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Articles de revues sur le sujet « Metal Mediated Catalysis »

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Auteur : Grafiati
Publié le 7 septembre 2023

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1

Leven, Matthias, Jörg M. Neudörfl et Bernd Goldfuss. « Metal-mediated aminocatalysis provides mild conditions : Enantioselective Michael addition mediated by primary amino catalysts and alkali-metal ions ». Beilstein Journal of Organic Chemistry 9 (23 janvier 2013) : 155–65. http://dx.doi.org/10.3762/bjoc.9.18.

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Four catalysts based on new amides of chiral 1,2-diamines and 2-sulfobenzoic acid have been developed. The alkali-metal salts of these betaine-like amides are able to form imines with enones, which are activated by Lewis acid interaction for nucleophilic attack by 4-hydroxycoumarin. The addition of 4-hydroxycoumarin to enones gives ee’s up to 83% and almost quantitative yields in many cases. This novel type of catalysis provides an effective alternative to conventional primary amino catalysis were strong acid additives are essential components.
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2

Bennett, Jeffrey A., Bradley A. Davis, Kirill Efimenko, Jan Genzer et Milad Abolhasani. « Network-supported, metal-mediated catalysis : progress and perspective ». Reaction Chemistry & ; Engineering 5, no 10 (2020) : 1892–902. http://dx.doi.org/10.1039/d0re00229a.

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3

Astruc, D. « Organometallic chemistry at the nanoscale. Dendrimers for redox processes and catalysis ». Pure and Applied Chemistry 75, no 4 (1 janvier 2003) : 461–81. http://dx.doi.org/10.1351/pac200375040461.

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An overview of the metal-mediated synthesis and use of nanosized metallodendrimers is given with emphasis on electron-transfer processes (molecular batteries consisting in dendrimers decorated with a large number of equivalent redox-active centers) and catalytic reactions (electron-transfer-chain catalytic synthesis of dendrimers decorated with ruthenium carbonyl clusters, redox catalysis of nitrate and nitrite electroreduction in water by star-shape hexanuclear catalysts).
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Pagliaro, Mario, Cristina Della Pina, Francesco Mauriello et Rosaria Ciriminna. « Catalysis with Silver : From Complexes and Nanoparticles to MORALs and Single-Atom Catalysts ». Catalysts 10, no 11 (19 novembre 2020) : 1343. http://dx.doi.org/10.3390/catal10111343.

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Silver catalysis has a rich and versatile chemistry now expanding from processes mediated by silver complexes and silver nanoparticles to transformations catalyzed by silver metal organic alloys and single-atom catalysts. Focusing on selected recent advances, we identify the key advantages offered by these highly selective heterogeneous catalysts. We conclude by offering seven research and educational guidelines aimed at further progressing the field of new generation silver-based catalytic materials.
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5

Kirsebom, L. A. « RNase P RNA-mediated catalysis ». Biochemical Society Transactions 30, no 6 (1 novembre 2002) : 1153–58. http://dx.doi.org/10.1042/bst0301153.

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The endoribonuclease RNase P is involved in the processing of tRNA precursors to generate mature 5′ termini. The catalytic activity of RNase P is associated with an RNA, RNase P RNA. A specific interaction between the 3′ end of the substrate and RNase P RNA, to form an RNase P RNA-substrate complex, is referred to as the ‘73–294-interaction’. This interaction has an important role for efficient and correct cleavage to occur. Here our understanding of the contribution of the 73–294-interaction and metal ions, with respect to efficient and correct cleavage in RNase P RNA-mediated catalysis, will be discussed.
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Mummadi, Suresh, et Clemens Krempner. « Triphenylborane in Metal-Free Catalysis ». Molecules 28, no 3 (31 janvier 2023) : 1340. http://dx.doi.org/10.3390/molecules28031340.

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The development and application of new organoboron reagents as Lewis acids in synthesis and metal-free catalysis have dramatically expanded over the past 20 years. In this context, we will show the recent uses of the simple and relatively weak Lewis acid BPh3—discovered 100 years ago—as a metal-free catalyst for various organic transformations. The first part will highlight catalytic applications in polymer synthesis such as the copolymerization of epoxides with CO2, isocyanate, and organic anhydrides to various polycarbonate copolymers and controlled diblock copolymers as well as alternating polyurethanes. This is followed by a discussion of BPh3 as a Lewis acid component in the frustrated Lewis pair (FLP) mediated cleavage of hydrogen and hydrogenation catalysis. In addition, BPh3-catalyzed reductive N-methylations and C-methylations with CO2 and silane to value-added organic products will be covered as well along with BPh3-catalyzed cycloadditions and insertion reactions. Collectively, this mini-review showcases the underexplored potential of commercially available BPh3 in metal-free catalysis.
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7

Subramanian, Palaniappan, Dalila Meziane, Robert Wojcieszak, Franck Dumeignil, Rabah Boukherroub et Sabine Szunerits. « Plasmon-Induced Electrocatalysis with Multi-Component Nanostructures ». Materials 12, no 1 (24 décembre 2018) : 43. http://dx.doi.org/10.3390/ma12010043.

