821-55-6Relevant academic research and scientific papers
Ru(iii) -based polyoxometalate tetramers as highly efficient heterogeneous catalysts for alcohol oxidation reactions at room temperature
Li, Huafeng,Ma, Pengtao,Niu, Jingyang,Song, Junpeng,Wang, Jingping,Wang, Yaqiong,Zhao, Xue,Zou, Yan
, p. 12664 - 12673 (2021/09/28)
A novel ruthenium-containing polyoxometalate-based organic-inorganic hybrid, K4Na9H7.4[(AsW9O33)4(WO2)4{Ru3.2(C3H3N2)2}]·42H2O (1), was successfully synthesized by a one-step hydrothermal method under acidic conditions, which applied a self-assembly strategy between inorganic polyoxometalate based on trivacant [B-α-AsW9O33]9?{AsW9} fragments and an organic ligand, imidazole (C3H4N2). Compound1was further characterized by single-crystal X-ray diffraction, PXRD, IR spectroscopy, UV-Vis spectroscopy, ESI-MS, elemental analysis and TGA. Single-crystal X-ray diffraction data reveal that the polyanion consists of four trivacant Keggin-type polyanion {AsW9} building blocks bridged by four {WO6} units, leading to a crown-shaped tetrameric structure [(AsW9O33)4(WO2)4{Ru3.2(C3H3N2)2}]20.4?. The ESI-MS result reveals that the polyanion unit has excellent structural integrity in water. Moreover, the catalysis study of1was also further investigated, and the experimental results indicate heterogeneous catalyst1presents high efficiency (yield = 98%), excellent selectivity (>99%), and good recyclability for the oxidation of 1-(4-chlorophenyl)ethanol to 4′-chloroacetophenone with commercially available 70% aqueoustert-butyl hydroperoxide {TBHP (aq.)} as the oxidant at room temperature.
Hydration of Alkynes to Ketones with an Efficient and Practical Polyoxomolybdate-based Cobalt Catalyst
Xie, Ya,Wang, Jingjing,Wang, Yunyun,Han, Sheng,Yu, Han
, p. 4985 - 4989 (2021/10/12)
Hydration of alkynes to ketones is one of the most atom economical and universal methods for the synthesis of carbonyl compounds. However, the basic reaction usually requires organic ligand catalysts or harsh reaction conditions to insert oxygen into the C≡C bond. Here, we report an inorganic ligand supported cobalt (III) catalyst, (NH4)3[CoMo6O18(OH)6], which is supported by a central cobalt (III) mononucleus and a ring-shaped pure inorganic ligand composed of six MoVIO6 octahedrons to avoid the disadvantages of expensive and unrecyclable organic ligand catalysts or noble metal catalysts. Under mild conditions, the cobalt (III) catalyst can be used for the hydration of alkynes to ketones. The catalyst is non-toxic, green, and environment friendly. The catalyst can be recycled at least six times with high activity. According to control experiments, a reasonable mechanism is provided.
The effect of the position of cross-linkers on the structure and microenvironment of PPh3moiety in porous organic polymers
Ji, Guangjun,Li, Cunyao,Xiao, Dong,Wang, Guoqing,Sun, Zhao,Jiang, Miao,Hou, Guangjin,Yan, Li,Ding, Yunjie
, p. 9165 - 9174 (2021/04/16)
Three trivinyl functionalization triphenylphosphine (3vPPh3)-based porous organic ligands (3vPPh3-POLs) with cross-linkers in different positions were obtained through solvothermal polymerization. By simply changing the position of the cross-linkers (vinyl groups) attached to the PPh3monomer, the resulting porous organic polymer (POP) materials acquired diverse hierarchical porous structures, and the microenvironment of POPs was sequently regulated. Among the three 3vPPh3-POLs, the BET surface areas ranged from 168 to 1583 m2g?1, while the proportion of micropores changed from 0.0% to 52.0%. Benefiting from the unique structure, Rh ions could be coordinated and dispersed as a single site inm-3vPPh3-POL to form HRh(CO)2(PPh3-POL)2species, which endowed the Rh/m-3vPPh3-POL catalyst with an activity similar to that in the homogeneous system, anl/bratio (the ratio of the linear aldehyde to the branched aldehyde) approximately as high as 10, and stability for a duration of more than 500 h in the hydroformylation of 1-octene.
