Can a Nitrosyl of a Mn(II)-Porphyrin Complex Release Nitroxyl/HNO?

In general, the nitrosyl complexes of Mn(II)-porphyrinate having the {Mn(NO)} configuration are not considered as HNO or nitroxyl (NO) donors because of [Mn-NO] nature. A nitrosyl complex of Mn(II)-porphyrin, [Mn(TMPP)(NO)], [TMPPH = 5,10,15,20-tetrakis-4-methoxyphenylporphyrin], is shown to release HNO in the presence of HBF. It is evidenced from the characteristic reaction of HNO with triphenylphosphine and isolation of the [(TMPP)Mn(HO)](BF), . This is attributed to the fact that H from HBF polarizes the NO group whereas the BF interacts with metal ion to stabilize the Mn(III) form. These two effects cooperatively result in the release of HNO from complex . In addition, complex behaves as a nitroxyl (NO) donor in the presence of [Fe(dtc)] (dtc = diethyldithiocarbamate anion) and [Fe(TPP)(Cl)] (TPP = 5,10,15,20-tetraphenylporphyrinate) to result in [Fe(dtc)(NO)] and [Fe(TPP)(NO)], respectively.