The catalytic acceptorless dehydrogenation (CAD) is an attractive synthetic route to unsaturated compounds because of its high atomice fficiency.H erew e report electrochemical acceptorless dehydrogenation of N-heterocycles to obtain quinoline or indole derivatives using metal-organic layer (MOL) catalyst. MOL is the twodimensional version of metal-organic frameworks (MOF), and it can be constructed on conductive multi-walled carbon nanotubes via facile solvothermal synthesis to overcome the conductivity constraint for MOFs in electrocatalysis. TEMPO-OPO 3 2À was incorporated into the system through al igand exchange with capping formate on the MOL surface to serve as the active catalytic centers. The hybrid catalyst is efficient in the organic conversion and can be readily recycled and reused.The catalytic acceptorless dehydrogenation (CAD) of N-heterocycles is an atomically efficient way to synthesize quinoline and indole rings, [1] whicha re widely found in pharmaceuticals and bioactive molecules. [2] Moreover,t hese N-heterocycles are also proposed asH 2 carriers for liquid organic H 2 storage. [3] Conventional dehydrogenations require oxidants or sacrificial hydrogen acceptors, which usually produce byproducts such as toxic metal salts. [4] Recent development of acceptorless dehydrogenation produces H 2 to avoid the use of an oxidant. A number of catalysts based on noble metalss uch as iridium, [5] palladium, [6] platinum [6b, 7] and ruthenium, [8] and nom-noble metals such as iron, [9] cobalt [10] and nickel, [11] and organic borane compounds [12] are active for this transformation. However,m ost of the above catalysts are homogeneous complexes that requires catalyst removal after the reaction, increasing the overall cost of synthesis. Therefore, it is still of interest to perform dehydrogenation in the absence of these homogeneous catalysts, especiallym etal complexes, to avoid the tedious separation step or the contamination of the product. Electrosyn-[a] L.
A three-dimensional (3D) metal-organic framework constructed from unprecedented Zn9O2(OH)2(pyz)12 (pyz = pyrazolate) clusters and Ni(salen)-derived linkers was reported. The MOF exhibits high catalytic activity for CO2 cycloaddition reactions with excellent...
Sodium samarium borate Na 3 Sm(BO 3 ) 2 , was prepared by a flux method and structurally characterized by single-crystal structure analysis for the first time. The results show that it crystallizes in the monoclinic system P2 1 /n, with a = 6.5667(3) Å, b = 8.7675(4) Å, c = 10.1850(5), β = 90.86 • , V = 586.32(5) Å 3 and Z = 4. The structure contains NaO 7 , NaO 6 , NaO 5 , SmO 8 , and BO 3 units, which are interconnected via corner-or edge-sharing O atoms into a three-dimensional structure. The excitation spectra, emission spectra, decay time, and Commission International de l'Éclairage (CIE) chromaticity index of Na 3 Sm(BO 3 ) 2 were studied. Under near light excitation (406 nm), the powdered Na 3 Sm(BO 3 ) 2 shows the orange-red emission, which originates from the 4 G 5/2 → 6 H 9/2 and 4 G 5/2 → 6 H 7/2 transformation of Sm 3+ ion.
This study reports the four-dimensional commensurately modulated structure of ZnNb2O6 using superspace formalism for aperiodic structures considering the modulation vector, q = 1/3 b*.
A series of orthophosphates NaLn(PO) (Ln = lanthanoids) have for a long time been known as good luminescent materials, yet their crystal structures have not been studied in full detail. In this work, compound NaLa(PO) was prepared using molten salt (flux) method and for the first time was structurally determined on X-ray single-crystal diffraction data. Interestingly, it crystallizes in the four-dimensional incommensurately modulated structure with orthorhombic superspace group Pca2(0β0)000 and modulation wave vector q = 0.387b*. Furthermore, to evaluate the potentiality of NaLa(PO) to be used as a luminescent host material, 5 mol % Eu, Tb, and Dy doped phosphors were prepared, respectively. The excitation spectra, emission spectra, decay time, quantum efficiency, and the color purity of prepared phosphors, NaLaEu(PO), NaLaTb(PO), and NaLaDy(PO), were studied.
Electrochemical CO2 reduction (ECR) into value-added
multicarbon products is a promising approach for a carbon-neutral
economy. Heterogeneous molecular catalysts consist of atomic-precise,
controllable active sites with the potential to improve catalytic
activity by ligand design and engineering, yet most reported molecular
ECR catalysts do not exhibit multicarbon product selectivity. Herein,
we report the use of a copper–supramolecular pair as a crystalline
molecular catalyst to promote the formation of multicarbon products.
A combination of experimental and theoretical studies reveal that
the paired Cu sites work collaboratively to activate the CO2 substrate and facilitate the coupling of adsorbed CO species although
they are not bonded or bridged directly. The van der Waals interactions
between the substrate and the secondary coordination sphere also play
a crucial role in multicarbon product selectivity.
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