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Noble metal nanostructures are exceptional light absorbing systems, in which electron–hole pairs can be formed and used as “hot” charge carriers for catalytic applications. The main goal of the emerging field of plasmon-induced catalysis is to design a novel way of finely tuning the activity and selectivity of heterogeneous catalysts. The designed strategies for the preparation of plasmonic nanomaterials for catalytic systems are highly crucial to achieve improvement in the performance of targeted catalytic reactions and processes. While there is a growing number of composite materials for photochemical processes-mediated by hot charge carriers, the reports on plasmon-enhanced electrochemical catalysis and their investigated reactions are still scarce. This review provides a brief overview of the current understanding of the charge flow within plasmon-enhanced electrochemically active nanostructures and their synthetic methods. It is intended to shed light on the recent progress achieved in the synthesis of multi-component nanostructures, in particular for the plasmon-mediated electrocatalysis of major fuel-forming and fuel cell reactions.
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8

Wang, Bing, Junjie Zhang, Yun Xue, Yuliang Chong, Dongdong Zhao, Hu Cheng, Liangliang Tian et Jinliang Zhuang. « Enhanced Catalytic Activity of TEMPO-Mediated Aerobic Oxidation of Alcohols via Redox-Active Metal–Organic Framework Nodes ». Molecules 28, no 2 (6 janvier 2023) : 593. http://dx.doi.org/10.3390/molecules28020593.

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Metal–organic frameworks (MOFs) are outstanding platforms for heterogeneous catalysis due to their tunable pore size, huge surface area, large porosity, and potential active sites. The design and synthesis of MOF/organocatalyst co-catalytic systems have attracted considerable interest owing to their high catalytic activity, low toxicity, and mild reaction conditions. Herein, we reported the synthesis of a bifunctional TEMPO-IsoNTA organocatalyst featuring a pyridyl group as an anchoring site and a TEMPO radical as a catalytic active site. By using the topologically isomorphic structures of MIL-101(Fe) and MIL-101(Cr) as co-catalysts, these MOF/TEMPO-IsoNTA systems enable the efficient aerobic oxidation of various alcohols to their corresponding aldehydes or ketones under mild conditions. Notably, the MIL-101(Fe)/TEMPO-IsoNTA system exhibits superior catalytic activity, thanks to their redox-active FeIII-oxo nodes, which facilitate the regeneration of TEMPO-IsoNTA. Our research not only solves the problem of potential heavy metal contamination in the TEMPO-based homogeneous catalytic system, but also enriches the understanding of synergism of MOFs/organocatalysts.
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Welin, Eric R., Chip Le, Daniela M. Arias-Rotondo, James K. McCusker et David W. C. MacMillan. « Photosensitized, energy transfer-mediated organometallic catalysis through electronically excited nickel(II) ». Science 355, no 6323 (26 janvier 2017) : 380–85. http://dx.doi.org/10.1126/science.aal2490.

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Transition metal catalysis has traditionally relied on organometallic complexes that can cycle through a series of ground-state oxidation levels to achieve a series of discrete yet fundamental fragment-coupling steps. The viability of excited-state organometallic catalysis via direct photoexcitation has been demonstrated. Although the utility of triplet sensitization by energy transfer has long been known as a powerful activation mode in organic photochemistry, it is surprising to recognize that photosensitization mechanisms to access excited-state organometallic catalysts have lagged far behind. Here, we demonstrate excited-state organometallic catalysis via such an activation pathway: Energy transfer from an iridium sensitizer produces an excited-state nickel complex that couples aryl halides with carboxylic acids. Detailed mechanistic studies confirm the role of photosensitization via energy transfer.
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10

Vanni, Matteo, Maria Caporali, Manuel Serrano-Ruiz et Maurizio Peruzzini. « Catalysis Mediated by 2D Black Phosphorus Either Pristine or Decorated with Transition Metals Species ». Surfaces 3, no 2 (1 avril 2020) : 132–67. http://dx.doi.org/10.3390/surfaces3020012.

