scholarly journals Highly Active Pandanus Nanocellulose-Supported Poly(amidoxime) Copper (II) Complex for Ullmann Cross-Coupling Reaction

2020 ◽  
Vol 2 (1) ◽  
pp. 14
Author(s):  
Choong Jian Fui ◽  
Tang Xin Ting ◽  
Mohd Sani Sarjadi ◽  
Md Lutfor Rahman
Keyword(s):  
Transition Metal ◽  
Coupling Reaction ◽  
Transition Metal Catalysts ◽  
High Catalytic Activity ◽  
Radical Initiation ◽  
Organometallic Reagents ◽  
Highly Active ◽  
Earth Abundant ◽  
Free Radical Initiation ◽  
Benzyl Halides

The transition metal-catalyzed chemical transformation of organic electrophiles, and organometallic reagents have turned up as an exceedingly robust synthetic tool. The evolution of transition metal catalysts has attained a stage of civilization that authorizes for an extensive scope of chemical bonds formation partners to be combined efficiently. The applications of Cu-based nanoparticles have received great attention owing to the earth-abundant, low toxicity and inexpensive. Due to these characteristics, copper nanoparticles have generated a great deal of interest especially in the field of catalysis. In this study, poly(acrylonitrile) was synthesized by undergoes free-radical initiation process and followed by Beckmann rearrangement with hydroxylamine solution converted into the poly(amidoxime) ligand and anchored the copper onto poly(amidoxime). Cu(II)@PAM was characterized using different techniques such as FTIR, FESEM, EDX, TEM, TGA, DSC, ICP-OES, and XPS analyses. The Cu(II)@PAM showed high stability and high catalytic activity in a wide variety of electrophilic substituted phenols with substituted aryl/benzyl halides. 0.15 mol%, ±3 mg of Cu(II)@PAM could efficiently promote Ullmann reaction to give the corresponding coupling product up to 99 % yields. The complex was easy separated and recovered from the reaction mixture by simple filtration.

scholarly journals Facet-Dependent Reactivity of Ceria Nanoparticles Exemplified by CeO2-Based Transition Metal Catalysts: A Critical Review

Catalysts ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 452
Author(s):  
Michalis Konsolakis ◽  
Maria Lykaki
Keyword(s):  
Transition Metal ◽  
Co Oxidation ◽  
Critical Review ◽  
Rational Design ◽  
Metal Catalysts ◽  
Co2 Hydrogenation ◽  
Transition Metal Catalysts ◽  
Fine Tuning ◽  
Ceria Nanoparticles ◽  
Highly Active

The rational design and fabrication of highly-active and cost-efficient catalytic materials constitutes the main research pillar in catalysis field. In this context, the fine-tuning of size and shape at the nanometer scale can exert an intense impact not only on the inherent reactivity of catalyst’s counterparts but also on their interfacial interactions; it can also opening up new horizons for the development of highly active and robust materials. The present critical review, focusing mainly on our recent advances on the topic, aims to highlight the pivotal role of shape engineering in catalysis, exemplified by noble metal-free, CeO2-based transition metal catalysts (TMs/CeO2). The underlying mechanism of facet-dependent reactivity is initially discussed. The main implications of ceria nanoparticles’ shape engineering (rods, cubes, and polyhedra) in catalysis are next discussed, on the ground of some of the most pertinent heterogeneous reactions, such as CO2 hydrogenation, CO oxidation, and N2O decomposition. It is clearly revealed that shape functionalization can remarkably affect the intrinsic features and in turn the reactivity of ceria nanoparticles. More importantly, by combining ceria nanoparticles (CeO2 NPs) of specific architecture with various transition metals (e.g., Cu, Fe, Co, and Ni) remarkably active multifunctional composites can be obtained due mainly to the synergistic metalceria interactions. From the practical point of view, novel catalyst formulations with similar or even superior reactivity to that of noble metals can be obtained by co-adjusting the shape and composition of mixed oxides, such as Cu/ceria nanorods for CO oxidation and Ni/ceria nanorods for CO2 hydrogenation. The conclusions derived could provide the design principles of earth-abundant metal oxide catalysts for various real-life environmental and energy applications.

