نتایج جستجو برای: polyoxometalate

تعداد نتایج: 904  

Journal: :Dalton transactions 2014
Qiao Gao Fengyan Li Yuchao Wang Lin Xu Jie Bai Ya Wang

A novel organic-inorganic hybrid of triethanolamine linked covalently with a new building block of {VMo6O25} was synthesized in aqueous solution, and the hybrid was further assembled with copper-triethanolamine complexes to form a ring-like structure. This work represents an advance in the organic functionalization of polyoxometalate performed in aqueous solution instead of an organic solvent.

Journal: :Chemistry - A European Journal 2016

Journal: :Dalton transactions 2016
Thi Kim Nga Luong Pavletta Shestakova Tatjana N Parac-Vogt

The catalytic hydrolysis of a phosphoester bond in the DNA-model substrate 4-nitrophenyl phosphate (NPP) promoted by Zr(iv)-substituted Wells-Dawson Na14[Zr4(P2W16O59)2(μ3-O)2(OH)2(H2O)4]·57H2O polyoxometalate (ZrWD 4 : 2) was followed by means of (1)H and (31)P NMR spectroscopy. The hydrolytic reaction proceeded with a rate constant of 8.44 (±0.36) × 10(-5) s(-1) at pD 6.4 and 50 °C, represent...

Journal: :Small 2013
Xiaoxing Ke Stuart Turner Mildred Quintana Caroline Hadad Alejandro Montellano-López Mauro Carraro Andrea Sartorel Marcella Bonchio Maurizio Prato Carla Bittencourt Gustaaf Van Tendeloo

Polyoxometalates (POMs) are a well-known class of discrete early transition metal-oxide nanoclusters. This class of molecular metal oxides is unmatched not only in terms of structural diversity but also in reactivity and relevance to analytical chemistry, catalysis, medicine, and nanoscience. [ 1–3 ] The integration of POMs into functional architectures and devices requires the development of m...

Journal: :Journal of the American Chemical Society 2002
Shaoqin Liu Dirk G Kurth Bjoern Bredenkötter Dirk Volkmer

Using electrostatic layer-by-layer self-assembly (ELSA), the formation of multilayers with polyelectrolytes and nanoscopic polyoxometalate (POM) clusters of different sizes and charges is investigated. The multilayers are characterized by UV-vis absorption spectroscopy, optical ellipsometry, cyclic voltammetry, and atomic force microscopy. In all cases, it is possible to find experimental condi...

Journal: :Chemical communications 2006
Galia Maayan Benjamin Ganchegui Walter Leitner Ronny Neumann

Selective aerobic oxidation of benzylic alcohols and of activated aromatic hydrocarbons occurs in supercritical CO2 as reaction medium using H5PV2Mo10O40 as a quasi-heterogeneous catalyst without further additives or co-solvents; efficient recycling is possible and no metal leaching is detectable in the product stream.

Journal: :Chemical communications 2013
Yuji Kikukawa Yoshiyuki Kuroda Kosuke Suzuki Mitsuhiro Hibino Kazuya Yamaguchi Noritaka Mizuno

By the reaction of TBA(4)H(4)[γ-SiW(10)O(36)] (TBA = tetra-n-butylammonium) with AgOAc (OAc = acetate) using dimethylphenylsilane as a reductant in acetone, a unique polyoxometalate containing a discrete octahedrally shaped [Ag(6)](4+) cluster, TBA(8)[Ag(6)(γ-H(2)SiW(10)O(36))(2)]·5H(2)O, could be synthesized, and the molecular structure was determined.

Journal: :Dalton transactions 2011
Xing Meng Chao Qin Xin-Long Wang Zhong-Min Su Bo Li Qi-Hua Yang

Immobilization of the chiral salen-metal complex [Mn(III)(salen)(H(2)O)(2)ClO(4)] on the Keggin-type polyoxometalate (POM) skeletons leads to the isolation of POM derivatives functionalized with chiral salen-metal complexes, which represent the first examples of introducing chiral salen-metal complexes into the POM systems.

Journal: :Organic letters 2007
Sanzhong Luo Jiuyuan Li Hui Xu Long Zhang Jin-Pei Cheng

Chiral amine and polyoxometalate (POM) acids were combined to give highly efficient, stereoselective, and recoverable enamine-based catalysts. Less than 1 mol % of chiral amine loading was sufficient for good catalytic activity, and the catalyst could be recovered and reused 6 times with unchanged enantioselectivity and slightly decreased activity.

Journal: :Chemical communications 2005
Galia Maayan Ronny Neumann

Ag and Ru nanoparticles stabilized by H5PV2Mo10O40, prepared by a sequence of redox reactions and supported on alpha-alumina, were effective catalysts for the direct aerobic epoxidation of alkenes in the liquid phase.

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