Complexes of palladium(II) and platinum(II) with the PW11O7−39 heteropolyanion as catalytically active species in benzene oxidation

Studies on the structural change of a reaction-controlled phase-transfer [π-C5H5NC16H33]3{PO4[WO3]4} catalyst during the selective oxidation of cyclopentene to glutaric acid with aqueous H2O2

“…4(a) [11]. Based on the results of the literatures [34][35][36], the IR band at 886 cm À1 can be attributed to the mode of y(W-O b -W) (corner-sharing). However, no band at 815 cm À1 (attributed to y(W-O c -W) (edge-sharing)) is observed, indicating the absence of polymerization of W species.…”

Noble Metals in Polyoxometalates

“…The interaction between monolacunary Keggin- [28,58,59,[62][63][64][65][66][67][68][69][70] Unfortunately no X-ray structural investigations of any products obtained were carried out and confident assignment of L-structures to these compounds cannot be confirmed. Most studies have been carried out with the phosphorus-centered lacunary species, the products often being formulated as [PM 11 8À which would imply uncommon and presumably paramagnetic octahedral or square-pyramidal Pd II centers.…”

“…Recent studies suggest a different explanation of these results in terms of the S-structure species that are described in Section 2.3.3. Reports of the activity of the notfully-characterized products in homogeneous or biphasic solution, or supported on alumina, include catalytic oxidation of allylic alcohols, [28b] hydrogenation of arenes, [67] benzene oxidation, [63,69] reduction of nitrogen oxides by methane, [64] and electrocatalytic reduction of nitrite and H 2 O 2 . [65,66] Metal nanoparticles prepared by reduction of "K 5 [PPdW 11 O 39 ]" with H 2 have been shown to be efficient catalysts for Suzuki-, Heck-, and Stille-type C À C and C À N coupling reactions of bromo-and chloroarenes.…”

“…[70] 2. , but no analytical evidence for this was presented. [63] The reaction of [ , isolated as the tetra-n-butylammonium salt. [71] The NMR spectra of the product showed only one 31 P and seven 183 W signals (instead of the expected two and nine lines).…”

“…[69,78,83] Reaction (16-2n)À , [114] rather than incorporation of Pd II into the vacancy of the POM which would result in Lstructure complexes, as had been previously supposed (see Section 2.2.5). [28,58,59,[62][63][64][65][66][67][68][69][70] (16-2n)À polyanion can exist as anti and syn isomers with respect to the relative orientation of the POM ligands ( Figure 11). 31 P and 183 W NMR spectroscopy studies showed all three POMs to be stable in aqueous and organic media with no apparent facile syn-anti isomerization.…”