Synthesis, crystal structure and catalytic activity of the guanidinium cation directed nickel(ii)-containing open Wells–Dawson 19-tungstodiarsenate(iii) [{Ni(H2O)4}2{Na(H2O)}As2W19O67(H2O)]9−

RSC Advances ◽  
2015 ◽  
Vol 5 (32) ◽  
pp. 25273-25278 ◽  
Author(s):  
Mukesh Kumar Saini ◽  
Rakesh Gupta ◽  
Surendra Singh ◽  
Firasat Hussain

Guanidinium directed open Wells–Dawson type [{Ni(H2O)4}2{Na(H2O)}As2W19O67(H2O)]9− polyanion 1 has been synthesized on reacting nickel chloride and trilacunary Na9[B-α-AsW9O33] in aqueous solution (pH ∼ 5.8), in presence of pyridine-2,6-dicarboxylic acid.

2015 ◽  
Vol 71 (11) ◽  
pp. 1384-1387
Author(s):  
Marwen Chouri ◽  
Habib Boughzala

The title compound bis(1,4-diazoniabicyclo[2.2.2]octane) di-μ-chlorido-bis[tetrachloridobismuthate(III)] dihydrate, (C6H14N2)2[Bi2Cl10]·2H2O, was obtained by slow evaporation at room temperature of a hydrochloric aqueous solution (pH = 1) containing bismuth(III) nitrate and 1,4-diazabicyclo[2.2.2]octane (DABCO) in a 1:2 molar ratio. The structure displays a two-dimensional arrangement parallel to (100) of isolated [Bi2Cl10]4−bioctahedra (site symmetry -1) separated by layers of organic 1,4-diazoniabicyclo[2.2.2]octane dications [(DABCOH2)2+] and water molecules. O—H...Cl, N—H...O and N—H...Cl hydrogen bonds lead to additional cohesion of the structure.


Author(s):  
Zhi Xiang Ji ◽  
Peng Fei Li

A new Cd(II) coordination polymer, {[Cd3(L)2(DMF)2(H2O)2]·H2O}n (H2L = 1,3-bisbenzyl-2-imidazolidine-4,5-dicarboxylic acid) was synthesized by one-pot synthesis method from 1,3-bisbenzyl-2-imidazolidine-4,5-dicarboxylic acid, NaOH, DMF, and Cd(NO3)2·4H2O. Its structure was determined by elemental analysis and single crystal X-ray diffraction. Structural analysis shows that three Cd(II) ions are all six-coordinated with four oxygen atoms of four 1,3-bisbenzyl-2-imidazolidine-4,5-dicarboxylate ligands and two O atoms from two DMF molecules (Cd1) or two oxygen atoms of two coordinated H2O molecules (Cd2 and Cd3) to form an octahedral coordination geometry. The Cd(II) coordination polymer displays a 1D chained structure by the bridging carboxylate groups from 1,3-bisbenzyl-2-imidazolidine-4,5-dicarboxylate ligands. The conversion of benzaldehyde is 90.9%, which is 40~50% higher than those of the other three aldehydes (4-methylbenzaldehyde, p-methoxybenzaldehyde and 3-chlorobenzaldehyde), so the Cd(II) coordination polymer catalyst shows better catalytic activity for the coupling reaction of benzaldehyde, phenylacetylene, and piperidine than the other three aldehydes. Copyright © 2018 BCREC Group. All rights reservedReceived: 25th April 2017; Revised: 11st September 2017; Accepted: 1st November 2017; Available online: 11st June 2018; Published regularly: 1st August 2018How to Cite: Ji, Z.X., Li, P.F. (2018). Crystal Structure and Catalytic Activity of A Novel Cd(II) Coordination Polymer Formed by Dicarboxylic Ligand. Bulletin of Chemical Reaction Engineering & Catalysis, 13 (2): 220-226 (doi:10.9767/bcrec.13.2.1178.220-226) 


Author(s):  
Jiwei Zhang ◽  
Jingjing Xu ◽  
Shuaixia Liu ◽  
Baoxiang Gu ◽  
Feng Chen ◽  
...  

