Ítem
Ministerio de Ciencia e Innovación (Espanya)
Ministerio de Educación y Ciencia (Espanya) |
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Ponec, Robert
Ramos Cordoba, Eloy Salvador Sedano, Pedro |
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7 març 2013 | |
The electronic structure of the trinuclear symmetric complex [(tmedaCu)3S2 ]3+, whose Cu3S 2 core represents a model of the active site of metalloenzymes involved in biological processes, has been in recent years the subject of vigorous debate. The complex exists as an open-shell triplet, and discussions concerned the question whether there is a direct S-S bond in the [Cu 3S2]3+ core, whose answer is closely related to the problem of the formal oxidation state of Cu atoms. In order to contribute to the elucidation of the serious differences in the conclusions of earlier studies, we report in this study the detailed comprehensive analysis of the electronic structure of the [Cu3S2]3+ core using the methodologies that are specifically designed to address three particular aspects of the bonding in the core of the above complex, namely, the presence and/or absence of direct S-S bond, the existence and the nature of spin-spin interactions among the atoms in the core, and the formal oxidation state of Cu atoms in the core. Using such a combined approach, it was possible to conclude that the picture of bonding consistently indicates the existence of a weak direct two-center-three-electron (2c-3e) S-S bond, but at the same time, the observed lack of any significant local spin in the core of the complex is at odds with the suggested existence of antiferromagnetic coupling among the Cu and S atoms, so that the peculiarities of the bonding in the complex seem to be due to extensive delocalization of the unpaired spin in the [Cu 3S2]3+ core. Finally, a scrutiny of the effective atomic hybrids and their occupations points to a predominant formal CuII oxidation state, with a weak contribution of partial Cu I character induced mainly by the partial flow of electrons from S to Cu atoms and high delocalization of the unpaired spin in the [Cu 3S2]3+ core This study was supported by the grant of the Grant Agency of the Czech Republic (grant No: 203/09/0118). This support is gratefully acknowledged by R.P. P.S. and E.RC. also acknowledge financial support from the Spanish Ministerio de Ciencia y Tecnologia (project No. MAT2008-04834 and CTQ2011-23441/BQU) and from the Spanish FPU program (Grant No. AP2008-01231) |
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application/pdf | |
http://hdl.handle.net/10256/11531 | |
eng | |
American Chemical Society (ACS) | |
info:eu-repo/semantics/altIdentifier/doi/10.1021/jp309295r info:eu-repo/semantics/altIdentifier/issn/1089-5639 info:eu-repo/semantics/altIdentifier/eissn/1520-5215 info:eu-repo/grantAgreement/MICINN//MAT2008-04834/ES/PEPTIDOS E INTERACCIONES MOLECULARS: ESTRATEGIAS DE CALCULO Y SOLIDEZ COMPUTACIONAL/ |
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info:eu-repo/grantAgreement/MICINN//CTQ2011-23441/ES/NUEVOS ENFOQUES PARA EL ESTUDIO COMPUTACIONAL DE BIOMOLECULAS, INTERACCIONES DE ESPIN EN AGREGADOS METALICOS Y SISTEMAS MOLECULARES DE ALMACENAMIENTO DE HIDROGENO/ | |
Tots els drets reservats | |
Complexos metàl·lics de transició
Transition metal complexes Enllaços químics Chemical bonds Funcions d’ona Wave functions València (Química teòrica) Valence (Theoretical chemistry) |
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Bonding quandary in the [Cu3S2]3+ core: Insights from the analysis of domain averaged fermi holes and the local spin | |
info:eu-repo/semantics/article | |
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