An immobilised Co(ii) and Ni(ii) Schiff base magnetic nanocatalyst via a click reaction: a greener approach for alcohol oxidation

2015 ◽  
Vol 39 (6) ◽  
pp. 4933-4938 ◽  
Author(s):  
Pooja B. Bhat ◽  
Badekai Ramachandra Bhat
Keyword(s):  
Schiff Base ◽  
Strong Interaction ◽  
Click Reaction ◽  
Alcohol Oxidation ◽  
Magnetic Nanocatalyst ◽  
System P ◽  
Oxidation Of Alcohols

A Schiff base immobilised magnetic nanocatalyst synthesized via copper catalysed alkyne azide cycloaddition (CuAAC) exhibited a strong interaction and improved yielding for oxidation of alcohols in a solventless system.

Mono-, tri- and polynuclear copper(ii) complexes of Schiff-base ligands: synthesis, characterization and catalytic activity towards alcohol oxidation

2017 ◽  
Vol 41 (13) ◽  
pp. 5696-5706 ◽  
Author(s):  
Aradhita Bhattacharjee ◽  
Shibashis Halder ◽  
Koushik Ghosh ◽  
Corrado Rizzoli ◽  
Partha Roy
Keyword(s):  
Schiff Base ◽  
Catalytic Activity ◽  
Alcohol Oxidation ◽  
Polynuclear Complex ◽  
Schiff Base Ligands ◽  
Oxidation Of Alcohols

A mononuclear copper(ii) complex acts as a superior catalyst compared to a tri- or polynuclear complex towards oxidation of alcohols to the corresponding aldehydes.

scholarly journals A Study of Catalytic Oxidation of a Library of C2 to C4 Alcohols in the Presence of Nanogold

Nanomaterials ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 442
Author(s):  
Maciej Kapkowski ◽  
Anna Niemczyk-Wojdyla ◽  
Piotr Bartczak ◽  
Monika Pyrkosz Bulska ◽  
Kamila Gajcy ◽  
...  
Keyword(s):  
Organic Chemistry ◽  
Green Chemistry ◽  
Alcohol Oxidation ◽  
Catalytic Performance ◽  
Toxic Chemicals ◽  
Wide Scope ◽  
Catalytic Potential ◽  
Green Oxidation ◽  
Oxidation Of Alcohols ◽  
Different Levels

The classical stoichiometric oxidation of alcohols is an important tool in contemporary organic chemistry. However, it still requires huge modifications in order to comply with the principles of green chemistry. The use of toxic chemicals, hazardous organic solvents, and the large amounts of toxic wastes that result from the reactions are a few examples of the problems that must be solved. Nanogold alone or conjugated with palladium were supported on different carriers (SiO2, C) and investigated in order to evaluate their catalytic potential for environmentally friendly alcohol oxidation under solvent-free and base-free conditions in the presence H2O2 as a clean oxidant. We tested different levels of Au loading (0.1–1.2% wt.) and different active catalytic site forms (monometallic Au or bimetallic Au–Pd sites). This provided new insights on how the structure of the Au-dispersions affected their catalytic performance. Importantly, the examination of the catalytic performance of the resulting catalysts was oriented toward a broad scope of alcohols, including those that are the most resistant to oxidation—the primary aliphatic alcohols. Surprisingly, the studies proved that Au/SiO2 at a level of Au loading as low as 0.1% wt. appeared to be efficient and prospective catalytic system for the green oxidation of alcohol. Most importantly, the results revealed that 0.1% Au/SiO2 might be the catalyst of choice with a wide scope of utility in the green oxidation of various structurally different alcohols as well as the non-activated aliphatic ones.

