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Topic Review
Heterometal Grafted Metalla-ynes and Poly(metalla-ynes)
Metalla-ynes and poly(metalla-ynes) have emerged as unique molecular scaffolds with fascinating structural features and intriguing photo-luminescence (PL) properties. Their rigid-rod conducting backbone with tunable photo-physical properties has generated immense research interests for the design and development of application-oriented functional materials.
  • 430
  • 05 Nov 2021
Topic Review
Heterogeneous Electroreduction of CO2 on Copper-Based Catalysts
Facing greenhouse effects and the rapid exhaustion of fossil fuel, CO2 electrochemical reduction presents a promising method of environmental protection and energy transformation. Low onset potential, large current density, high faradaic efficiency (FE), and long-time stability are required for industrial production, due to economic costs and energy consumption. Copper is one of the few metals that can reduce CO2 to hydrocarbons and alcohols with decent efficiency, and copper-based catalysts have received much attention. The uniqueness of Cu as a CO2RR electrocatalyst is explained by the fact that it is the only metal that has negative adsorption energy for *CO and positive adsorption energy for *H.
  • 1.0K
  • 18 Aug 2022
Topic Review
Heterogeneous Catalysts in the Reductive Amination of Alcohols
The synthesis of primary amines via the reductive amination of alcohols involves a hydrogen-borrowing or hydrogen-transfer mechanism, which consists of three main steps: alcohol hydroxyl dehydrogenation, carbonyl imidization, and imine hydrogenation. Heterogeneous catalysts are widely used for this reaction because of their high performance and amenability to separation and reuse.
  • 376
  • 18 Oct 2023
Topic Review
Heterogeneous Catalysts Based on Hypercrosslinked Polystyreneand
Platform chemicals, also known as chemical building blocks, are substances that serve as starting materials for the synthesis of various value-added products, which find a wide range of applications. These chemicals are the key ingredients for many fine and specialty chemicals. Most of the transformations of platform chemicals are catalytic processes, which should meet the requirements of sustainable chemistry: to be not toxic for humans, to be safe for the environment, and to allow multiple reuses of catalytic materials. Hypercrosslinked polymers are already widely applied in industry as excellent (ad)sorbents. Their use for the synthesis of heterogeneous catalysts is a relatively new but dynamically developing area. A new class of heterogeneous catalysts based on nanoparticles of catalytically active metals stabilized in a polymer matrix of hypercrosslinked polystyrene (HPS) are provided, their synthesis, properties, and application to produce several platform chemicals from renewable raw materials. Some transformations of platform chemicals into compounds with high added value are addressed and multiple perspectives are discussed.
  • 208
  • 03 Jan 2024
Topic Review
Heterogeneous Catalysts
Nanomaterials are significant carriers for enzymes in heterogeneous biocatalysis.  Large amounts of the active phase can be immobilized due to the large specific surface area.  An interesting approach combines the stabilization of enzymes in ionic liquids and an immobilization of the active phase on a solid support, which allows to biocatalyst's recycling and its application in continuous flow and batch processes. 
  • 514
  • 29 Sep 2021
Topic Review
Heterogeneous Catalysis for Selective Hydrogenation of Oximes
The synthesis of many biologically active compounds is not complete without transforming the carbonyl group into an amino group, carried out by the reaction of nucleophilic substitution with hydroxylamine at the carbonyl carbon atom and further reduction of the C–N and N–O bonds. This method eliminates nitrating agents that exhibit oxidizing properties and may cause undesirable effects on other structural fragments of complex molecules. Selective hydrogenation of oximes over heterogeneous catalysts is still one of the most useful and challenging reactions in synthetic organic chemistry to obtain amines and hydroxylamines since the 1920s when the Adam’s catalyst was first used for this reaction. 
  • 1.0K
  • 28 Dec 2022
Topic Review
Heterogeneous Catalysis for Biomass Valorization and Fine-Chemicals Production
Heterogeneous catalysts are progressively expanding their field of application, from high-throughput reactions for traditional industrial chemistry with production volumes reaching millions of tons per year, a sector in which they are key players, to more niche applications for the production of fine chemicals. These novel applications require a progressive utilization reduction of fossil feedstocks, in favor of renewable ones. Biomasses are the most accessible source of organic precursors, having as advantage their low cost and even distribution across the globe. Unfortunately, they are intrinsically inhomogeneous in nature and their efficient exploitation requires novel catalysts.
  • 622
  • 17 Dec 2021
Topic Review
Heterogeneous Applications of Iron Complexes with Nitrogen-Containing Ligands
Iron complexes are particularly interesting as catalyst systems over the other transition metals (including noble metals) due to iron’s high natural abundance and mediation in important biological processes, therefore making them non-toxic, cost-effective, and biocompatible. Both homogeneous and heterogeneous catalysis mediated by iron as a transition metal have found applications in many industries, including oxidation, C-C bond formation, hydrocarboxylation and dehydration, hydrogenation and reduction reactions of low molecular weight molecules.
  • 230
  • 12 Dec 2023
Topic Review
Heteroelement Analogues of Benzoxaborole
Heteroelement analogues of benzoxaboroles constitute an interesting class of boracyclic compounds and may offer the opportunity for various applications while retaining high stability arising from the presence of a strong B-O bond in the ring structure. The replacement of a carbon atom in the boracycle or an adjacent benzene ring with a heteroatom may result in a significant change of structural behaviour. Moreover,  physicochemical properties, including solubility, lipophilicity, hydrolytic stability, boron Lewis acidity, and others, can be modified. The aim of this review is to highlight several emerging groups of boracyclic systems which comprise various heteroelement atoms such as another boron, silicon, tin, nitrogen, phosphorus, and iodine. The information on synthesis and properties of such systems is complemented by presentation of their practical potential encompassing especially organic synthesis and catalysis as as medicinal chemistry. 
  • 629
  • 22 Sep 2021
Topic Review
Heterocyclic Crown Ethers
Crown ethers are heterocyclic compounds present as cyclic oligomers in their simple form. These are extremely versatile compounds exhibiting higher binding affinity towards metal ions, including s-block and transition metal ions. For example, 18-crown-6 has a cavity that fits the size of 4f transition metal ions and has reflected exceptional attraction for complexation with the lanthanide ions.
  • 1.5K
  • 27 Jan 2022
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