INQUIMAE   12526
INSTITUTO DE QUIMICA, FISICA DE LOS MATERIALES, MEDIOAMBIENTE Y ENERGIA
Unidad Ejecutora - UE
artículos
Título:
Stabilization and detection of nitroxyl by iron and cobalt porphyrins in solution and on surfaces
Autor/es:
DOCTOROVICH, FABIO; BIKIEL, D.; PELLEGRINO, JUAN; SUÁREZ, S.; MARTÍ, M
Revista:
JOURNAL OF PORPHYRINS AND PHTHALOCYANINES
Editorial:
WORLD SCI PUBL CO INC
Referencias:
Año: 2010 vol. 14 p. 1012 - 1012
ISSN:
1088-4246
Resumen:
Nitroxyl (HNO/NO‑) is a small short-lived molecule that has been suggested to be producedby nitric oxide (NO) synthases under certain conditions. As for NO, biologically relevant targets of HNO are mainly heme-proteins and therefore, it has been difficult to discriminate the physio-pathological role of each molecule conclusively. Therefore, accurate discrimination between them is still an unresolved matter. On the other hand, there is only scarce information about nitroxyl-metalloporphyrin complexes. Hence, there is growing interest in obtaining and characterizing stable heme model nitroxyl complexes. In this review we show how HNO and NO can be discriminated electrochemically by a Co porphyrinattached to a gold surface, and how nitroxyl can be stabilized by coordination to an electron-poor Fe porphyrin. The Co porphyrin with four anchors, cobalt(II)-5,10,15,20-tetrakis[3-(p-acetylthio-propoxy) phenyl]porphyrin [Co(P)] was covalently attached to gold electrodes, and its reactions with NO and HNO donors were studied electrochemically. By fixing the potential to values that oxidize CoIII(P)NO‑, HNO can be selectively detected by amperometric techniques. On the other hand, the one-electron chemical reduction of FeII(TFPPBr8)NO (TFPPBr8 = 2,3,7,8,12,13,17,18-octa-β-bromo-5,10,15,20-[tetrakis-(pentafluorophenyl)]porphyrin) with cobaltocene yields the significantly stable {FeNO}8 nitroxyl anion complex, [Co(C5H5)2]+[Fe(TFPPBr8)NO]‑, which was isolated and characterized by several spectroscopies and DFT calculations. This species is intermediate between FeIINO‑ and FeINO, which is contrasted with the predominant FeIINO‑ character of known non-heme {FeNO}8 complexes.