The effects of molecular structure and functional group of a rodlike Schiff base mesogen on blue phase stabilization in a chiral system

2019 ◽  
Vol 43 (4) ◽  
pp. 1743-1756
Author(s):  
Chiung-Cheng Huang ◽  
Yu-Chang Huang ◽  
Wei-Cheng Hsieh ◽  
Yen-Jung Chen ◽  
Shi-Kai Jiang ◽  
...  
Keyword(s):  
Molecular Structure ◽  
Schiff Base ◽  
Functional Group ◽  
Phase Stabilization ◽  
System P ◽  
Blue Phase ◽  
Chiral Dopants ◽  
Chiral System

A wider blue phase (BP) range can be induced easily when two difluoro substituted and racemic rodlike Schiff base mesogens are doped with the appropriate concentration of chiral dopants S811 or ISO(6OBA)2.

scholarly journals Biomimetic Cu/Nitroxyl Catalyst Systems for Selective Alcohol Oxidation

Catalysts ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 395 ◽  
Author(s):  
Lindie Marais ◽  
Andrew John Swarts
Keyword(s):  
Active Sites ◽  
Alcohol Oxidation ◽  
Galactose Oxidase ◽  
Co Catalyst ◽  
Co Catalysts ◽  
Mechanistic Pathway ◽  
Oxidation Of Alcohols ◽  
Catalyst Systems ◽  
Carbonyl Products

The oxidation of alcohols to the corresponding carbonyl products is an important organic transformation and the products are used in a variety of applications. The development of catalytic methods for selective alcohol oxidation have garnered significant attention in an attempt to find a more sustainable method without any limitations. Copper, in combination with 2,2,6,6-tetramethyl-1-piperidine N-oxyl (TEMPO) and supported by organic ligands, have emerged as the most effective catalysts for selective alcohol oxidation and these catalyst systems are frequently compared to galactose oxidase (GOase). The efficiency of GOase has led to extensive research to mimic the active sites of these enzymes, leading to a variety of Cu/TEMPO· catalyst systems being reported over the years. The mechanistic pathway by which Cu/TEMPO· catalyst systems operate has been investigated by several research groups, which led to partially contradicting mechanistic description. Due to the disadvantages and limitations of employing TEMPO· as co-catalyst, alternative nitroxyl radicals or in situ formed radicals, as co-catalysts, have been successfully evaluated in alcohol oxidation. Herein we discuss the development and mechanistic elucidation of Cu/TEMPO· catalyst systems as biomimetic alcohol oxidation catalysts.

scholarly journals Aroylhydrazone Schiff Base Derived Cu(II) and V(V) Complexes: Efficient Catalysts towards Neat Microwave-Assisted Oxidation of Alcohols

2020 ◽  
Vol 21 (8) ◽  
pp. 2832
Author(s):  
Manas Sutradhar ◽  
Tannistha Roy Barman ◽  
Armando J. L. Pombeiro ◽  
Luísa M. D. R. S. Martins
Keyword(s):  
Schiff Base ◽  
Aliphatic Alcohol ◽  
Cinnamyl Alcohol ◽  
X Ray Diffraction ◽  
Reaction Conditions ◽  
Benzyl Alcohols ◽  
X Ray ◽  
Microwave Assisted ◽  
Tert Butyl Hydroperoxide ◽  
Oxidation Of Alcohols

A new hexa-nuclear Cu(II) complex [Cu3(μ2-1κNO2,2κNO2-L)(μ-Cl)2(Cl)(MeOH)(DMF)2]2 (1), where H4L = N′1,N′2-bis(2-hydroxybenzylidene)oxalohydrazide, was synthesized and fully characterized by IR spectroscopy, ESI-MS, elemental analysis, and single crystal X-ray diffraction. Complex 1 and the dinuclear oxidovanadium(V) one [{VO(OEt)(EtOH)}2(1κNO2,2κNO2-L)]·2H2O (2) were used as catalyst precursors for the neat oxidation of primary (cinnamyl alcohol) and secondary (1-phenyl ethanol, benzhydrol) benzyl alcohols and of the secondary aliphatic alcohol cyclohexanol, under microwave irradiation using tert-butyl hydroperoxide (TBHP) as oxidant. Oxidations proceed via radical mechanisms. The copper(II) compound 1 exhibited higher catalytic activity than the vanadium(V) complex 2 for all the tested alcohol substrates. The highest conversion was found for 1-phenylethanol, yielding 95.3% of acetophenone in the presence of 1 and in solvent and promoter-free conditions. This new Cu(II) complex was found to exhibit higher activity under milder reaction conditions than the reported aroylhydrazone Cu(II) analogues.

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