New intermediate-spin chloroiron(III) complex with a mixed nitrogen– sulfur co-ordination sphere ‡
| Autor: | Daniel Varech, Isabelle Artaud, Daniel Mansuy, Jean-Pierre Tuchagues, Marie-Aude Kopf |
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| Rok vydání: | 1998 |
| Předmět: | |
| Zdroj: | Journal of the Chemical Society, Dalton Transactions. :991-998 |
| ISSN: | 1364-5447 0300-9246 |
| Popis: | A new tetradentate proligand, 6,6′-bis(2,2-diphenyl-2-sulfanylethyl)-2,2′-bipyridine (H2L), involving two nitrogen bases and two thiols, has been synthesized. The crystal structure of its chloroiron(III) complex [FeL(Cl)] exhibits a five-co-ordinate iron in a distorted square-pyramidal structure including a long Fe–Cl axial bond. Its effective magnetic moment (µeff = 3.8 µB from 10 to 300 K) and its Mossbauer parameters [δ = 0.328(5) mm s–1 and ΔEQ = 2.543(9) mm s–1 at 293 K] are consistent with a pure intermediate S = spin state for the iron(III). This complex exhibits a sulfur-to-iron charge transfer absorption at 490 nm and a one-electron reduction wave at –415 mV (vs. SSCE). Upon reaction with tetrabutylammonium hydroxide it is converted into the µ-oxo complex [Fe2L2O], which has been characterized by mass spectral and elemental analyses. Its formation is reversible in dmf upon addition of trifluoroacetic acid in the presence of chloride anion, as shown by 1H NMR and UV/VIS spectroscopy and electrochemistry. The [FeL(Cl)] complex appears to be the first example of an iron(III) complex with a mixed nitrogen–sulfur co-ordination sphere in a pure S = ground spin state. |
| Databáze: | OpenAIRE |
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