Spectroscopic and DFT Study of Tungstic Acid Peroxocomplexes

Abstract

The catalytic system formed by tungstic acid and its complexes with H2O2 and phenylphosphonic acid has been analyzed from the experimental and theoretical points of view. Previous structural studies by XRD proved the validity of the DFT proposed models and methodology. Hydrogen peroxide reacts with tungstic acid to form a peroxo complex. Vibrational and electronic spectra showed significant changes upon interaction with H2O2. The DFT and TD-DFT for IR and UV-vis calculations not only are in agreement with experimental data but also allow for a deeper characterization of the species formed in in situ conditions. A SCRF/PCM methodology was chosen to account for the solvent effect. The solvent effect of water was considered for geometry re-optimization of the structure and for the TD-DFT calculations.

Copper(II)‐Mediated Aromatic ortho‐Hydroxylation: A Hybrid DFT and Ab Initio Exploration

“…Solvation effects on the mechanism of aromatic ortho-hydroxylation: Exploring the role of solvent in transitionmetal-mediated reactions is a challenging task, especially if the geometries need to be reoptimized in the solvent phase. [88] Except for the calculations of redox potentials and absorption spectra, [89][90][91][92] the explicit consideration of solvent effects, for example, in mechanistic studies, with the full structural optimization of the solvated species, with either PCM or CPCM, is scarce. [93][94][95] The role of solvent is essential for our mechanistic study because the effect of the bulk solvent on the energetics of the reactant and transition states may favor one mechanism over another.…”

Cyclohexanone Oxidation over H3PMo12O40 Heteropolyacid via Two Activation Modes Microwave Irradiation and Conventional Method

“…In the second step, H2O2 intervenes to oxidize simultaneously the reduced phase of the POM and to form peroxospecies (oxidized peroxo-POMox). It has been reported in several studies that transition elements with high oxidation states (V(V), Nb(V), Mo(VI), and W(VI)) have a high affinity towards H2O2 [31][32][33][34][35]. This has as for consequence the formation of peroxocomplexes highlighted by several techniques (X-ray diffraction, FTIR, and Raman spectroscopies).…”

Adsorption structure of phenylphosphonic acid on an alumina surface

“…2. Table 1 represents a summary of the PPOA references, IRAS results and assignments [11][12][13][14][15][16]. The optical phonon of alumina was not observed, because its position is below 1000 cm À1 [17].…”