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Among the novel class of mono-elemental two-dimensional (2D) materials, termed Xenes, phosphorene is emerging as a great promise for its peculiar chemical and physical properties. This review collects a selection of the recent breakthroughs that are related to the application of phosphorene in catalysis and electrocatalysis. Noteworthy, thanks to its intrinsic Lewis basic character, pristine phosphorene turned out to be more efficient and more selective than other non-metal catalysts, in chemical processes as the electroreduction of nitrogen to ammonia or the alkylation of nucleophiles with esters. Once functionalized with transition metals nanoparticles (Co, Ni, Pd, Pt, Ag, Au), its catalytic activity has been evaluated in several processes, mainly hydrogen and oxygen evolution reactions. Under visible light irradiation, it has shown a great improvement of the activity, demonstrating high potential as a photocatalyst.
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Harinath, Adimulam, Jayeeta Bhattacharjee, Alok Sarkar et Tarun K. Panda. « Alkali metal complex-mediated ring-opening polymerization of rac-LA, ε-caprolactone, and δ-valerolactone ». New Journal of Chemistry 43, no 23 (2019) : 8882–91. http://dx.doi.org/10.1039/c9nj01130g.

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12

Hilinski, Michael, Shea Johnson et Logan Combee. « Organocatalytic Atom-Transfer C(sp3)–H Oxidation ». Synlett 29, no 18 (27 juin 2018) : 2331–36. http://dx.doi.org/10.1055/s-0037-1610432.

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Predictably site-selective catalytic methods for intermolecular C(sp3)–H hydroxylation and amination hold great promise for the synthesis and late-stage modification of complex molecules. Transition-metal catalysis has been the most common approach for early investigations of this type of reaction. In comparison, there are far fewer ­reports of organocatalytic methods for direct oxygen or nitrogen insertion into C–H bonds. Herein, we provide an overview of early efforts in this area, with particular emphasis on our own recent development of an iminium salt that catalyzes both oxygen and nitrogen insertion.1 Introduction2 Background: C–H Oxidation Capabilities of Heterocyclic Oxidants3 Oxaziridine-Mediated Catalytic Hydroxylation4 Dioxirane-Mediated Catalytic Hydroxylation5 Iminium Salt Catalysis of Hydroxylation and Amination6 Conclusion and Outlook
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13

Roychowdhury-Saha, M. « Extraordinary rates of transition metal ion-mediated ribozyme catalysis ». RNA 12, no 10 (6 septembre 2006) : 1846–52. http://dx.doi.org/10.1261/rna.128906.

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14

Li, Xiao-Na, Xiu-Ping Zou et Sheng-Gui He. « Metal-mediated catalysis in the gas phase : A review ». Chinese Journal of Catalysis 38, no 9 (septembre 2017) : 1515–27. http://dx.doi.org/10.1016/s1872-2067(17)62782-7.

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15

Liu, Ning, Chun Liu, Xiaofeng Rao et Zilin Jin. « ChemInform Abstract : Poly(ethylene Glycol) in Metal-Mediated Catalysis ». ChemInform 44, no 14 (20 mars 2013) : no. http://dx.doi.org/10.1002/chin.201314254.

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Martín, Cristina del Mar García, José Ignacio Hernández García, Sebastián Bonardd et David Díaz Díaz. « Lignin-Based Catalysts for C–C Bond-Forming Reactions ». Molecules 28, no 8 (16 avril 2023) : 3513. http://dx.doi.org/10.3390/molecules28083513.

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Carbon–carbon (C–C) bond formation is the key reaction in organic synthesis to construct the carbon framework of organic molecules. The continuous shift of science and technology toward eco-friendly and sustainable resources and processes has stimulated the development of catalytic processes for C–C bond formation based on the use of renewable resources. In this context, and among other biopolymer-based materials, lignin has attracted scientific attention in the field of catalysis during the last decade, either through its acid form or as a support for metal ions and metal nanoparticles that drive the catalytic activity. Its heterogeneous nature, as well as its facile preparation and low cost, provide competitive advantages over other homogeneous catalysts. In this review, we have summarized a variety of C–C formation reactions, such as condensations, Michael additions of indoles, and Pd-mediated cross-coupling reactions that were successfully carried out in the presence of lignin-based catalysts. These examples also involve the successful recovery and reuse of the catalyst after the reaction.
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Wang, Xin, Ming-Hui Zhu et Wen-Bo Liu. « Potassium Alkoxide/Disilane-Mediated Dehalogenative Deuteration ». Synlett 30, no 09 (19 mars 2019) : 1003–7. http://dx.doi.org/10.1055/s-0037-1610699.

