Fast Nitroxyl Trapping by Ferric Porphyrins

SARA E. BARI,; MARCELO A. MARTÍ; VALENTÍN T. AMOREBIETA; DARÍO A. ESTRIN; FABIO DOCTOROVICH

JOURNAL OF THE AMERICAN CHEMICAL SOCIETY

ACS publications

Año: 2003 vol. 125 p. 15272 - 15273

0002-7863

Iron(II) porphyrin nitrosyl complexes are obtained in high yields from the reaction of iron(III) porphyrins with the nitroxyl donors sodium trioxodinitrate and toluensulfohydroxamic acid. The reaction was found to proceed both in organic solvents and in aqueous media from iron(III) (meso-tetraphenyl) porphyrinate ([FeIII(TPP)]+) and iron(III) meso-tetrakis (4-sulfonatophenyl) porphyrinate ([FeIII(TPPS)]3-) or iron(III) protoporphyrin IX, respectively. The kinetic rate constant for the reaction of ([FeIII(TPPS)]3-) with sodium trioxodinitrate (kon) was estimated to be 1.00 ± 0.04 × 107 M-1 s-1. As well as resulting in a versatile method for obtaining ferrous nitrosyl porphyrins, the reaction points at ferric porphyrins as efficient nitroxyl traps and provides a tool to model nitroxyl reactivity toward hemeproteins.