Production of chiral alcohols from racemic mixtures by integrated heterogeneous chemoenzymatic catalysis in fixed bed continuous operation
Carceller, Jose Miguel,Climent, Maria J.,Corma, Avelino,Iborra, Sara,Mifsud, Maria
, p. 2767 - 2777 (2020/06/17)
Valuable chiral alcohols have been obtained from racemic mixtures with an integrated heterogeneous chemoenzymatic catalyst in a two consecutive fixed catalytic bed continuous reactor system. In the first bed the racemic mixture of alcohols is oxidized to the prochiral ketone with a Zr-Beta zeolite and using acetone as the hydrogen acceptor. In the second catalytic bed the prochiral ketone is stereoselectively reduced with an alcohol dehydrogenase (ADH) immobilized on a two dimensional (2D) zeolite. In this process, the alcohol (isopropanol) formed by the reduction of acetone in the first step reduces the cofactor in the second step, and the full reaction cycle is in this way internally closed with 100% atom economy. A conversion of about 95% with ~100% selectivity to either the (R) or the (S) alcohol has been obtained for a variety of racemic mixtures of alcohols.
Photocontrolled Cobalt Catalysis for Selective Hydroboration of α,β-Unsaturated Ketones
Beltran, Frédéric,Bergamaschi, Enrico,Funes-Ardoiz, Ignacio,Teskey, Christopher J.
supporting information, p. 21176 - 21182 (2020/09/17)
Selectivity between 1,2 and 1,4 addition of a nucleophile to an α,β-unsaturated carbonyl compound has classically been modified by the addition of stoichiometric additives to the substrate or reagent to increase their “hard” or “soft” character. Here, we demonstrate a conceptually distinct approach that instead relies on controlling the coordination sphere of a catalyst with visible light. In this way, we bias the reaction down two divergent pathways, giving contrasting products in the catalytic hydroboration of α,β-unsaturated ketones. This includes direct access to previously elusive cyclic enolborates, via 1,4-selective hydroboration, providing a straightforward and stereoselective route to rare syn-aldol products in one-pot. DFT calculations and mechanistic experiments confirm two different mechanisms are operative, underpinning this unusual photocontrolled selectivity switch.
Selective oxidation of exogenous substrates by a bis-Cu(III) bis-oxide complex: Mechanism and scope
Large, Tao A.G.,Mahadevan, Viswanath,Keown, William,Stack, T. Daniel P.
, p. 782 - 792 (2019/01/03)
Cu(III)2(μ-O)2 bis-oxides (O) form spontaneously by direct oxygenation of nitrogen-chelated Cu(I) species and constitute a diverse class of versatile 2e?/2H+ oxidants, but while these species have attracted attention as biomimetic models for dinuclear Cu enzymes, reactivity is typically limited to intramolecular ligand oxidation, and systems exhibiting synthetically useful reactivity with exogenous substrates are limited. OTMPD (TMPD = N1, N1, N3, N3-tetramethylpropane-1,3-diamine) presents an exception, readily oxidizing a diverse array of exogenous substrates, including primary alcohols and amines selectively over their secondary counterparts in good yields. Mechanistic and DFT analyses suggest substrate oxidation proceeds through initial axial coordination, followed by rate-limiting rotation to position the substrate in the Cu(III) equatorial plane, whereupon rapid deprotonation and oxidation by net hydride transfer occurs. Together, the results suggest the selectivity and broad substrate scope unique to OTMPD are best attributed to the combination of ligand flexibility, limited steric demands, and ligand oxidative stability. In keeping with the absence of rate-limiting C–H scission, OTMPD exhibits a marked insensitivity to the strength of the substrate Cα–H bond, readily oxidizing benzyl alcohol and 1-octanol at near identical rates.
A Stable Polyoxometalate-Based Metal-Organic Framework as Highly Efficient Heterogeneous Catalyst for Oxidation of Alcohols
Li, Dandan,Xu, Qiaofei,Li, Yingguang,Qiu, Yueting,Ma, Pengtao,Niu, Jingyang,Wang, Jingping
, p. 4945 - 4953 (2019/04/25)
A novel copper-containing 3D polyoxometalate-based metal-organic framework (POMOF), H[Cu5ICuII(pzc)2(pz)4.5{P2W18O62}]·6H2O (HENU-1, HENU = Henan University; Hpzc = pyrazine-2-carboxylic acid, pz = pyrazine), was successfully isolated by a one-step hydrothermal method. In this compound, the {P2W18} polyanion acts as a seven-connected linker bridging adjacent 2D double-layer networks, as well as a template to induce the formation of the desired 3D framework. Particularly, the pz ligands are generated from pzc ligands in situ during the reaction process. HENU-1 exhibits not only good stability in air but also tolerance to acidic and basic media. It was first employed as a highly efficient heterogeneous catalyst for the oxidation of 1-phenylethanol into acetophenone, which shows 97% yield using tert-butyl hydroperoxide as oxidant with a turnover frequency of up to 9690·h-1, and was reused for at least five cycles without significant catalytic activity loss. No POM leaching or framework decomposition was observed in our study.