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Deuterated compounds are of great importance in chemistry and pharmaceuticals. Reductive dehalogenation is one of the most useful methods to incorporate deuterium into molecules. This article briefly discusses the historical development of dehalogenative deuteration reactions that involve transition-metal catalysis, radical halogen abstraction, alkali-metal reductive deuteration, and the recently developed potassium methoxide/hexamethyldisilane-mediated dehalogenation of aryl halides.
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18

Willcox, Dominic R., et Stephen P. Thomas. « Group 13 exchange and transborylation in catalysis ». Beilstein Journal of Organic Chemistry 19 (21 mars 2023) : 325–48. http://dx.doi.org/10.3762/bjoc.19.28.

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Catalysis is dominated by the use of rare and potentially toxic transition metals. The main group offers a potentially sustainable alternative for catalysis, due to the generally higher abundance and lower toxicity of these elements. Group 13 elements have a rich catalogue of stoichiometric addition reactions to unsaturated bonds but cannot undergo the redox chemistry which underpins transition-metal catalysis. Group 13 exchange reactions transfer one or more groups from one group 13 element to another, through σ-bond metathesis; where boron is both of the group 13 elements, this is termed transborylation. These redox-neutral processes are increasingly being used to render traditionally stoichiometric group 13-mediated processes catalytic and develop new catalytic processes, examples of which are the focus of this review.
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Nghiem, Tai-Lam, Deniz Coban, Stefanie Tjaberings et André H. Gröschel. « Recent Advances in the Synthesis and Application of Polymer Compartments for Catalysis ». Polymers 12, no 10 (24 septembre 2020) : 2190. http://dx.doi.org/10.3390/polym12102190.

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Catalysis is one of the most important processes in nature, science, and technology, that enables the energy efficient synthesis of essential organic compounds, pharmaceutically active substances, and molecular energy sources. In nature, catalytic reactions typically occur in aqueous environments involving multiple catalytic sites. To prevent the deactivation of catalysts in water or avoid unwanted cross-reactions, catalysts are often site-isolated in nanopockets or separately stored in compartments. These concepts have inspired the design of a range of synthetic nanoreactors that allow otherwise unfeasible catalytic reactions in aqueous environments. Since the field of nanoreactors is evolving rapidly, we here summarize—from a personal perspective—prominent and recent examples for polymer nanoreactors with emphasis on their synthesis and their ability to catalyze reactions in dispersion. Examples comprise the incorporation of catalytic sites into hydrophobic nanodomains of single chain polymer nanoparticles, molecular polymer nanoparticles, and block copolymer micelles and vesicles. We focus on catalytic reactions mediated by transition metal and organocatalysts, and the separate storage of multiple catalysts for one-pot cascade reactions. Efforts devoted to the field of nanoreactors are relevant for catalytic chemistry and nanotechnology, as well as the synthesis of pharmaceutical and natural compounds. Optimized nanoreactors will aid in the development of more potent catalytic systems for green and fast reaction sequences contributing to sustainable chemistry by reducing waste of solvents, reagents, and energy.
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Liang, Hao, Bi-Jian Liu, Bo Tang, Shi-Cheng Zhu, Shen Li, Xing-Zu Ge, Jia-Le Li, Jun-Rong Zhu et Fang-Xing Xiao. « Atomically Precise Metal Nanocluster-Mediated Photocatalysis ». ACS Catalysis 12, no 7 (23 mars 2022) : 4216–26. http://dx.doi.org/10.1021/acscatal.2c00841.

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21

Ahmad, Dalla Tiezza et Orian. « In Silico Acetylene [2+2+2] Cycloadditions Catalyzed by Rh/Cr Indenyl Fragments ». Catalysts 9, no 8 (9 août 2019) : 679. http://dx.doi.org/10.3390/catal9080679.