Background: Coal gangue was used as a catalyst in heterogeneous Fenton process for the degradation of azo dye and phenol. The influencing factors, such as solution pH gangue concentration and hydrogen peroxide dosage were investigated, and the reaction mechanism between coal gangue and hydrogen peroxide was also discussed. Methods: Experimental results showed that coal gangue has the ability to activate hydrogen peroxide to degrade environmental pollutants in aqueous solution. Under optimal conditions, after 60 minutes of treatment, more than 90.57% of reactive red dye was removed, and the removal efficiency of Chemical Oxygen Demand (COD) up to 72.83%. Results: Both hydroxyl radical and superoxide radical anion participated in the degradation of organic pollutant but hydroxyl radical predominated. Stability tests for coal gangue were also carried out via the continuous degradation experiment and ion leakage analysis. After five times continuous degradation, dye removal rate decreased slightly and the leached Fe was still at very low level (2.24-3.02 mg L-1). The results of Scanning Electron Microscope (SEM), energy dispersive X-Ray Spectrometer (EDS) and X-Ray Powder Diffraction (XRD) indicated that coal gangue catalyst is stable after five times continuous reuse. Conclusion: The progress in this research suggested that coal gangue is a potential nature catalyst for the efficient degradation of organic pollutant in water and wastewater via the Fenton reaction.


1979 ◽  
Vol 44 (4) ◽  
pp. 1015-1022 ◽  
Author(s):  
Viliam Múčka

The catalytic properties of two-component catalyst nickel oxide-cadmium oxide with the proportions of the components covering the whole composition region 0-100% were examined by studying the decomposition of hydrogen peroxide in aqueous solution on it. In the range 0-25 mol.% CdO, cadmium oxide is found to affect infavourably the ability of nickel oxide to chemisorb oxygen. The amount of the chemisorbed oxygen increases several times on gamma irradiation of the samples. The effect of cadmium oxide on the catalytic activity of the system shows up in fresh samples only indirectly via the changed amount of the oxygen chemisorbed. In older samples the initial catalytic activity of the system is changed, which can be explained based on the concept of bivalent catalytic centres in terms of the co-action of the catalytic centres of the two oxides, which are in equilibrium. The irradiation of the system under study speeds up the processes leading to the establishing of this equilibrium which is thermally very stable, and results in a substantial increase of the catalytic activity of the samples investigated.


Author(s):  
Sajid Hussain ◽  
Eleonora Aneggi ◽  
Daniele Goi

AbstractInnovations in water technology are needed to solve challenges of climate change, resource shortages, emerging contaminants, urbanization, sustainable development and demographic changes. In particular, conventional techniques of wastewater treatment are limited by the presence of poorly biodegradable organic matter. Alternatively, recent Fenton, Fenton-like and hybrid processes appear successful for cleaning of different types of liquid wastewaters. Here, we review the application of metallic catalyst-H2O2 systems in the heterogeneous Fenton process. Each metallic catalyst-H2O2 system has unique redox properties due to metal oxidation state. Solution pH is a major influencing factor. Catalysts made of iron and cerium form stable complexes with oxidation products and H2O2, thus resulting in reduced activities. Copper forms transitory complexes with oxidation products, but copper catalytic activity is restored during the reaction. Silver and manganese do not form complexes. The catalyst performance for degradation and mineralization decreases in the order: manganese, copper, iron, silver, cerium, yet the easiness of practical application decreases in the order: copper, manganese, iron, silver, cerium.


CrystEngComm ◽  
2021 ◽  
Author(s):  
Anna A Mukhacheva ◽  
Vladislav Komarov ◽  
Vasily Kokovkin ◽  
Alexander S. Novikov ◽  
Pavel A Abramov ◽  
...  

The [{(C6H6)Ru}2W8O30(OH)2]6– hybrid (organometallic-POM) anion was used as a pH-tunable building block to create special conditions for realizing π-π interactions in the crystal structure. Changing pH of aqueous solution of...


1995 ◽  
Vol 270 (52) ◽  
pp. 31414
Author(s):  
Sunghee Kim ◽  
Sthanam V.L. Narayana ◽  
John E. Volanakis

2014 ◽  
Vol 70 (11) ◽  
pp. 1054-1056 ◽  
Author(s):  
Qiang Li ◽  
Hui-Ting Wang

A new cadmium dicyanamide complex, poly[tetramethylphosphonium [μ-chlorido-di-μ-dicyanamido-κ4N1:N5-cadmium(II)]], [(CH3)4P][Cd(NCNCN)2Cl], was synthesized by the reaction of tetramethylphosphonium chloride, cadmium nitrate tetrahydrate and sodium dicyanamide in aqueous solution. In the crystal structure, each CdIIatom is octahedrally coordinated by four terminal N atoms from four anionic dicyanamide (dca) ligands and by two chloride ligands. The dicyanamide ligands play two different roles in the building up of the structure; one role results in the formation of [Cd(dca)Cl]2building blocks, while the other links the building blocks into a three-dimensional structure. The anionic framework exhibits a solvent-accessible void of 673.8 Å3, amounting to 47.44% of the total unit-cell volume. The cavities in the network are occupied by pairs of tetramethylphosphonium cations.


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