs by IR, UV-Vis and EPR spectroscopy

► Photolytic CO release from [Mn(CO)3] complexes was studied by UV-Vis, IR and EPR. ► IR indicates that CO loss occurs stepwise via intermediate dicarbonyl complexes. ► The process is accompanied by Mn oxidation as clearly detected by EPR.