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Metal-catalyzed alkyne [2+2+2] cycloadditions provide a variety of substantial aromatic compounds of interest in the chemical and pharmaceutical industries. Herein, the mechanistic aspects of the acetylene [2+2+2] cycloaddition mediated by bimetallic half-sandwich catalysts [Cr(CO)3IndRh] (Ind = (C9H7)−, indenyl anion) are investigated. A detailed exploration of the potential energy surfaces (PESs) was carried out to identify the intermediates and transition states, using a relativistic density functional theory (DFT) approach. For comparison, monometallic parent systems, i.e., CpRh (Cp = (C5H5)−, cyclopentadienyl anion) and IndRh, were included in the analysis. The active center is the rhodium nucleus, where the [2+2+2] cycloaddition occurs. The coordination of the Cr(CO)3 group, which may be in syn or anti conformation, affects the energetics of the catalytic cycle as well as the mechanism. The reaction and activation energies and the turnover frequency (TOF) of the catalytic cycles are rationalized, and, in agreement with the experimental findings, our computational analysis reveals that the presence of the second metal favors the catalysis.
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Liu, Xin, Xin Zhang et Changgong Meng. « Coadsorption Interfered CO Oxidation over Atomically Dispersed Au on h-BN ». Molecules 27, no 11 (5 juin 2022) : 3627. http://dx.doi.org/10.3390/molecules27113627.

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Similar to the metal centers in biocatalysis and homogeneous catalysis, the metal species in single atom catalysts (SACs) are charged, atomically dispersed and stabilized by support and substrate. The reaction condition dependent catalytic performance of SACs has long been realized, but seldom investigated before. We investigated CO oxidation pathways over SACs in reaction conditions using atomically dispersed Au on h-BN (AuBN) as a model with extensive first-principles-based calculations. We demonstrated that the adsorption of reactants, namely CO, O2 and CO2, and their coadsorption with reaction species on AuBN would be condition dependent, leading to various reaction species with different reactivity and impact the CO conversion. Specifically, the revised Langmuir–Hinshelwood pathway with the CO-mediated activation of O2 and dissociation of cyclic peroxide intermediate followed by the Eley–Rideal type reduction is dominant at high temperatures, while the coadsorbed CO-mediated dissociation of peroxide intermediate becomes plausible at low temperatures and high CO partial pressures. Carbonate species would also form in existence of CO2, react with coadsorbed CO and benefit the conversion. The findings highlight the origin of the condition-dependent CO oxidation performance of SACs in detailed conditions and may help to rationalize the current understanding of the superior catalytic performance of SACs.
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Sahoo, Manoj K., Siba P. Midya, Vinod G. Landge et Ekambaram Balaraman. « A unified strategy for silver-, base-, and oxidant-free direct arylation of C–H bonds ». Green Chemistry 19, no 9 (2017) : 2111–17. http://dx.doi.org/10.1039/c6gc03438a.

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An external oxidant-free, base-free direct C–H arylation of anilides by visible-light mediated metal-free photoredox catalysis in tandem with palladium catalysis is described. The reaction operates at room temperature, without a silver-salt activator and additives, and no generation of copious metal waste.
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Roh, Sang Weon, Kyoungmin Choi et Chulbom Lee. « Transition Metal Vinylidene- and Allenylidene-Mediated Catalysis in Organic Synthesis ». Chemical Reviews 119, no 6 (15 février 2019) : 4293–356. http://dx.doi.org/10.1021/acs.chemrev.8b00568.

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Neilson, Bethany M., et Christopher W. Bielawski. « Photoswitchable Metal-Mediated Catalysis : Remotely Tuned Alkene and Alkyne Hydroborations ». Organometallics 32, no 10 (9 mai 2013) : 3121–28. http://dx.doi.org/10.1021/om400348h.

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26

Hammer, Stephan C., Grzegorz Kubik, Ella Watkins, Shan Huang, Hannah Minges et Frances H. Arnold. « Anti-Markovnikov alkene oxidation by metal-oxo–mediated enzyme catalysis ». Science 358, no 6360 (12 octobre 2017) : 215–18. http://dx.doi.org/10.1126/science.aao1482.

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Naskar, Shuvankar, Rweetuparna Guha et Jens Müller. « Metal‐Modified Nucleic Acids : Metal‐Mediated Base Pairs, Triples, and Tetrads ». Angewandte Chemie International Edition 59, no 4 (21 août 2019) : 1397–406. http://dx.doi.org/10.1002/anie.201905913.

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Ollevier, Thierry, Virginie Carreras et Nour Tanbouza. « The Power of Iron Catalysis in Diazo Chemistry ». Synthesis 53, no 01 (15 septembre 2020) : 79–94. http://dx.doi.org/10.1055/s-0040-1707272.

