Preparation of materials in the presence of hydrogen peroxide: from discrete or "zero-dimensional" objects to bulk materials.

Based on selected examples from the literature, this perspective aims to provide a short overview of synthetic methods using hydrogen peroxide and/or peroxidic species for the elaboration of discrete or zero-dimensional species, as well as mono-, bi- and tri-dimensional materials. There are several advantages in using peroxidic species: no foreign ion or organic ligand is introduced in the reaction medium, they are relatively cheap compared to costly alkoxides, for example, and in certain favorable cases these methods allow the selective formation of a given oxide polymorph. The materials prepared are used in several important technological applications such as electrochromism, gas sensing and electrochemistry but, in this review, special emphasis is placed on oxidation catalysis.

Mixed crystals containing the dioxo complex [[Ph3SiO]2VO2]- and novel pentacoordinated oxoperoxo complex [[Ph3SiO]2VO(O2)]-: X-ray crystal structure and assessment as oxidation catalysts.

[n-Bu4N][[Ph3SiO]2VO2] reacts with H2O2 to yield an oxoperoxo complex which crystallizes as a mixed-crystal compound, [P(C6H5)4][[(C6H5)3 SiO]2VO2]x[[(C6H5)3 SiO]2VO(O2)](1-x), 1(x = 0.57). It has been characterized by elemental analysis and spectroscopy (51V NMR, UV-visible and IR).

Redistribution and fluxionality in heteropolyoxoperoxo complexes: [PO4[M2O2(mu-O2)2(O2)2]2]3- with M = Mo and/or W.

When peroxotetramolybdophosphate, [(n-C4H9)4N]3[PO4[Mo2O2(mu-O2)2(O2)2]2], denoted (NBu4)3PMo4, and its tungsten(VI) analogue, (NBu4)3PW4, are mixed in acetonitrile at room temperature, redistribution occurs with the formation of three mixed-addenda species [PO4[Mo4-xWxO20]]3- (x = 1-3). The temperature dependence of the phosphorus-31 NMR spectra of a 1 1 mixture and of the pure salts, (NBu4)3PMo4 or (NBu4)3PW4, shows that [MO(O2)2] species are in chemical exchange, as are the [MOp] units of certain heteropolyacids (e.g.

Novel Distorted Pentagonal-Pyramidal Coordination of Anionic Oxodiperoxo Molybdenum and Tungsten Complexes.

Model compounds for silica surfaces modified with metal complexes are provided by the mononuclear anionic diperoxo species 1 and the dinuclear complex anions 2 (M = Mo, W). They were obtained in fair to nearly quantitative yields by the reactions of Ph SiOH and [Ph Si(OH)] O, respectively, with an aqueous solution of [MO(O ) (H O) ].