Mixed-valence cyano-bridged complexes containing [M(CN)6]4 (M = Fe, Ru or Os) and [Runi(edta)]~ (edta = ethylenedinitrilotetraacetate): Synthesis, spectroscopic and kinetic characterization
The mixed-valence, cyanide-bridged complexes K5[(NC)jMII-CN-RuI(edta)] (M = Fe, Ru or Os; edta = ethylenedinitrilotetraacetate) were prepared by mixing the hexacyanide species with a solution of [Ru(edta)(H 22 O)]~. The complexes were characterized by chemical analysis, IR, Raman and VIS/NIR spectro...
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1997
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Acceso en línea: | https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_03009246_v_n9_p1595_Forlano http://hdl.handle.net/20.500.12110/paper_03009246_v_n9_p1595_Forlano |
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paper:paper_03009246_v_n9_p1595_Forlano2023-06-08T15:27:35Z Mixed-valence cyano-bridged complexes containing [M(CN)6]4 (M = Fe, Ru or Os) and [Runi(edta)]~ (edta = ethylenedinitrilotetraacetate): Synthesis, spectroscopic and kinetic characterization The mixed-valence, cyanide-bridged complexes K5[(NC)jMII-CN-RuI(edta)] (M = Fe, Ru or Os; edta = ethylenedinitrilotetraacetate) were prepared by mixing the hexacyanide species with a solution of [Ru(edta)(H 22 O)]~. The complexes were characterized by chemical analysis, IR, Raman and VIS/NIR spectroscopy. They show an intense band in the 600-1000 nm region (dependent on M), associated with an intervalence (i.v.) transition from M to Ru1, as confirmed by electrochemical measurements of the redox potentials at both metal centres. The equilibrium constants for the formation of the binuclear species were similar for the three complexes, (1.5 ±0.1) x 103 dm3 mol1. These complexes were the predominant species in excess of free hexacyanide, but tri- and poly-nuclear species were obtained by increasing the concentration of [Ru(edta)(H 22 O)]~, as demonstrated through the electronic spectral shifts of the i.v. band and the redox potentials of the M couples, which were indicative of Ru(edta) co-ordination to the exposed nitrogen ends of cyanides in the precursor binuclear complexes. The kinetics of formation and dissociation of the binuclear complexes were also measured, with k, and kA showing values nearly independent of.M (ca. 10 dm3 mol1 s1 and 8 x 10~3 s1 respectively, at 25.0 °C, /= 0.1 mol dnT3), suggesting thé onset of associative mechanisms. The Hush model showed the three complexes to adopt a valence-trapped behaviour, with a moderate coupling between the metal centres. 1997 https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_03009246_v_n9_p1595_Forlano http://hdl.handle.net/20.500.12110/paper_03009246_v_n9_p1595_Forlano |
institution |
Universidad de Buenos Aires |
institution_str |
I-28 |
repository_str |
R-134 |
collection |
Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) |
description |
The mixed-valence, cyanide-bridged complexes K5[(NC)jMII-CN-RuI(edta)] (M = Fe, Ru or Os; edta = ethylenedinitrilotetraacetate) were prepared by mixing the hexacyanide species with a solution of [Ru(edta)(H 22 O)]~. The complexes were characterized by chemical analysis, IR, Raman and VIS/NIR spectroscopy. They show an intense band in the 600-1000 nm region (dependent on M), associated with an intervalence (i.v.) transition from M to Ru1, as confirmed by electrochemical measurements of the redox potentials at both metal centres. The equilibrium constants for the formation of the binuclear species were similar for the three complexes, (1.5 ±0.1) x 103 dm3 mol1. These complexes were the predominant species in excess of free hexacyanide, but tri- and poly-nuclear species were obtained by increasing the concentration of [Ru(edta)(H 22 O)]~, as demonstrated through the electronic spectral shifts of the i.v. band and the redox potentials of the M couples, which were indicative of Ru(edta) co-ordination to the exposed nitrogen ends of cyanides in the precursor binuclear complexes. The kinetics of formation and dissociation of the binuclear complexes were also measured, with k, and kA showing values nearly independent of.M (ca. 10 dm3 mol1 s1 and 8 x 10~3 s1 respectively, at 25.0 °C, /= 0.1 mol dnT3), suggesting thé onset of associative mechanisms. The Hush model showed the three complexes to adopt a valence-trapped behaviour, with a moderate coupling between the metal centres. |
title |
Mixed-valence cyano-bridged complexes containing [M(CN)6]4 (M = Fe, Ru or Os) and [Runi(edta)]~ (edta = ethylenedinitrilotetraacetate): Synthesis, spectroscopic and kinetic characterization |
spellingShingle |
Mixed-valence cyano-bridged complexes containing [M(CN)6]4 (M = Fe, Ru or Os) and [Runi(edta)]~ (edta = ethylenedinitrilotetraacetate): Synthesis, spectroscopic and kinetic characterization |
title_short |
Mixed-valence cyano-bridged complexes containing [M(CN)6]4 (M = Fe, Ru or Os) and [Runi(edta)]~ (edta = ethylenedinitrilotetraacetate): Synthesis, spectroscopic and kinetic characterization |
title_full |
Mixed-valence cyano-bridged complexes containing [M(CN)6]4 (M = Fe, Ru or Os) and [Runi(edta)]~ (edta = ethylenedinitrilotetraacetate): Synthesis, spectroscopic and kinetic characterization |
title_fullStr |
Mixed-valence cyano-bridged complexes containing [M(CN)6]4 (M = Fe, Ru or Os) and [Runi(edta)]~ (edta = ethylenedinitrilotetraacetate): Synthesis, spectroscopic and kinetic characterization |
title_full_unstemmed |
Mixed-valence cyano-bridged complexes containing [M(CN)6]4 (M = Fe, Ru or Os) and [Runi(edta)]~ (edta = ethylenedinitrilotetraacetate): Synthesis, spectroscopic and kinetic characterization |
title_sort |
mixed-valence cyano-bridged complexes containing [m(cn)6]4 (m = fe, ru or os) and [runi(edta)]~ (edta = ethylenedinitrilotetraacetate): synthesis, spectroscopic and kinetic characterization |
publishDate |
1997 |
url |
https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_03009246_v_n9_p1595_Forlano http://hdl.handle.net/20.500.12110/paper_03009246_v_n9_p1595_Forlano |
_version_ |
1768542362539130880 |