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AbstractThe use of iron catalysis to enable reactions with diazo compounds has emerged as a valuable tool to forge carbon–carbon or carbon–heteroatom bonds. While diazo compounds are often encountered with toxic and expensive metal catalysts, such as Rh, Ru, Pd, Ir, and Cu, a resurgence of Fe catalysis has been observed. This short review will showcase and highlight the recent advances in iron-mediated reactions of diazo compounds.1 Introduction2 Insertion Reactions2.1 Insertion into B–H Bonds2.2 Insertion into Si–H Bonds2.3 Insertion into N–H Bonds2.4 Insertion into S–H bonds3 Ylide Formation and Subsequent Reactions3.1 Doyle–Kirmse Rearrangement3.2 [1,2]-Stevens and Sommelet–Hauser Rearrangements3.3 Olefination Reactions3.4 Cycloaddition Reactions3.5 gem-Difluoroalkenylation4 Three-Component Reactions5 Miscellaneous6 Conclusion
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SOLANO, Francisco, Celia JIMÉNEZ-CERVANTES, José H. MARTÍNEZ-LIARTE, José C. GARCÍA-BORRÓN, José R. JARA et José A. LOZANO. « Molecular mechanism for catalysis by a new zinc-enzyme, dopachrome tautomerase ». Biochemical Journal 313, no 2 (15 janvier 1996) : 447–53. http://dx.doi.org/10.1042/bj3130447.

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Dopachrome tautomerase (DCT; EC 5.3.3.12) catalyses the conversion of L-dopachrome into 5,6-dihydroxyindole-2-carboxylic acid in the mammalian eumelanogenic biosynthetic pathway. This enzyme, also named TRP2, belongs to a family of three metalloenzymes termed the tyrosinase-related proteins (TRPs). It is well known that tyrosinase has copper in its active site. However, the nature of the metal ion in the active site of DCT is under discussion. Whereas theoretical predictions based on similarity between the protein sequences of the TRPs suggest the presence of copper, the different inhibition pattern of DCT with some metal chelators compared with that of tyrosinase suggests that the nature of the metal ion could differ. Direct estimations of the metal content in purified DCT preparations show the presence of around 1.5 Zn atoms/molecule and the absence of copper. Apoenzyme preparation by treatment of DCT with cyanide or o-phenanthroline followed by reconstitution experiments of tautomerase activity in the presence of different ions confirmed that the metal cofactor for the DCT active site is zinc. Our results are consistent with Zn2+ chelation by the highly conserved histidine residues homologous to the histidines at the classical copper-binding sites in tyrosinase. This finding accounts for the reaction catalysed by DCT, i.e. a tautomerization, versus the copper-mediated oxidations catalysed by tyrosinase. Based on the predicted tetrahedrical co-ordination of the zinc ions in the enzyme active site, a molecular mechanism for the catalysis of L-dopachrome tautomerization is proposed. From the present data, the existence of additional ligands for metal ions other than zinc in the DCT molecule, such as the proposed cysteine iron-binding sites, cannot be completely ruled out. However, if such sites exist, they could be subsidiary binding sites, whose function would be likely to stabilize the protein.
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Xia, Younan, Kyle D. Gilroy, Hsin-Chieh Peng et Xiaohu Xia. « Seed-Mediated Growth of Colloidal Metal Nanocrystals ». Angewandte Chemie International Edition 56, no 1 (14 décembre 2016) : 60–95. http://dx.doi.org/10.1002/anie.201604731.

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Armstrong, David R., William Clegg, Sophie H. Dale, Eva Hevia, Lorna M. Hogg, Gordon W. Honeyman et Robert E. Mulvey. « Directedmeta-Metalation Using Alkali-Metal-Mediated Zincation ». Angewandte Chemie International Edition 45, no 23 (2 juin 2006) : 3775–78. http://dx.doi.org/10.1002/anie.200600720.

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Maridevaru, Madappa C., Andrea Sorrentino, Belqasem Aljafari et Sambandam Anandan. « Composites for Aqueous-Mediated Heterogeneously Catalyzed Degradation and Mineralization of Water Pollutants on TiO2—A Review ». Journal of Composites Science 6, no 11 (13 novembre 2022) : 350. http://dx.doi.org/10.3390/jcs6110350.

