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001-es BibID:	BIBFORM032036
Első szerző:	Szabó Orsolya (vegyész)
Cím:	Characterization of Mn(II) and Mn(III) binding capability of natural siderophores desferrioxamine B and desferricoprogen as well as model hydroxamic acids / Orsolya Szabó, Etelka Farkas
Dátum:	2011
ISSN:	0020-1693
Megjegyzések:	Complexes formed between Mn(II) ion and acetohydroxamic acid (HAha), benzohydroxamic acid (HBha),N-methyl-acetohydroxamic acid (HMeAha), DFB model dihydroxamic acids (H2(3,4-DIHA), H2(3,3-DIHA),H2(2,5-DIHA), H2(2,5-H,H-DIHA), H2(2,4-DIHA), H2(2,3-DIHA)) and two trihydroxamate based naturalsiderophores, desferrioxamine B (H4DFB) and desferricoprogen (H3DFC) have been investigated underanaerobic condition (and some of them also under aerobic condition). The pH-potentiometric resultsshowed the formation of well-defined complexes with moderate stability. Monohydroxamic acids not,but all of the dihydroxamic acids and trihydroxamic acids were able to hinder the hydrolysis of the metalion up to pH ca. 11. Maximum three hydroxamates were found to coordinate to the Mn(II) ion, but presenceof water molecule in the inner-sphere was also indicated by the corresponding relaxivity valueseven in the tris-chelated complexes. Moreover, prototropic exchange processes were found to increasethe relaxation rate of the solvent water proton over the value of [Mnaqua]2+ in the protonated Mn(II)?siderophore complexes at physiological pH. The much higher stability of Mn(III)?hydroxamate(especially tris-chelated) complexes compared to the corresponding Mn(II)-containing species resultsin a significantly decreased formal potential compared to the Mn(III)aqua/Mn(II)aqua system. As a result,air oxygen becomes an oxidizing agent for these manganese(II)?hydroxamate complexes above pH 7.5.The oxidation processes, followed by UV?Vis spectrophotometry, were found to be stoichiometric onlyin the case of the tris-chelated complexes of siderophores, which predominate above pH 9. ESI-MSprovided support about the stoichiometry and cyclic-voltammetry was used to determine the stabilityconstants for the tris-chelated complexes, [Mn(HDFB)]+ and [MnDFC].OTKA-NKTH CK77586
Tárgyszavak:	Természettudományok Kémiai tudományok idegen nyelvű folyóiratközlemény külföldi lapban folyóiratcikk Hydroxamic acids Siderophores Manganese(II)/(III) complexes Solution equilibria Redox behaviour Relaxivity
Megjelenés:	Inorganica Chimica Acta. - 376 : 1 (2011), p. 500-508. -
További szerzők:	Farkas Etelka (1948-) (vegyész)
Internet cím:	Szerző által megadott URL DOI Intézményi repozitóriumban (DEA) tárolt változat
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