Receptor-Mediated and Hydrolytic Denitrosylation of Dinitrosyl Iron Complexes to Yield Amorphous FeO and Its Photoinduced Transformation into Crystalline Fe@FeO Nanoparticles.

In this study, denitrosylation of amine-bound {Fe(NO)} [(2-A)Fe(NO)] () was explored to occur through (a) receptor-mediated transfer of ·NO/[NO] to [Mn(TPP)(Cl)] and (b) a hydrolytic process leading to the liberation of ·NO together with NO. In the presence of the bifunctional ·NO/[NO]-receptor [Mn(TPP)(Cl)] (TPP = 5,10,15,20-tetraphenyl-21,23-porphine), acts as a dual ·NO/[NO] delivery reagent for the conversion of [Mn(TPP)(Cl)] into [Mn(TPP)(NO)] and [Mn(TPP)(NO)]. Alternatively, incubation of in an acetonitrile solution containing 5% deaerated water resulted in its hydrolytic transformation into amorphous FeO particles () accompanied by the release of ·NO (∼75%), NO (∼10%), and nitrite (∼6%). Upon irradiation of in the presence of the photosensitizer Eosin Y and the sacrificial reductant TEA, the formation of cubic and crystalline Fe@FeO core-shell composite carbonaceous material () was characterized by high-resolution X-ray diffraction (HRXRD), field emission scanning electron microscopy (FESEM), X-ray photoelectron spectroscopy (XPS), X-ray absorption near-edge spectroscopy (XANES), and extended X-ray absorption fine structure (EXAFS). Based on the mechanisms described above, the hydrolytic transformation of into occurred, followed by the photoinduced structural rearrangement of , amorphous FeO particles, into , the cubic and crystalline Fe@FeO core-shell composite carbonaceous material.