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Wastewater incorporates a wide range of organic toxins, which have an adverse impact on the health of humans and other living things. In recent years, nanotechnology has promoted effective strategies for the photodegradation of industrial organic toxins and tenacious medical contaminants present in wastewater. Advanced composites based on photocatalysts can provide promising solutions for environmental cleanup without generating hazardous byproducts, because they promote the complete oxidation of contaminants. This survey article recaps the essentials of heterogeneous catalysis. Among the major players in heterogeneous catalysis, the metal oxide catalyst (e.g., TiO2) groups cover photocatalysis of water toxins such as dyes, harmful organic molecules, and pharmaceutical contamination. The reasons for the proposal of TiO2 as an active filler for heterogeneous photocatalysts include its superior surface area, significant activity for distinct oxidation and reduction reactions at low temperatures and pressures, effective interaction with metal supports, and chemical stability. Because of the aforementioned features, heterogeneous TiO2 catalysts have a lot of potential in photocatalyst applications, and they can be improved even further by doping them with anionic or cationic dopants.
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Yu, Liang, Ziwei Li, Chen Hua, Kaimin Chen et Xuhong Guo. « Temperature Responsive Diblock Polymer Brushes as Nanoreactors for Silver Nanoparticles Catalysis ». Polymers 15, no 8 (19 avril 2023) : 1932. http://dx.doi.org/10.3390/polym15081932.

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Metal nanoparticles are widely used in catalysis. Loading metal nanoparticles into polymer brushes has aroused wide attention, but regulation of catalytic performance still needs to be improved. The novel diblock polymer brushes, polystyrene@sodium polystyrene sulfonate-b-poly (N-isopropylacrylamide) (PSV@PSS-b-PNIPA) and PSV@PNIPA-b-PSS with reversed block sequence, were prepared by surface initiated photoiniferter-mediated polymerization (SI-PIMP) and used as nanoreactors to load silver nanoparticles (AgNPs). The block sequence caused the difference of conformation and further affected the catalytic performance. PSV@PNIPA-b-PSS@Ag was found to be able to control the amount of AgNPs exposed to external reactant of 4-nitrophenol at different temperatures to achieve regulation of the reaction rate due to the hydrogen bonds and further physical crosslinking between PNIPA and PSS.
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Duchemin, Nicolas, Erica Benedetti, Lucas Bethge, Stefan Vonhoff, Sven Klussmann, Jean-Jacques Vasseur, Janine Cossy, Michael Smietana et Stellios Arseniyadis. « Expanding biohybrid-mediated asymmetric catalysis into the realm of RNA ». Chemical Communications 52, no 55 (2016) : 8604–7. http://dx.doi.org/10.1039/c6cc03540j.

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Li, Pingfan. « Sulfur-Mediated Reactions through Sulfonium Salts and Ylides ». Synlett 32, no 13 (5 mars 2021) : 1275–80. http://dx.doi.org/10.1055/a-1409-0906.

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AbstractThis Account discusses several new reaction methods developed in our group that utilize sulfur-mediated reactions through sulfonium salts and ylides, highlighting the interplay of rational design and serendipity. Our initial goal was to convert aliphatic C–H bonds into C–C bonds site-selectively, and without the use of transition-metal catalysts. While a proof-of-concept has been achieved, this target is far from being ideally realized. The unexpected discovery of an anti-Markovnikov rearrangement and subsequent studies on difunctionalization of alkynes were much more straightforward, and eventually led to the new possibility of asymmetric N–H insertion of sulfonium ylides through Brønsted acid catalysis.1 Introduction2 Allylic/Propargylic C–H Functionalization3 Anti-Markovnikov Rearrangement4 Difunctionalization of Alkynes5 Asymmetric N–H Insertion of Sulfonium Ylides6 Conclusion
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Melone, Lucio, et Carlo Punta. « Metal-free aerobic oxidations mediated by N-hydroxyphthalimide. A concise review ». Beilstein Journal of Organic Chemistry 9 (2 juillet 2013) : 1296–310. http://dx.doi.org/10.3762/bjoc.9.146.

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Since the beginning of the century, N-hydroxyphthalimide and related compounds have been revealed to be efficient organocatalysts for free-radical processes and have found ample application in promoting the aerobic oxidation of a wide range of organic substrates. When combined with different co-catalysts, they are activated to the corresponding N-oxyl radical species and become able to promote radical chains, involving molecular oxygen, directly or indirectly. Most of the examples reported in the literature describe the use of these N-hydroxy derivatives in the presence of transition-metal complexes. However, eco-friendly standards, including the demand for highly selective transformations, impose the development of metal-free processes, especially for large-scale productions, as in the case of the oxygenation of hydrocarbons. For this reason, many efforts have been devoted in the past decade to the design of new protocols for the activation of N-hydroxy imides in the presence of nonmetal initiators. Herein we provide a concise overview of the most significant and successful examples in this field, with the final aim to furnish a useful instrument for all scientists actively involved in the O2-mediated selective oxidation of organic compounds and looking for environmentally safe alternatives to metal catalysis.
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Trost, Barry M., Chuen Chan et Gerd Ruhter. « Metal-mediated approach to enynes ». Journal of the American Chemical Society 109, no 11 (mai 1987) : 3486–87. http://dx.doi.org/10.1021/ja00245a064.

