title: Discrimination of nitroxyl and nitric oxide by water-soluble Mn(III) porphyrins.
abstract: The water-soluble manganese(III) meso-tetrakis (N-ethylpyridinium-2-yl) porphyrin (Mn(III)TEPyP) and manganese(III) meso-(tetrakis(4-sulfonato-phenyl)) porphyrinate (Mn(III)TPPS) are able to chemically distinguish between HNO and NO donors, reacting with the former in a fast, efficient, and selective manner with concomitant formation of the {MnNO}(7) complex (k(on(HNO)) approximately equal to 10(5) M(-1) s(-1)), while they are inert or react very slowly with NO donors. DFT calculations and kinetic data suggest that HNO trapping is operative at least in the case of Mn(III)TPPS, while catalytic decomposition of the HNO donors (sodium trioxodinitrate and toluene sulfohydroxamic acid) seems to be the main pathway for Mn(III)TEPyP. In the presence of oxygen, the product Mn(II)TEPyP(NO) oxidizes back to Mn(III)TEPyP, making it possible to process large ratios of nitroxyl donor with small amounts of porphyrin.
authors.affiliation: Departamento de Química Inorgánica, Analítica y Qca. Física/INQUIMAE-CONICET, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Ciudad Universitaria, Pab II, P. 3, Buenos Aires (C1428EHA), Argentina.
authors.forename: Marcelo A
authors.initials: MA
authors.lastname: Martí
authors.forename: Sara E
authors.initials: SE
authors.lastname: Bari
authors.forename: Darío A
authors.initials: DA
authors.lastname: Estrin
authors.forename: Fabio
authors.initials: F
authors.lastname: Doctorovich
mesh_terms: D000693:Anaerobiosis; D006877:Hydroxamic Acids / Q000737:chemistry; D007700:Kinetics; D008345:Manganese / Q000737:chemistry*; D008665:Metalloporphyrins / Q000737:chemistry*; D009569:Nitric Oxide / Q000737:chemistry*; D020030:Nitric Oxide Donors / Q000737:chemistry; D009573:Nitrites / Q000737:chemistry; D009589:Nitrogen Oxides / Q000737:chemistry*; D010084:Oxidation-Reduction; D011166:Porphyrins / Q000737:chemistry*; D012995:Solubility; D014867:Water / Q000737:chemistry
chemical_list: D006877:Hydroxamic Acids; D008665:Metalloporphyrins; D020030:Nitric Oxide Donors; D009573:Nitrites; D009589:Nitrogen Oxides; D011166:Porphyrins; C431023:manganese (III) meso-tetrakis(N-ethylpyridinium-2-yl)porphyrin; D014867:Water; C021229:oxyhyponitrite; D009569:Nitric Oxide; C016136:tetraphenylporphine sulfonate; D008345:Manganese; C039900:nitroxyl