Topic
Polyoxometalate
About: Polyoxometalate is a research topic. Over the lifetime, 3493 publications have been published within this topic receiving 94123 citations. The topic is also known as: POM.
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TL;DR: A derivative of the Dawson polyoxometalate functionalized with one remote bipyridine coordination site has been synthesized and combined with the neutral {Re(CO)3Br} moiety and the new Re(I)-hybrid was characterized by various analytical techniques.
Abstract: A derivative of the Dawson polyoxometalate [P2V3W15O62]9− functionalized with one remote bipyridine coordination site (2) has been synthesized and combined with the neutral {Re(CO)3Br} moiety. The new ReI-hybrid (3) was characterized by various analytical techniques. Hybrid 3 exhibits several redox processes on a wide range of potentials with reductions centered on V(V), W(VI) and the organic ligand in order of decreasing potential. Both units, the polyoxometalate and the transition metal complex, retain their intrinsic properties in the hybrid 3, which displays photosensitization in the UV region with tailing into high-energy visible region.
32 citations
TL;DR: Co-POM enabled the hydrogen evolution and dehydrogenation of tetrahydroisoquinoline without the presence of any other additives and indicated the advantages of the combining functional polyoxometalate-based catalysts and porous characters of the coordination polymers for the development of highly active heterogeneous catalysts.
Abstract: Dehydrogenation of the tetrahydroisoquinoline derivatives coupled with hydrogen production is important for hydrogen storage applications. Herein, we formulated a new system that embedded Dawson-type polyoxometalates as efficient photosensitizers into the pores of redox-active coordination polymers for the light-driven photocatalytic oxidative Mannich reaction and hydrogen evolution. In the designed Co-POM polymer, UV light excitation gives the excited state of the Dawson-type polyoxometalate first to oxidize electron donors or substrates; the reduced form (i.e., heteropolyblue) adsorbs visible light to achieve a new excited state, which reduced the cobalt redox sites and facilitates hydrogen evolution reaction. The photosensitizer recovered to the ground state, completing the catalytic cycle. Under the optimized conditions, Co-POM enabled the hydrogen evolution and dehydrogenation of tetrahydroisoquinoline without the presence of any other additives. The high catalytic efficiency and robustness indicated...
31 citations
TL;DR: The excellent thermal sensing capability of a multinuclear lanthanide polyoxometalate in the cryogenic region (<100 K) is presented for the first time and a very efficient energy transfer between Mo-O→Tb3+→Eu3+.
Abstract: Here, the excellent thermal sensing capability of a multinuclear lanthanide polyoxometalate in the cryogenic region (<100 K) is presented for the first time. Up till now, no lanthanide polyoxometalates have been studied for their use as ratiometric luminescent thermometers. The investigated Tb3+ polyoxometalate cluster is doped with 1.6% (P1) and 8.4% (P2) of Eu3+ ions. When excited into the Mo-O charge transfer bands, at room temperature only the emission of the Eu3+ ions is observed suggesting a very efficient energy transfer between Mo-O→Tb3+→Eu3+. Only in the cryogenic region the emission of Tb3+ is also witnessed.
31 citations
TL;DR: The anion is the second example of a new class of polyoxometalates that resemble Dawson anions but where the two pole caps of three edge-sharing MoO(6) octahedra in the latter are replaced by other units, in this case tetrahedral borate sharing corners with three phenylphosphonic groups, [(OB)(O(3)P-Ph)(3].
Abstract: The title polyanion is the first hybrid borophosphate−phenylphosphonate polyoxometalate. It was structurally characterized as its imidazolium salt, (C3N2H5)5[Mo12O30(BPO4)2(O3P-Ph)6]·H2O (monoclini...
31 citations
TL;DR: X-ray photoelectron spectroscopy of Au NPs protected by a series of POM ligands revealed that binding energies of electrons in the Au 4f7/2 and 4f5/2 atomic orbitals decreased, providing a direct correlation between the electronic effects of the POMs bound to the surfaces of the Au Nps and the rates of CO oxidation by O2.
Abstract: Metal oxide cluster-anion (polyoxometalate, or POM) protecting ligands, [α-PW11O39]7– (1), modify the rates at which 14 nm gold nanoparticles (Au NPs) catalyze an important model reaction, the aerobic (O2) oxidation of CO to CO2 in water. At 20 °C and pH 6.2, the following stoichiometry was observed: CO + O2 + H2O = CO2 + H2O2. After control experiments verified that the H2O2 product was sufficiently stable and did not react with 1 under turnover conditions, quantitative analysis of H2O2 was used to monitor the rates of CO oxidation, which increased linearly with the percent coverage of the Au NPs by 1 (0–64% coverage, with the latter value corresponding to 211 ± 19 surface-bound molecules of 1). X-ray photoelectron spectroscopy of Au NPs protected by a series of POM ligands (K+ salts): 1, the Wells–Dawson ion [α-P2W18O62]6– (2) and the monodefect Keggin anion [α-SiW11O39]8– (3) revealed that binding energies of electrons in the Au 4f7/2 and 4f5/2 atomic orbitals decreased as a linear function of the POM ...
31 citations