Synthesis, Structures, and CO Releasing Properties of two Tricarbonyl Manganese(I) Complexes

[MnBr(CO)5] reacts with one equivalent each of 1, 3, 5-triaza-7-phosphaadamantane (PTA) and sodium diethyldithiocarbamate to afford the yellow MnI complex fac-[Mn(S2CNEt2)(PTA)(CO)3]. Similarly, the same MnI precursor reacts with the sodium salt of L-histidine to give the tricarbonyl manganese(I) complex fac-[Mn(his)(CO)3] in good yield as a yellow solid. Both compounds were spectroscopically and structurally characterised. The histidinato complex is soluble in water and its aqueous solutions are stable for more than 24 h. The CO releasing properties of the histidinato complex were studied with the myoglobin assay and establish this compound as a novel PhotoCORM, which liberates one of the three carbonyl ligands upon irradiation.