Mixed crystals containing the dioxo complex [{Ph3SiO}2VO2]−and novel pentacoordinated oxoperoxo complex [{Ph3SiO}2VO(O2)]−: X-ray crystal structure and assessment as oxidation catalysts
| Autor: | Jean-Marie Brégeault, Patrick Herson, Maxence Vennat |
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| Rok vydání: | 2004 |
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| Zdroj: | Dalton Trans.. :908-913 |
| ISSN: | 1477-9234 1477-9226 |
| DOI: | 10.1039/b400657g |
| Popis: | [n-Bu4N][{Ph3SiO}2VO2] reacts with H2O2 to yield an oxoperoxo complex which crystallizes as a mixed-crystal compound, [P(C6H5)4][{(C6H5)3 SiO}2VO2]x[{(C6H5)3 SiO}2VO(O2)]1−x, 1 (x = 0.57). It has been characterized by elemental analysis and spectroscopy (51V NMR, UV-visible and IR). The X-ray structure analysis reveals the presence of two interrelated anions: [{Ph3SiO}2VVO2]−, 1a, and [{Ph3SiO}2VVO(O2)]−, 1b with a cisoid geometry of the {VO(O2)}+ moiety. The two structures differ only slightly: anion 1a exhibits unusual tetrahedral coordination around the vanadium centre found in the precursor, whereas the geometry at the metal ion in 1b can be described as a trapezoidal pyramid. Steric constraints due to Ph3SiO− ligands and PPh4+ cations are responsible for this geometry. The reactivity of 1 in the C–C bond cleavage of 2-methylcyclohexanone under anaerobic conditions has been studied. The results suggest that peroxygen species are involved in the oxidative cleavage of C–C bonds of cycloalkanones. |
| Databáze: | OpenAIRE |
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