Interactions of HNO With Metallated Porphyrins, Corroles, and Corrines

PELLEGRINO, J.; DOCTOROVICH, F.; ALVAREZ, LUCIA; MARTÍ, M. A; MORALES VÁSQUEZ, M. A.; NEUMAN, N.

The Chemistry and Biology of Nitroxyl (HNO)

Elsevier

Año: 2016; p. 193 - 205

One of the main targets of NO and HNO in biological systems is heme-proteins,thus there are a wide range of structure/reactivity studies using models, i.e., metalloporphyrins (MP), mainly of iron, but also manganese, cobalt, and ruthenium. The preferred (almost exclusively) binding mode of NO to the metal atom is through the nitrogen atom. Once bound, its character ranges (formally) from that of NO1 to that of NO2.1 In recognition of the covalent nature of the MaNO bond, Enemark and Feltham long ago proposed using the following notation for the corresponding metal nitrosyls: {MNO}n, where M designates the metal, and n stands for the total number of electrons in the d orbital of the metal ion plus those in NO π orbitals. Its relevance relies mostly on the fact that it allows rationalization of the structure (specifically the MaNaO angle, as shown in Fig. 9.1) of a wide range of different complexes.2 We will begin describing NO (as well as NO2) studies of iron porphyrins, since they are possibly the most studied systems because of their biological relevance as ?heme models.?