Functionalized Multi-Walled Carbon Nanotubes (f-MWCNT) as Highly Efficient and Reusable Heterogeneous Catalysts for the Synthesis of Acridinedione Derivatives
16 Aug 2016-Vol. 1, Iss: 13, pp 3861-3865
TL;DR: In this article, carboxylic acid groups were immobilized onto carbon nanotubes and their catalytic properties were examined for the first time for the synthesis of acridinedione derivatives, opening new paths in the investigation of catalysis and their comparison with carbon-based materials.
Abstract: Addressed herein, carboxylic acid groups were immobilized onto carbon nanotubes and their catalytic properties were examined for the first time for the synthesis of acridinedione derivatives, opening new paths in the investigation of catalysis and their comparison with carbon-based materials. An efficient methodology for the synthesis of acridinedione derivatives has been achieved by one-pot, multi-component condensation of dimedone, substitute aromatic aldehydes, various aromatic amines and, in the presence of the easily available, inexpensive, and nontoxic f-MWCNTs as versatile biodegradable catalysts. At this method, f-MWCNTs carrying simple carboxylic acid functionalities catalyze the model reaction in ethanol providing the product in a quantitative yield. This highly monodisperse catalyst is one of the most efficient catalysts which gives the highest yield of products in the shortest time. Its high-yield efficiency, clean, eco-friendly, simple work-up procedure, and easy purification are regarded to be the main advantages of this method. The synthesized compounds are characterized using spectroscopic (IR, 1H-NMR, 13C-NMR and HRMS) techniques.
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TL;DR: In this paper, high effective and stable palladium nanoparticles (Pd NPs) supported on graphene oxide (GO) were synthesized, characterized and applied for dehydrogenation of dimethylamine-borane (DMAB) using the ultrasonic reduction method in the presence of oleylamine and GO as support matrices at room temperature.
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TL;DR: In this paper, a highly effective and monodisperse Pt/L@rGO nanocatalysts were successfully synthesized by using different types of ligands and the impact of ligand on catalytic activity of the prepared nanomaterials have been examined for methanol oxidation.
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TL;DR: In this paper, the thiocarbamide-functionalized graphene oxide (TC@GO) supported rhodium/platinum nanoparticles (RhPt/TNM@GO NPs) have been synthesized as promising catalysts for the Knoevenagel condensation to benzylidenemalononitrile derivatives of aryl aldehydes.
Abstract: Functionalization of the graphene provides various possibilities to improve the use of the graphene and to provide more chemical conversion to the graphene. In order to enhance its chemical and physical properties, the graphite which is mainly functionalized with heteroatom-based functional groups is followed intensively, but often results in the inoculation of heteroatoms as various functional groups. Here we show that the graphene oxide can be mainly functionalized with a single species of sulfur and can be reduced to form a graphene which is functionalized with monothiol at the same time. By the help of thiocarbamide-functionalized graphene oxide (TC@GO) the monodisperse rhodium/platinum nanoparticles (RhPt/TC@GO NPs) have been synthesized as promising catalysts for the Knoevenagel condensation to benzylidenemalononitrile derivatives of aryl aldehydes. The monodisperse RhPt/TC@GO NPs have been prepared via a facile method. The novel thiocarbamide-functionalized graphene oxide (TC@GO) supported rhodium/platinum nanoparticles (RhPt/TC@GO NPs) are identified by characterization techniques such as the Raman spectroscopy, high resolution transmission electron microscopy (HRTEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The spectroscopic and morphological studies of the monodisperse RhPt/TNM@GO NPs indicate the highly crystalline form, well dispersity, ultrafine structure and colloidally stable NPs. After fully characterization of prepared nanoparticles, the novel nanocatalysts have been tried for the Knoevenagel condensation to benzylidenemalononitrile derivatives of aryl aldehydes and show excellent catalytic activity and a yield over 99% by the reaction at room temperature within 8–35 min in the presence of malononitrile and derivatives of aldehyde. As a result, the prepared nanocomposites exhibit very good heterogeneous catalyst properties for Knoevenagel condensation reactions.
75 citations
TL;DR: In this paper, a highly efficient, durable and uniformly dispersed activated carbon supported palladium-iridium nanomaterials (Pd-Ir NPs) were reported for the first time as a catalyst in dimethylamine-borane dehydrogenation reaction at the room temperature.
65 citations
TL;DR: In this article, sulfonic acid functionalized multiwalled carbon nanotube (sMWCNT) is explored as a potential inorganic filler as well as a solid acid proton conducting medium to realize a hybrid membrane with Nafion for a polymer electrolyte membrane fuel cell (PEMFC) for low humidity applications.
