Tungsten tetrakis complexes

Extension of these WL4 complexes to complexes not involving 8-quinolinol derivatives has included a number of substituted tetrakis-(picolinato)tungsten (IV) complexes (2, where Z = H, CH3, or C2H5 and the analogous 3-hydroxypicolinato complex) (3). Other species reported previously include the 2-pyrazinecarboxylato and 1-isoquino-linecarboxylato species, W(pzc)4 (3) and W(iqc)4 (4) (3), and the spectrally supported W(nq)4 and W(hqa)4 (2). Complexes not previously reported include W(tbq) 4 and the quadridentate Schiff base chelate W(dsp)2 (5 ), for which at least two isomers have been observed. 

Hydrogen peroxide may be efficiently employed for the epoxidation of unfunctionalized aikenes in the presence of polyoxo complexes of tungsten and molybdenum . Venturello and coworkers first developed a phosphotungstate catalyst , with particular emphasis on the tetrakis(diperoxotungsto)phosphate anion P04[W(0)(02)2]4 , 37 , that in conjunction with H2O2 and a lipophilic tetra-alkylammonium salt Q+X as phase transfer... 

B2FgN4WCgHi2, Tungsten(2+), tetrakis-(acetonitrile)dinitrosyl-, cis-, bis[tetrafluoroborate(l —)], 28 66 02B2FgN4WCgHi2, Tungsten(II), tetrakis-(acetonitrile)dinitrosyl-, cis-, bis[tetra-fluoroborate(l —)], 26 133 O2C, Carbon dioxide, rhenium complex, 26 111... 

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