Preparation, Properties, and Reactivities of Unprecedented Oxo-Sulfido Nb(IV) Aqua Ions and Crystal Structure of (Me2NH2)6[Nb5(μ3-S)2(μ3-O)2(μ2-O)2(NCS)14]·3.5H2O
| Autor: | Maxim N. Sokolov, Jonas Rosager Henriksen, Svetlana G. Kozlova, Loa C. Nielsen, Inger Søtofte, Bee-Lean Ooi, Søren Birk Rasmussen |
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| Rok vydání: | 2006 |
| Předmět: | |
| Zdroj: | Inorganic Chemistry. 45:5008-5017 |
| ISSN: | 1520-510X 0020-1669 |
| DOI: | 10.1021/ic052145i |
| Popis: | By treatment of Zn-reduced ethanolic solutions of NbCl5 with HCl in the presence of sulfide followed by cation-exchange chromatography, two oxo-sulfido niobium aqua ions, the red [Nb4(μ4-S)(μ2-O)5(H2O)10]4+ and the yellow-brown [Nb5(μ3-S)2(μ3-O)2(μ2-O)2(H2O)14]8+, were isolated. Both readily form their respective thiocyanate complexes, for which the structure for the former has been previously reported. Brown crystals of (Me2NH2)6[Nb5S2O4(NCS)14]·3.5H2O (1) were isolated in the case of the latter, and the structure was determined by X-ray crystallography (space group: a = 15.4018(5) A, b = 21.1932(8) A, c = 22.0487(8) A, α = γ = 90°, β = 103.4590(10)°, and R1 = 0.0659). An unprecedented pentanuclear Nb5S2O48+ core is revealed in which short Nb−Nb distances (2.7995(8)−2.9111(8) A) are consistent with metal−metal bonding. A stopped-flow kinetic study of the 1:1 equilibration of NCS- with [Nb4(μ4-S)(μ2-O)5(H2O)10]4+ has been carried out. Equilibration rate constants are independent of [H+] in the range inve... |
| Databáze: | OpenAIRE |
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