Probing the redox-conversion of Co(II)-disulfide to Co(III)-thiolate complexes
| Autor: | Christian Marvelous, Lucas de Azevedo Santos, Maxime A. Siegler, Célia Fonseca Guerra, Elisabeth Bouwman |
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| Přispěvatelé: | Theoretical Chemistry, AIMMS |
| Jazyk: | angličtina |
| Rok vydání: | 2022 |
| Předmět: | |
| Zdroj: | Marvelous, C, de Azevedo Santos, L, Siegler, M A, Fonseca Guerra, C & Bouwman, E 2022, ' Probing the redox-conversion of Co(II)-disulfide to Co(III)-thiolate complexes : the effect of ligand-field strength ', Dalton transactions (Cambridge, England : 2003), vol. 51, no. 20, pp. 8046-8055 . https://doi.org/10.1039/d2dt00356b Dalton Transactions, 51(20), 8046-8055 Dalton transactions (Cambridge, England : 2003), 51(20), 8046-8055. Royal Society of Chemistry |
| ISSN: | 1477-9234 8046-8055 |
| Popis: | The redox-conversion reaction of cobalt(II)-disulfide to cobalt(III)-thiolate complexes triggered by addition of the bidentate ligand 2,2'-bipyridine has been investigated. Reaction of the cobalt(II)-disulfide complex [Co2(L1SSL1)(X)4] (L1SSL1 = di-2-(bis(2-pyridylmethyl)amino)-ethyldisulfide; X = Cl or Br) [1X] with 2,2'-bipyridine (bpy) resulted in the formation of two different products, namely the cobalt(III)-thiolate complex [Co(L1S)(bpy)]X2 and the unexpected side product [Co2(L1SSL1)(bpy)2(X)2]X2. Crystals of [Co2(L1SSL1)(bpy)2(Cl)2](BPh4)2 [2Cl](BPh4)2 obtained after anion exchange showed the cobalt(II) ions to be in octahedral geometries with the nitrogen donors of the disulfide ligand arranged in a facial conformation and the chloride ion trans to the tertiary amine nitrogen. Remarkably, this side product cannot be converted to the cobalt(III)-thiolate compound [Co(L1S)(bpy)](SbF6)2 [3](SbF6)2 by removal of the chloride ion with use of a silver salt, as this causes scrambling of the ligands, resulting in the formation of [Co(bpy)3]n+. [Co(L1S)(bpy)](SbF6)2 was obtained in a pure form by addition of bpy to a solution in acetonitrile of the compound [Co(L1S)(MeCN)2]2+ [4]2+. Addition of NEt4Cl to [3](SbF6)2 regenerates the cobalt(II)-disulfide complex [1Cl] as confirmed spectroscopically. DFT studies revealed that the conversion from [1Cl] to [3]2+ most likely occurs via the hypothetical intermediate species [2Cl]2+mer, in which the nitrogen atoms of the disulfide ligand are arranged in a meridional conformation. Interestingly, the estimated d-orbital splitting energy of [3]2+ is lower than that of [4]2+, indicating that the ligand-field strength of bpy is lower than anticipated, which hampers clean conversion in the redox-conversion reaction. This study shows that the redox-conversion reaction between cobalt(II)-disulfide and cobalt(III)-thiolate complexes is intricate rather than straightforward. |
| Databáze: | OpenAIRE |
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