Structural and stereodynamic studies on molecular early transition metal derivatives V. NMR study of isolated tungsten dioxofluoride Adducts of type WO2F3L-
1979; Elsevier BV; Volume: 32; Linguagem: Inglês
10.1016/s0020-1693(00)91657-8
ISSN1873-3255
AutoresMichèle Postel, Jean G. Riess, J. Y. CALVES, Jacques E. Guerchais,
Tópico(s)Carbon dioxide utilization in catalysis
ResumoAbstract The title compounds (L = phosphine oxide, pyridine N-oxides)have been isolated and characterized, and their ClCH 2 CN so1utions studied by variabletemperature 1 H, 19 F and 31 PNMR. A detailedinvestigation on Et 4 N[WO 2 F 3 (OPMe 3 )] showsthat the F atom trans to an oxo ligand, as well as the OPMe 3 ligand trans to the other oxo ligand in thecis-dioxostructure A, are rapidly dissociated on the NMRtimescale, while the apical F atoms trans to each otherare not, which illustrates the trans-labilizing effect ofthe oxo ligands. Upon ageing new species are formed in the solutions, including WO 2 F 2 [OPMe 3 2 ,[WO 2 F 3 (CICH 2 CN)],WO 2 F 2 (ClCH 2 CN) 2 , F- and OPMe 3 An equilibrium situation is reached after 4 days' heating at 80°C. The neutral WO 2 F 2 (OPMe 3 ) 2 is then largely predominant. Material balance calculationsindicate that polynuclear species are also likely to be present.
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