54 citations
References
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TL;DR: Although not yet providing compelling mechanical strength or electrical or thermal conductivities for many applications, CNT yarns and sheets already have promising performance for applications including supercapacitors, actuators, and lightweight electromagnetic shields.
Abstract: Worldwide commercial interest in carbon nanotubes (CNTs) is reflected in a production capacity that presently exceeds several thousand tons per year. Currently, bulk CNT powders are incorporated in diverse commercial products ranging from rechargeable batteries, automotive parts, and sporting goods to boat hulls and water filters. Advances in CNT synthesis, purification, and chemical modification are enabling integration of CNTs in thin-film electronics and large-area coatings. Although not yet providing compelling mechanical strength or electrical or thermal conductivities for many applications, CNT yarns and sheets already have promising performance for applications including supercapacitors, actuators, and lightweight electromagnetic shields.
4,596 citations
TL;DR: My opinion on why the field of organocatalysis has blossomed so dramatically over the past decade is presented.
Abstract: The use of small organic molecules as catalysts has been known for more than a century. But only in the past decade has organocatalysis become a thriving area of general concepts and widely applicable asymmetric reactions. Here I present my opinion on why the field of organocatalysis has blossomed so dramatically over the past decade.
1,863 citations
TL;DR: In this paper, the van der Waals self-assembly forces and applied electric fields are used to control the growth direction of carbon nanotubes in a patterned growth approach.
Abstract: Synthesis of carbon nanotubes by chemical vapor deposition over patterned catalyst arrays leads to nanotubes grown from specific sites on surfaces. The growth directions of the nanotubes can be controlled by van der Waals self-assembly forces and applied electric fields. The patterned growth approach is feasible with discrete catalytic nanoparticles and scalable on large wafers for massive arrays of novel nanowires. Controlled synthesis of nanotubes opens up exciting opportunities in nanoscience and nanotechnology, including electrical, mechanical, and electromechanical properties and devices, chemical functionalization, surface chemistry and photochemistry, molecular sensors, and interfacing with soft biological systems.
1,732 citations
TL;DR: It is shown here how CNTs formed following Halogenation, followed by Direct Formation on Defect Sites, and the subsequent Encapsulation of Inorganic Substances led to the formation of CNT’s with Metal Nanoparticles.
Abstract: 2.3. Ionic Liquids (ILs) 5374 2.4. Complexation Reactions on Oxidized CNTs 5375 2.5. Halogenation 5376 2.6. Cycloaddition Reactions 5377 2.7. Radical Additions 5379 2.8. Nucleophilic Additions 5381 2.9. Electrophilic Additions 5381 2.10. Electrochemical Modifications 5381 2.11. Plasma-Activation 5381 2.12. Mechanochemical Functionalizations 5382 3. Noncovalent Interactions 5382 3.1. Polynuclear Aromatic Compounds 5382 3.2. Interactions with Other Substances 5384 3.3. Interactions with Biomolecules 5385 4. Endohedral Filling 5386 4.1. Encapsulation of Fullerenes 5386 4.2. Encapsulation of Organic Substances 5387 4.3. Encapsulation of Inorganic Substances 5387 5. Decoration of CNTs with Metal Nanoparticles 5388 5.1. Covalent Linkage 5388 5.2. Direct Formation on Defect Sites 5388 5.3. Electroless Deposition 5388 5.4. Electrodeposition 5389 5.5. Chemical Decoration 5390 5.6. Deposition of Nanoparticles onto CNTs 5391 5.7. π-π Stacking and Electrostatic Interactions 5391 6. Concluding Remarks 5392 7. Acknowledgments 5392 8. References 5392
1,127 citations
TL;DR: This tutorial review will firstly sketch the basic developments in organocatalysis, focussing especially on the use of secondary amines as catalysts for the functionalization of aldehydes and alpha,beta-unsaturated aldeHydes, with emphasis on the mechanisms of the transformations and outline recent trends within central areas of this research topic.
Abstract: The use of secondary amines as asymmetric catalysts in transformations of carbonyl compounds has seen tremendous development in recent years. Going from sporadic reports of selected reactions, aminocatalysis can now be considered as one of the methods of choice for many asymmetric functionalizations of carbonyl compounds—primarily of aldehydes and ketones. These functionalizations have been published at a breathtaking pace over the last few years—during the “golden age” and “gold rush” of organocatalysis. This tutorial review will firstly sketch the basic developments in organocatalysis, focussing especially on the use of secondary amines as catalysts for the functionalization of aldehydes and α,β-unsaturated aldehydes, with emphasis on the mechanisms of the transformations and, secondly, outline recent trends within central areas of this research topic. Lastly, we will present our guesses as to where new developments might take organocatalysis in the years to come.
1,110 citations