Pyrazine dicarboxylate-bridged arsenotungstate: Synthesis, characterization, and catalytic activities in epoxidation of olefins and oxidation of alcohols
Ma, Xinyi,He, Peipei,Xu, Baijie,Lu, Jingkun,Wan, Rong,Wu, Hechen,Wang, Yuan,Ma, Pengtao,Niu, Jingyang,Wang, Jingping
, p. 12956 - 12963 (2019/09/07)
A praseodymium(iii)-containing arsenotungstate K16H15Li7[Pr2(H2O)3(pzdc)As3W29O103]2·38H2O (1) (pzdc = pyrazine-2,3-dicarboxylic acid) was synthesized by a conventional aqueous solution method and characterized by elemental analysis, IR spectroscopy, thermogravimetric analysis (TGA), powder X-ray diffraction (PXRD), and single crystal X-ray diffraction. Structural analysis revealed that compound 1 was constructed by two identical subunits {Pr2(H2O)3(AsW9O33)3W2O4} bridged together by two pzdc ligands. In addition, compound 1 could act as an efficient catalyst for the epoxidation of olefins and oxidation of alcohols with hydrogen peroxide (H2O2) as the oxidant. In particular, the turnover frequency (TOF) in the oxidation of 1-phenylethanol reached up to 10170 h-1, which is higher than that of previously reported catalysts.
Polyoxovanadate catalysts for oxidation of 1-phenyl ethanol: From the discrete [V4O12]4- and [V10O28]6- anions to the anionic [V6O17]:N4 n - Coordination polymer
Wang, Ke,Xu, Qiaofei,Ma, Pengtao,Zhang, Chao,Wang, Jingping,Niu, Jingyang
, p. 6273 - 6279 (2018/10/23)
Three polyoxovanadate-based hybrids {[Ru(phen)3]2[V4O12]}·13H2O (1), [Ru(phen)3]2[V10O28]·15H2O (2), and [Ru(phen)3]2[V6O17]Cl·11H2O (3) (phen = 1,10-phenanthroline) were prepared under hydrothermal conditions and characterized by electron paramagnetic resonance (EPR) spectroscopy, infrared spectroscopy (IR), powder X-ray diffraction (PXRD), thermogravimetric (TG) analysis, X-ray photoelectron spectroscopy (XPS), and single crystal X-ray diffraction analysis. Although the structures of both the cyclic vanadate [V4O12]4- and the [V10O28]6- anions are well-known, interestingly, a novel 1-dimensional (1-D) coordination polymer [V6O17]n4n- anion was constructed from tetranuclear [V4O12]4- and dinuclear [V2O7]4- building blocks, which were linked alternately through corner-shared oxygen atoms. Furthermore, the negative charges of polyoxovanadate [V4O12]4-, [V10O28]6- and [V6O17]4- anions were balanced by two [Ru(phen)3]2+/3+ complex cations. The catalytic properties of compounds 1-3 for the oxidation of 1-phenyl ethanol by tert-butyl hydroperoxide (TBHP) were investigated, and the results demonstrated that 1 and 3 exhibited excellent catalytic activities for the oxidation of 1-phenyl ethanol under mild catalytic conditions.
Copper based coordination polymers based on metalloligands: Utilization as heterogeneous oxidation catalysts
Kumar, Gulshan,Hussain, Firasat,Gupta, Rajeev
, p. 16985 - 16994 (2019/01/03)
This work presents the synthesis and characterization of two Cu(ii)-based coordination polymers prepared by utilizing two different Co(iii)-based metalloligands offering appended arylcarboxylic acid groups. Both coordination polymers are three-dimensional in nature and present pores and channels filled with water molecules. Both coordination polymers function as heterogeneous catalysts for the epoxidation of various olefins using O2 while employing isobutyraldehyde as the coreductor and for peroxide-mediated oxidation of assorted benzyl alcohols. The catalytic results illustrate efficient oxidation reactions, whereas the hot-fltration test and leaching experiments indicate the true heterogeneous nature of the catalysis.
