scholarly journals Mixed-ligand complexes of paddlewheel dinuclear molybdenum as hydrodehalogenation catalysts for polyhaloalkanes

2015 ◽  
Vol 6 (6) ◽  
pp. 3434-3439 ◽  
Author(s):  
Hayato Tsurugi ◽  
Akio Hayakawa ◽  
Shun Kando ◽  
Yoshitaka Sugino ◽  
Kazushi Mashima
Keyword(s):  
Catalytic Activity ◽  
Mixed Ligand ◽  
Mixed Ligand Complexes ◽  
High Catalytic Activity

A mixed-ligated dimolybdenum complex Mo2(OAc)2[CH(NAr)2]2 in combination with 1-methyl-3,6-bis(trimethylsilyl)-1,4-cyclohexadiene and nBu4NCl exhibited high catalytic activity for hydrodehalogenation reactions.

Catalytic activity of metal chelates and mixed-ligand complexes in the neutral pH region. II. Copper-histidine

1970 ◽  
Vol 92 (4) ◽  
pp. 822-826 ◽  
Author(s):  
Vijay Sharan. Sharma ◽  
Jack. Schubert ◽  
Helen B. Brooks ◽  
F. Sicilio
Keyword(s):  
Catalytic Activity ◽  
Metal Chelates ◽  
Mixed Ligand ◽  
Mixed Ligand Complexes ◽  
Neutral Ph ◽  
Region Ii

Enhanced catalytic activity of low-Pt content nanocatalysts supported on hollow carbon spheres for the ORR in alkaline media

MRS Advances ◽  
2020 ◽  
Vol 5 (57-58) ◽  
pp. 2961-2972
Author(s):  
P.C. Meléndez-González ◽  
E. Garza-Duran ◽  
J.C. Martínez-Loyola ◽  
P. Quintana-Owen ◽  
I.L. Alonso-Lemus ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Anion Exchange ◽  
Average Particle Size ◽  
Synthesis Method ◽  
Alkaline Media ◽  
High Catalytic Activity ◽  
Average Particle ◽  
Carbon Spheres ◽  
Hollow Carbon ◽  
Hollow Carbon Spheres

In this work, low-Pt content nanocatalysts (≈ 5 wt. %) supported on Hollow Carbon Spheres (HCS) were synthesized by two routes: i) colloidal conventional polyol, and ii) surfactant-free Bromide Anion Exchange (BAE). The nanocatalysts were labelled as Pt/HCS-P and Pt/HCS-B for polyol and BAE, respectively. The physicochemical characterization of the nanocatalysts showed that by following both methods, a good control of chemical composition was achieved, obtaining in addition well dispersed nanoparticles of less than 3 nm TEM average particle size (d) on the HCS. Pt/HCS-B contained more Pt0 species than Pt/HCS-P, an effect of the synthesis method. In addition, the structure of the HCS remains more ordered after BAE synthesis, compared to polyol. Regarding the catalytic activity for the Oxygen Reduction Reaction (ORR) in 0.5 M KOH, Pt/HCS-P and Pt/HCS-B showed a similar performance in terms of current density (j) at 0.9 V vs. RHE than the benchmark commercial 20 wt. % Pt/C. However, Pt/HCS-P and Pt/HCS-B demonstrated a 6 and 5-fold increase in mass catalytic activity compared to Pt/C, respectively. A positive effect of the high specific surface area of the HCS and its interactions with metal nanoparticles and electrolyte, which promoted the mass transfer, increased the performance of Pt/HCS-P and Pt/HCS-B. The high catalytic activity showed by Pt/HCS-B and Pt/HCS-P for the ORR, even with a low-Pt content, make them promising cathode nanocatalysts for Anion Exchange Membrane Fuel Cells (AEMFC).

Ordered Intermetallic Nanoparticles with High Catalytic Activity Prepared by an Electrochemically Induced Phase Transformation

2019 ◽  
Author(s):  
Du Sun ◽  
yunfei wang ◽  
Kenneth Livi ◽  
chuhong wang ◽  
ruichun luo ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Diffusion Mechanism ◽  
Reduction Reaction ◽  
Atomic Scale ◽  
High Catalytic Activity ◽  
Ambient Conditions ◽  
Magnetic Devices ◽  
Disordered Alloys ◽  
Ordered Intermetallic ◽  
Intermetallic Nanoparticles

