RT Journal Article
T1 Phosphonate Decomposition-Induced Polyoxomolybdate Dumbbell-Type Cluster Formation: Structural Analysis, Proton Conduction, and Catalytic Sulfoxide Reduction
A1 Armakola, Eirini
A1 Salcedo, Inés R.
A1 Bazaga-García, Montse
A1 Mezei, Gellert
A1 Cabeza-Díaz, Aurelio
A1 Fernandes, Tiago A.
A1 Kirillov, Alexander M.
A1 Demadis, Konstantinos D.
K1 Conductividad eléctrica
K1 Fósforo - Compuestos
AB The reaction of MoO4^2− with a number of phosphonic acids [bis-(phosphonomethyl)glycine, R,S-hydroxyphosphonoacetic acid, 1-hydroxyethane-1,1-diphosphonic acid, phenylphosphonic acid, aminotris(methylene phosphonic acid), and 1,2- ethylenediphosphonic acid] under oxidizing (H2O2) hydrothermal conditions at low pH leads to rupture of the P−C bond, release of orthophosphate ions, and generation of the octanuclear, phosphate-bridged, polyoxometalate molybdenum cluster(NH4)5[Mo8(OH)2O24(μ8-PO4)](H2O)2 (POMPhos). This cluster has been fully characterized and its structure determined. It was studied as a proton conductor, giving moderate values of σ = 2.13 × 10−5 S·cm−1 (25 °C) and 1.17 × 10−4 S·cm−1 (80 °C) at 95% relative humidity, with Ea = 0.27 eV. The POMPhos cluster was then thermally treated at 310 °C, yielding(NH4)2.6(H3O)0.4(PO4Mo12O36) together with an amorphous impurity containing phosphate and molybdenum oxide. Thisproduct was also studied for its proton conductivity properties, giving rise to an impressively high value of σ = 2.43 × 10−3 S·cm−1 (25 °C) and 6.67 × 10−3 S·cm−1 (80 °C) at 95% relative humidity, 2 orders of magnitude higher than those corresponding to the “as-synthesized” solid. The utilization of POMPhos in catalytic reduction of different sulfoxides was also evaluated. POMPhos acts as an efficient homogeneous catalyst for the reduction of diphenyl sulfoxide to diphenyl sulfide, as amodel reaction. Pinacol was used as a low-cost, environmentally friendly, and highly efficient reducing agent. The effects ofdifferent reaction parameters were investigated, namely the type of solvent and reducing agent, presence of acid promoter,reaction time and temperature, loading of catalyst and pinacol, allowing to achieve up to 84−99% yields of sulfide productsunder optimized conditions. Substrate scope was tested on the examples of diaryl, alkylaryl, dibenzyl, and dialkyl sulfoxides andexcellent product yields were obtained.
PB ACS publications
YR 2019
FD 2019-08-12
LK https://hdl.handle.net/10630/20989
UL https://hdl.handle.net/10630/20989
LA eng
NO Inorg. Chem. 2019, 58, 11522−11533
NO Proyecto MAT2016-77648-R del MINECO y proyectos P12-FQM-1656 y FQM-113 de la Junta de Andalucía
DS RIUMA. Repositorio Institucional de la Universidad de Málaga
RD 20 ene 2026