Venturello complex

The first examples of an electrostatie attachment of POMs on solid supports are dated to the mid 1980. Baba et al. reported immobilization of heteropolyacids on the anion-exchange resin Amberlist-15 [68]. Later on, this type of the support was successfully used by Jacob s group to immobilize the Venturello complex P04[W0(02)2]4, well known as highly selective homogeneous catalyst for H202-based epoxidation of alkenes... 

Both of these species are believed to function through an intermediate known as the Venturello complex (Figure 2.26) 84 one of the peroxo oxygens is... 

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... 

NMR spectroscopy and electrospray mass spectrometry.376 Other research in this area has focused mainly on the catalytic activities of the Venturello anion, [P04 W0(02)2 2]3, 377 and complexes that are structurally related to this. These and other peroxo-containing heteropolyanions that have been reported recently are summarized in Table 26. 

The Venturello-Ishii chemistry is extraordinarily complex. There may be a multitude of weaker epoxidizing agents that are peroxotungstates of higher nuclearity. 

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