<div> <p>The synthesis of alloys with long range atomic scale ordering (ordered intermetallics) is an emerging field of nanochemistry. Ordered intermetallic nanoparticles are useful for a wide variety of applications such as catalysis, superconductors, and magnetic devices. However, the preparation of nanostructured ordered intermetallics is challenging in comparison to disordered alloys, hindering progress in materials development. We report a process for converting colloidally synthesized ordered intermetallic PdBi<sub>2</sub> to ordered intermetallic Pd<sub>3</sub>Bi nanoparticles under ambient conditions by an electrochemically induced phase transition. The low melting point of PdBi<sub>2</sub> corresponds to low vacancy formation energies which enables the facile removal of the Bi from the surface, while simultaneously enabling interdiffusion of the constituent atoms via a vacancy diffusion mechanism under ambient conditions. The resulting phase-converted ordered intermetallic Pd<sub>3</sub>Bi exhibits 11x and 3.5x higher mass activty and high methanol tolerance for the oxygen reduction reaction compared to Pt/C and Pd/C, respectively,which is the highest reported for a Pd-based catalyst, to the best of our knowledge. These results establish a key development in the synthesis of noble metal rich ordered intermetallic phases with high catalytic activity, and sets forth guidelines for the design of ordered intermetallic compounds under ambient conditions.</p> </div>

Nickel (II) and oxovanadium (IV) complexes supported on MCM-41 mesoporous and their application in catalytic selective sulfide and thiol oxidation

2020 ◽  
Vol 23 ◽  
Author(s):  
Mohsen Nikoorazm ◽  
Maryam Khanmoradi ◽  
Masoumeh Sayadian
Keyword(s):  
Catalytic Activity ◽  
Room Temperature ◽  
Sol Gel ◽  
Reaction Times ◽  
Significant Loss ◽  
Spectral Studies ◽  
High Catalytic Activity ◽  
Catalytic Systems ◽  
Solvent Free Conditions ◽  
Mcm 41

Introduction:: MCM-41 was synthesized using the sol-gel method. Then two new transition metal complexes of Nickel (II) and Vanadium (IV), were synthesized by immobilization of adenine (6-aminopurine) into MCM-41 mesoporous. The compounds have been characterized by XRD, TGA, SEM, AAS and FT-IR spectral studies. Using these catalysts provided an efficient and enantioselective procedure for oxidation of sulfides to sulfoxides and oxidative coupling of thiols to their corresponding disulfides using hydrogen peroxide at room temperature. Materials and Methods:: To a solution of sulfide or thiol (1 mmol) and H2O2 (5 mmol), a determined amount of the catalyst was added. The reaction mixture was stirred at room temperature for the specific time under solvent free conditions. The progress of the reaction was monitored by TLC using n-hexane: acetone (8:2). Afterwards, the catalyst was removed from the reaction mixture by centrifugation and, then, washed with dichloromethane in order to give the pure products. Results:: All the products were obtained in excellent yields and short reaction times indicating the high activity of the synthesized catalysts. Besides, the catalysts can be recovered and reused for several runs without significant loss in their catalytic activity. Conclusion:: These catalytic systems furnish the products very quickly with excellent yields and VO-6AP-MCM-41 shows high catalytic activity compared to Ni-6AP-MCM-41.

Mixed ligand-metal Complexes of 2-(butan-2-ylidene) hydrazinecarbothioamide- Synthesis, Characterization, Computer Aided Drug Character Evaluation and in vitro Biological Activity Assessment

2019 ◽  
Vol 15 ◽  
Author(s):  
Tahmeena Khan ◽  
Rumana Ahmad ◽  
Iqbal Azad ◽  
Saman Raza ◽  
Seema Joshi ◽  
...  
Keyword(s):  
Molecular Docking ◽  
Metal Complexes ◽  
Condensation Reaction ◽  
Dose Range ◽  
Biological Significance ◽  
Mixed Ligand ◽  
Binding Energies ◽  
Mixed Ligand Complexes ◽  
E Coli ◽  
Topo Ii