Solvent-Free Assembled Fe-Chitosan Chelates Derived N-Doped Carbon Layer-Encapsulated Fe/Fe3C for ORR and OER

NANO ◽  
2020 ◽  
Vol 15 (06) ◽  
pp. 2050070
Author(s):  
Renxing Huang ◽  
Ying Lei ◽  
Dandan Zhang ◽  
Huaming Xie ◽  
Xingyong Liu ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Transition Metal ◽  
Nitrogen Source ◽  
Small Molecule ◽  
Carbon Layer ◽  
Transition Metal Catalysts ◽  
Solvent Free ◽  
Metal Catalyst ◽  
High Peak Power ◽  
High Catalytic Activity

Carbon encapsulated transition metal catalysts receive extensive attention in electrochemical catalytic oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) due to the unique structure and highly adjustable electronic configuration. Herein, we synthesized 3D porous Active-N-rich graphene-like carbon layer-encapsulated Fe/Fe3C (Fe@NCG) via pyrolysis of a mixture of solvent-free assembled Fe-chitosan chelates and additional small molecule nitrogen source urea, wherein space-confinement effect of chelates suppressed agglomeration of [Formula: see text] ions and small molecule nitrogen source facilitated regulation of N configurations. The optimized catalyst Fe@NCG shows remarkable ORR/OER bifunctional catalytic activity with a half-wave potential of 0.86 V for ORR and a moderate potential difference of 0.85 V in alkaline medium. Comparative studies revealed that Active-N-rich carbon layer and inner well-dispersed Fe/Fe3C nanoparticles and the favorable interface structures between them were responsible for high catalytic activity. Excitingly, the assembled zinc-air battery with Fe@NCG catalysts exhibits a high open-circuit potential (1.45 V), extremely high peak power density (204.50[Formula: see text][Formula: see text] and energy density (814.70[Formula: see text]Wh[Formula: see text][Formula: see text]) as well as robust charge–discharge durability, surpassing those of noble metal catalyst. This proposed simple and universal strategy can also be extended to synthesize carbon encapsulated other transition metal electrocatalysts.

Transition Metal-Free Strategies for the Synthesis of C-1 Aryl Substituted Tetrahydroisoquinolines

Synthesis ◽  
2021 ◽  
Author(s):  
Pushpinder Singh ◽  
Aanchal Batra ◽  
Kamal Nain Singh ◽  
Mritunjay Mritunjay
Keyword(s):  
Transition Metal ◽  
Oxidative Coupling ◽  
Metal Salt ◽  
Toxic Metal ◽  
Transition Metal Catalysts ◽  
Bioactive Molecules ◽  
Chemical Waste ◽  
Organometallic Reagents ◽  
Metal Free ◽  
Synthetic Drugs

1-Aryl-1,2,3,4-tetrahydroisoquinolines are important structural motifs and are widely found in bioactive molecules, pharmaceutical and synthetic drugs. In view of increasing environmental awareness, the development of transition metal-free strategies for the synthesis of these compounds is highly desirable. Metal-free oxidative coupling and lithiation methodologies have emerged as effective tools in this area as they exclude the use of transition metal catalysts and help in reducing unwanted and toxic metal based chemical waste in the environment. This review highlights the recent advances in direct arylation of tetrahydroisoquinolines for the synthesis of title compounds in the absence of metal salt. Also, the emphasis has been put on the mechanistic considerations of these reactions. 1 Introduction 2 Arylation of tetrahydroisoquinolines via oxidative coupling 2.1 Arylation using Grignard reagents 2.2 Arylation using other organometallic reagents 2.3 Arylation using aryl organoboranes or arenes 3 Arylation of tetrahydroisoquinolines via lithiation 3.1 Intermolecular arylation 3.2 Intramolecular arylation 4 Conclusions and Outlook

scholarly journals Water oxidation using earth-abundant transition metal catalysts: opportunities and challenges

2016 ◽  
Vol 45 (37) ◽  
pp. 14421-14461 ◽  
Author(s):  
Markus D. Kärkäs ◽  
Björn Åkermark
Keyword(s):  
Transition Metal ◽  
Solar Energy ◽  
Water Oxidation ◽  
Metal Catalysts ◽  
Transition Metal Catalysts ◽  
Oxidation Catalysts ◽  
Fuel Conversion ◽  
Earth Abundant ◽  
Vital Component ◽  
Conversion Technologies

Catalysts for the oxidation of water are a vital component of solar energy to fuel conversion technologies. This Perspective summarizes recent advances in the field of designing homogeneous water oxidation catalysts (WOCs) based on Mn, Fe, Co and Cu.

Coupling of arylboronic acids with benzyl halides or mesylates without adding transition metal catalysts

Tetrahedron ◽  
2016 ◽  
Vol 72 (49) ◽  
pp. 8022-8030 ◽  
Author(s):  
Guojiao Wu ◽  
Shuai Xu ◽  
Yifan Deng ◽  
Chaoqiang Wu ◽  
Xia Zhao ◽  
...  
Keyword(s):  
Transition Metal ◽  
Metal Catalysts ◽  
Transition Metal Catalysts ◽  
Arylboronic Acids ◽  
Benzyl Halides
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