TY - JOUR
T1 - Complex formation of ferric protoporphyrin IX from the reaction of hemin with ammonia and small aliphatic amines
AU - Reguera, Edilso
AU - Balmaseda, J.
AU - Fernández-Bertrán, J.
AU - Paneque, A.
AU - Yee-Madeira, H.
PY - 2004/5
Y1 - 2004/5
N2 - Complexes of Fe III protoporphyrin IX (Fe IIIPPIX) with the amido anion were obtained from the reaction of Fe IIIPPIX chloride (hemin) with ammonia and small aliphatic amines under solvent free conditions. The reaction of hemin with gaseous ammonia leads to a pentacoordinated complex at the iron site, PPIX-Fe-NH 2, plus NH 4Cl, while at the peripheral propionic acidic groups ammonium carboxylate is formed. The corresponding stoichiometry (1:4 molar ratio of hemin to ammonia) was confirmed by the adsorption isotherm. Analogous reactions and complex formation were observed with EtNH 2 and Et 2NH. These reactions were monitored using X-ray diffraction (XRD), and i.r. and Mössbauer spectroscopies. The isomer shift and quadrupole splitting values of the resulting complexes are in correspondence with the strong σ-donor character of the amido anion linked to the iron atom. For comparison, the Mössbauer parameters for hemin complexes with arginine and 2-aminoguanidine, which also have pure σ interaction with the porphyrin iron, were included and discussed.
AB - Complexes of Fe III protoporphyrin IX (Fe IIIPPIX) with the amido anion were obtained from the reaction of Fe IIIPPIX chloride (hemin) with ammonia and small aliphatic amines under solvent free conditions. The reaction of hemin with gaseous ammonia leads to a pentacoordinated complex at the iron site, PPIX-Fe-NH 2, plus NH 4Cl, while at the peripheral propionic acidic groups ammonium carboxylate is formed. The corresponding stoichiometry (1:4 molar ratio of hemin to ammonia) was confirmed by the adsorption isotherm. Analogous reactions and complex formation were observed with EtNH 2 and Et 2NH. These reactions were monitored using X-ray diffraction (XRD), and i.r. and Mössbauer spectroscopies. The isomer shift and quadrupole splitting values of the resulting complexes are in correspondence with the strong σ-donor character of the amido anion linked to the iron atom. For comparison, the Mössbauer parameters for hemin complexes with arginine and 2-aminoguanidine, which also have pure σ interaction with the porphyrin iron, were included and discussed.
UR - http://www.scopus.com/inward/record.url?scp=3543102731&partnerID=8YFLogxK
U2 - 10.1023/B:TMCH.0000027455.71173.d3
DO - 10.1023/B:TMCH.0000027455.71173.d3
M3 - Artículo
SN - 0340-4285
VL - 29
SP - 451
EP - 456
JO - Transition Metal Chemistry
JF - Transition Metal Chemistry
IS - 4
ER -