Background: Mixed ligand-metal complexes are efficient chelating agents because of flexible donor ability. Mixed ligand complexes containing hetero atoms sulphur, nitrogen and oxygen have been probed for their biological significance. Objective: Nine mixed ligand-metal complexes of 2-(butan-2-ylidene) hydrazinecarbothioamide (2-butanone thiosemicarbazone) and pyridine, bipyridine or 2-picoline as co-ligands were synthesized with Cu, Fe and Zn. The complexes were tested against MDA-MB231 (MDA) and A549 cell lines. Antibacterial activity was tested against S. aureus and E. coli. The drug character of the complexes was evaluated on several parameters viz. physicochemical properties, bioactivity scores, toxicity assessment and absorption, distribution, metabolism, excretion and toxicity (ADMET) profile assessment using various automated softwares. Molecular docking of the complexes was also performed with two target proteins. Method and Results: The mixed ligand-metal complexes were synthesized by condensation reaction for 4-5 h. The characterization was done by elemental analysis, 1H-NMR, FT-IR, molar conductance and UV spectroscopies. Molecular docking was performed against ribonucleotide reductase (RR) and topoisomerase II (topo II). [Cu(C5H11N3S)(py)2(CH3COO)2], [Zn(C5H11N3S)(bpy)(SO4)] and [Zn(C5H11N3S)(2-pic)2(SO4)] displayed the lowest binding energies with respect to RR. Against topo II [Cu(C5H11N3S)(py)2(CH3COO)2], [Cu(C5H11N3S)(bpy)(CH3COO)2] and [Zn(C5H11N3S)(2-pic)2(SO4)] had the lowest energies. The druglikness assessment was done using Leadlikeness and Lipinski’s rules. Against topo II [Cu(C5H11N3S)(py)2(CH3COO)2], [Cu(C5H11N3S)(bpy)(CH3COO)2] and [Zn(C5H11N3S)(2-pic)2(SO4)] had the lowest energies. Not more than two violations were obtained in case of each filtering rule showing drug like character of the mixed ligand complexes. Several of the complexes exhibited positive bioactivity scores and almost all the complexes were predicted to be safe with no hazardous effects. All the complexes were predicted to have no mutagenic character as shown by the Ames test [Zn(C5H11N3S)(py)2(SO4)] showed potential activity against MDA. [Co(C5H11N3S(bpy)(Cl)2] was also active against MDA. [Cu(C5H11N3S)(2-pic)2(CH3COO)2] also showed 27.6% cell viability at 100 µM against MDA. Against A549 [Co(C5H11N3S)(py)2(Cl)2], [Cu(C5H11N3S)(py)2(CH3COO)2] and [Co(C5H11N3S(bpy)(Cl)2] were active. [Co(C5H11N3S)(bpy)(Cl)2] and [Cu(C5H11N3S)(2-pic)2(CH3COO)2] were active against S. aureus. [Co(C5H11N3S)(2-pic)2(Cl)2] and [Zn(C5H11N3S)(2-pic)2(SO4)] were active at lower concentrations against S.aureus. Against E. coli, [Zn(C5H11N3S)(2-pic)2(SO4)] showed activity at 18-20mg dose range.

Interaction of ditertiary phosphines with phenyl- and 1-naphthyldithiocarbamatonickel(II)

1985 ◽  
Vol 50 (6) ◽  
pp. 1383-1390
Author(s):  
Aref A. M. Aly ◽  
Ahmed A. Mohamed ◽  
Mahmoud A. Mousa ◽  
Mohamed El-Shabasy
Keyword(s):  
Thermal Analysis ◽  
Powder Diffraction ◽  
Spin Structure ◽  
Magnetic Measurements ◽  
Mixed Ligand ◽  
Mixed Ligand Complexes ◽  
X Ray ◽  
Square Planar

The synthesis of the following mixed ligand complexes is reported: [Ni(phdtc)2(dpm)2], [Ni(phdtc)2(dpe)2], [Ni(phdtc)2(dpp)3], [Ni(1-naphdtc)2(dpm)2], [Ni(1-naphdtc)2], and [Ni(1-naphdtc)2(dpp)2], where phdtc = PhNHCSS-, 1-naphdtc = 1-NaPhNHCSS-, dpm = Ph2PCH2PPh2, dpe = Ph2P(CH2)2PPh2, and dpp = Ph2P(CH2)3PPh2. The complexes are characterised by microanalysis, IR and UV-Vis spectra, magnetic measurements, conductivity, X-ray powder diffraction, and thermal analysis. All the mixed ligand complexes are diamagnetic, and thus a square-planar or square-pyramidal (low-spin) structure was proposed for the present complexes.

Mechanisms of methane decomposition and carbon species oxidation on the Pr0.42Sr0.6Co0.2Fe0.7Nb0.1O3−σ electrode with high catalytic activity

2015 ◽  
Vol 3 (45) ◽  
pp. 22816-22823 ◽  
Author(s):  
Peng Zhang ◽  
Guoqing Guan ◽  
Deni S. Khaerudini ◽  
Xiaogang Hao ◽  
Chunfeng Xue ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Carbon Deposition ◽  
Methane Decomposition ◽  
High Catalytic Activity ◽  
Carbon Species

Carbon deposition characteristics on PSCFN and Ni–YSZ due to thermal CH4 decomposition are investigated by using TPR technique.

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