Water-soluble niobium peroxo complexes as precursors for the preparation of Nb-based oxide catalysts

New Insights on the Oxidation of Unsaturated Fatty Acid Methyl Esters Catalyzed by Niobium(V) Oxide. A Study of the Catalyst Surface Reactivity

“…The appearance of these bands is associated with the formation of a η 2 -peroxo system on the catalyst surface, which is usually indicative of a large number of structural defects associated with the NbO7 and NbO8 sites [20,21,66,67]. The signals observed at 540 and 892 cm −1 can be attributed to the symmetric and asymmetric stretches of the NbO2 group, respectively and associated to the formation of a di-η 2 -peroxo system with cis-lateral geometry [66,67]. The maximum value for the ratio between the bands at 892 and 878 cm −1 is reached after five minutes as can be seen in Figure 2 (I(f)).…”

Spectroscopic and Structural Characterizations of Novel Water‐Soluble Peroxo[polyaminocarboxylato bis(N‐oxido)]niobate(V) Complexes

“…Because peroxoniobium compounds are soluble in water, they are adequate candidates for that purpose. Several such complexes have already been described in the literature; they correspond either to homoleptic tetraperoxoniobates of general formula (A I ) 3 [9,11] and K[Nb(O 2 ) 2 (L) 2 ]·3H 2 O (L ϭ 8-hydroxyquinolinate). [12] As far as the peroxo(polyaminocarboxylato) compounds are concerned, only a few studies have been reported and they are essentially restricted to the edta(peroxo) compound [a] and its solution chemistry.…”

Crystal structure of ammonium oxo(peroxo)(pyridine-2,6-dicarboxylato- N,O,O′)aquavanadate(V), (NH4)[VO(O2)(H2O)(C7H3NO4)]

“…In the frame of research aimed at developing new synthetic procedures of oxide materials, the so-called chelate method, which consists in the thermal decomposition of solid metal precursors obtained from a solution of the complexed metals, was shown to be an appropriate way to get multimetallic oxides [1,2]. During investigations to identify new water-soluble vanadium compounds that could be used as precursors for V-based oxides, the title compound was isolated.…”

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Source of materialDark red crystals suitable for X-ray diffraction analysis were obtained by keeping at 253 K a 1:1:1 (molar ratio) mixture of ammonium vanadate, NH 4VO3, pyridine-2,6-dicarboxylic acid, C 7H5NO4, and hydrogen peroxide in a water-ethanol mixture.

DiscussionIn the frame of research aimed at developing new synthetic procedures of oxide materials, the so-called chelate method, which consists in the thermal decomposition of solid metal precursors obtained from a solution of the complexed metals, was shown to be an appropriate way to get multimetallic oxides [1,2]. During investigations to identify new water-soluble vanadium compounds that could be used as precursors for V-based oxides, the title compound was isolated.

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