Manganese-quinizarin-pyrazinecarboxylic acid mixed-ligand complex in aprotic media. Formation of a manganese(III)-semiquinone binuclear species

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dc.contributor.authorBodini, ME
dc.contributor.authordel Valle, MA
dc.contributor.authorCopia, G
dc.contributor.authorJara, F
dc.date.accessioned2024-01-10T13:50:14Z
dc.date.available2024-01-10T13:50:14Z
dc.date.issued1999
dc.description.abstractThe monoanion of pyrazincarboxylic acid (PcA(-)), the dianion of quinizarine (Qz(=)) and manganese(II) yield a soluble deep-blue complex in dimethylsulphoxide whose Mn-II:Qz(=):PcA(-) stoichiometry has been established as 1:1:1. This mixed-ligand complex is oxidized in two steps, each involving one equivalent of charge per complex present, as indicated by controlled-potential electrolyses done at +0.30 V versus s.c.e. and +0.50 V versus s.c.e.. The association between the metal ion and the ligands prevail and the oxidations finally produce a dark-red complex which possesses the same stoichiometry as the original deep-blue species. In the latter the metal ion is present in oxidation state +3 with the quinizarine dianion as the corresponding semiquinone of the oxidized quinizarine. The monoanion of pyrazincarboxylic acid remains unchanged. Controlled-potential electrolysis at -0.20 V versus s.c.e. of a solution of the mixed-ligand complex indicates that it is binuclear, generating a Mn-II-Mn-III mixed-valence species. The latter is, in turn, reduced at -1.60 V versus s.c.e. producing probably a mononuclear of manganese(II) species. If manganese(II) is combined with the semiquinone of quinizarine the metal ion exhibits the magnetic characteristic of manganese(III) and the semiquinone is reduced to the quinizarine dianion, indicating that the mixed-ligand formed exhibits intramolecular charge-transfer. This is a good example of a binuclear species accumulating four oxidation equivalents after oxidation of both metal centers and the quinizarine ligands.
dc.fechaingreso.objetodigital2024-05-02
dc.format.extent4 páginas
dc.fuente.origenWOS
dc.identifier.doi10.1023/A:1017164226925
dc.identifier.issn0340-4285
dc.identifier.urihttps://doi.org/10.1023/A:1017164226925
dc.identifier.urihttps://repositorio.uc.cl/handle/11534/79515
dc.identifier.wosidWOS:000082568500021
dc.information.autorucQuímica;Bodini M;S/I;99293
dc.information.autorucQuímica;Del Valle M;S/I;54928
dc.issue.numero4
dc.language.isoen
dc.nota.accesocontenido parcial
dc.pagina.final477
dc.pagina.inicio474
dc.publisherKLUWER ACADEMIC PUBL
dc.revistaTRANSITION METAL CHEMISTRY
dc.rightsacceso restringido
dc.subjectOXYGEN-EVOLVING COMPLEX
dc.subjectWATER-OXIDIZING ENZYME
dc.subjectPHOTOSYSTEM-II
dc.subjectCHEMISTRY
dc.subjectDIMETHYLSULFOXIDE
dc.subjectEVOLUTION
dc.subjectCENTERS
dc.titleManganese-quinizarin-pyrazinecarboxylic acid mixed-ligand complex in aprotic media. Formation of a manganese(III)-semiquinone binuclear species
dc.typeartículo
dc.volumen24
sipa.codpersvinculados99293
sipa.codpersvinculados54928
sipa.indexWOS
sipa.indexScopus
sipa.trazabilidadCarga SIPA;09-01-2024
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