Synthesis and characterization of new paramagnetic tetraaryl derivatives of chromium and molybdenum
| Autor: | Conrado Rillo, Antonio Martín, Ma Angeles García-Monforte, Juan Forniés, Babil Menjón, Pablo J. Alonso |
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| Rok vydání: | 2007 |
| Předmět: |
Cyclic voltammetry
Organomolybdenum Stereochemistry chemistry.chemical_element Electronic exchange Biochemistry Medicinal chemistry law.invention Inorganic Chemistry Metal Organochromium chemistry.chemical_compound Chromium Paramagnetism law Materials Chemistry Physical and Theoretical Chemistry Homoleptic Electron paramagnetic resonance Homoleptic compounds Organic Chemistry Comproportionation chemistry Molybdenum Yield (chemistry) visual_art visual_art.visual_art_medium EPR spectroscopy |
| Zdroj: | Digital.CSIC. Repositorio Institucional del CSIC instname |
| ISSN: | 0022-328X 2005-0860 |
| Popis: | 12 pages, 10 figures, 5 tables, 2 schemes, 1 appendix. The low-temperature reaction of [CrCl3(thf)3] with LiC6H3Cl2-2,6 yields the organochromium(III) compound [Li(thf)4][CrIII(C6H3Cl2-2,6)4] (1) in 48% yield. The homoleptic, anionic species [CrIII(C6H3Cl2-2,6)4]− is electrochemically related to the neutral one [CrIV(C6H3Cl2-2,6)4] (2) through a reversible one-electron exchange process (E1/2 = 0.16 V, ΔEp = 0.09 V, ipa/ipc = 1.18). Compound 2 was isolated in 74% yield by chemical oxidation of 1 with [N(C6H4Br-4)3][SbCl6]. Attempts to prepare the salt [NBu4][CrIII(C6Cl5)4] (4) by direct arylation of [CrCl3(thf)3] with LiC6Cl5 in the presence of [NBu4]Br gave the organochromium(II) salt [NBu4]2[CrII(C6Cl5)4] (3) instead, as the result of a reduction process. The salt [NBu4][CrIII(C6Cl5)4] (4) was cleanly prepared by comproportionation of 3 and [CrIV(C6Cl5)4]. The reaction of [MoCl4(dme)] with LiC6Cl5 in Et2O solution proceeded with oxidation of the metal center to give the paramagnetic (S = 1/2), five-coordinate salt [Li(thf)4][MoVO(C6Cl5)4] (5). The crystal and molecular structures of 1 and 2 have been established by X-ray diffraction methods. The magnetic properties of 1 and 4 (S = 3/2) as well as those of 2 (S = 1) have been established by EPR spectroscopy as well as by ac and dc magnetization measurements. This work was supported by the Spanish MEC (DGI)/ FEDER (Projects CTQ2005-08606-C02-01, BFU2005- 07422-C02-02, and MAT2005-1272) and the Gobierno de Aragón (Grupo de Excelencia: Química Inorgánica y de los Compuestos Organometálicos). |
| Databáze: | OpenAIRE |
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