The binary and ternary systems formed by (VO)-O-IV and Cu-II ions with ligands (L) based on the pyridine ring (1,10-phenanthroline (phen), 2,2'-bipyridine (bpy), 2,2': 6',2 ''-terpyridine (terpy), 2,2'-bipyrimidine (bpm) and 2,3-bis(2-pyridyl)pyrazine (bpp)) were studied, combining spectroscopic (EPR and UV-vis), pH-potentiometric and computational (DFT calculations) methods. In the systems with (VO)-O-IV, the formation of mono-chelated complexes with equatorial-equatorial and equatorial-axial (phen, bpy, bpm and bpp) or equatorial-equatorial-equatorial and equatorial-axial-equatorial coordination (terpy) and bis-chelated species with cis-octahedral geometry, with a water or a hydroxido ion in the fourth equatorial position, is demonstrated. Phen, bpy, bpm and bpp form also a dinuclear [(VO)(2)L-2(H2O)(2)(OH)(2)](2+) complex with an anti-coplanar arrangement of the two (VO)-O-IV ions and a ferromagnetic coupling between the metal ions. Due to the low basicity of the nitrogen donors, the potentially tetradentate 2,2'-bipyrimidine and 2,3-bis(2-pyridyl)pyrazine behave like simple bidentate ligands, and in the ternary systems with 2,2'-bipyridine the expected dinuclear species, in which the former ligands would act as a bridge between the two metal ions using all four nitrogen donors, are not formed. The interaction of phen and Cu-II-phen complexes with human serum albumin (HSA) was also studied at pH 7.4 by circular dichroism and EPR spectroscopy, the formation of several HSA-Cu-II-phen containing species being confirmed and their binding constants determined.

VIVO and CuII complexation by ligands based on pyridine nitrogen donors / D., Sanna; P., Buglyó; A. I., Tomaz; J., Costa Pessoa; S., Borović; G., Micera; Garribba, Eugenio. - In: DALTON TRANSACTIONS. - ISSN 1477-9226. - 41:(2012), pp. 12824-12838. [10.1039/c2dt31109g]

VIVO and CuII complexation by ligands based on pyridine nitrogen donors

GARRIBBA, Eugenio
2012-01-01

Abstract

The binary and ternary systems formed by (VO)-O-IV and Cu-II ions with ligands (L) based on the pyridine ring (1,10-phenanthroline (phen), 2,2'-bipyridine (bpy), 2,2': 6',2 ''-terpyridine (terpy), 2,2'-bipyrimidine (bpm) and 2,3-bis(2-pyridyl)pyrazine (bpp)) were studied, combining spectroscopic (EPR and UV-vis), pH-potentiometric and computational (DFT calculations) methods. In the systems with (VO)-O-IV, the formation of mono-chelated complexes with equatorial-equatorial and equatorial-axial (phen, bpy, bpm and bpp) or equatorial-equatorial-equatorial and equatorial-axial-equatorial coordination (terpy) and bis-chelated species with cis-octahedral geometry, with a water or a hydroxido ion in the fourth equatorial position, is demonstrated. Phen, bpy, bpm and bpp form also a dinuclear [(VO)(2)L-2(H2O)(2)(OH)(2)](2+) complex with an anti-coplanar arrangement of the two (VO)-O-IV ions and a ferromagnetic coupling between the metal ions. Due to the low basicity of the nitrogen donors, the potentially tetradentate 2,2'-bipyrimidine and 2,3-bis(2-pyridyl)pyrazine behave like simple bidentate ligands, and in the ternary systems with 2,2'-bipyridine the expected dinuclear species, in which the former ligands would act as a bridge between the two metal ions using all four nitrogen donors, are not formed. The interaction of phen and Cu-II-phen complexes with human serum albumin (HSA) was also studied at pH 7.4 by circular dichroism and EPR spectroscopy, the formation of several HSA-Cu-II-phen containing species being confirmed and their binding constants determined.
2012
VIVO and CuII complexation by ligands based on pyridine nitrogen donors / D., Sanna; P., Buglyó; A. I., Tomaz; J., Costa Pessoa; S., Borović; G., Micera; Garribba, Eugenio. - In: DALTON TRANSACTIONS. - ISSN 1477-9226. - 41:(2012), pp. 12824-12838. [10.1039/c2dt31109g]
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11388/84602
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