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Fingerhut, Vargas-Caporali, Leyva-Ramírez, Juaristi et Tsogoeva. « Biomimetic Non-Heme Iron-Catalyzed Epoxidation of Challenging Terminal Alkenes Using Aqueous H2O2 as an Environmentally Friendly Oxidant ». Molecules 24, no 17 (1 septembre 2019) : 3182. http://dx.doi.org/10.3390/molecules24173182.

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Catalysis mediated by iron complexes is emerging as an eco-friendly and inexpensive option in comparison to traditional metal catalysis. The epoxidation of alkenes constitutes an attractive application of iron(III) catalysis, in which terminal olefins are challenging substrates. Herein, we describe our study on the design of biomimetic non-heme ligands for the in situ generation of iron(III) complexes and their evaluation as potential catalysts in epoxidation of terminal olefins. Since it is well-known that active sites of oxidases might involve imidazole fragment of histidine, various simple imidazole derivatives (seven compounds) were initially evaluated in order to find the best reaction conditions and to develop, subsequently, more elaborated amino acid-derived peptide-like chiral ligands (10 derivatives) for enantioselective epoxidations.
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Kurup, Sudheer S., et Stanislav Groysman. « Catalytic synthesis of azoarenes via metal-mediated nitrene coupling ». Dalton Transactions 51, no 12 (2022) : 4577–89. http://dx.doi.org/10.1039/d2dt00228k.

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This article summarizes recent findings in the field of transition metal-mediated nitrene coupling catalysis through the lens of mechanistic and structure–activity studies, and highlights unsolved challenges in the field.
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Oloyede, Hammed Olawale, Joseph Anthony Orighomisan Woods, Helmar Görls, Winfried Plass et Abiodun Omokehinde Eseola. « New cobalt(ii) coordination designs and the influence of varying chelate characters, ligand charges and incorporated group I metal ions on enzyme-like oxidative coupling activity ». New Journal of Chemistry 44, no 35 (2020) : 14849–58. http://dx.doi.org/10.1039/d0nj02347g.

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In transition-metal-mediated catalysis, design of new, well defined coordination architectures and subjecting them to catalysis testing under the same reaction conditions is a necessity tool for improved understanding of desirable active site geometries and characteristics.
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Wieghold, S., L. Nienhaus, F. L. Knoller, F. F. Schweinberger, J. J. Shepherd, J. W. Lyding, U. Heiz, M. Gruebele et F. Esch. « Plasmonic support-mediated activation of 1 nm platinum clusters for catalysis ». Physical Chemistry Chemical Physics 19, no 45 (2017) : 30570–77. http://dx.doi.org/10.1039/c7cp04882c.

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Nanometer-sized metal clusters are prime candidates for photoactivated catalysis, based on their unique tunable properties. Under visible light illumination, these non-plasmonic particles can get catalytically activated by coupling to a plasmonic substrate.
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Wang, Hong-Yu, Long-Jin Zhong, Gui-Fen Lv, Yang Li et Jin-Heng Li. « Photocatalytic dual decarboxylative alkenylation mediated by triphenylphosphine and sodium iodide ». Organic & ; Biomolecular Chemistry 18, no 29 (2020) : 5589–93. http://dx.doi.org/10.1039/d0ob01242d.

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Calabrese, Carla, Francesco Giacalone et Carmela Aprile. « Hybrid Catalysts for CO2 Conversion into Cyclic Carbonates ». Catalysts 9, no 4 (2 avril 2019) : 325. http://dx.doi.org/10.3390/catal9040325.

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The conversion of carbon dioxide into valuable chemicals such as cyclic carbonates is an appealing topic for the scientific community due to the possibility of valorizing waste into an inexpensive, available, nontoxic, and renewable carbon feedstock. In this regard, last-generation heterogeneous catalysts are of great interest owing to their high catalytic activity, robustness, and easy recovery and recycling. In the present review, recent advances on CO2 cycloaddition to epoxide mediated by hybrid catalysts through organometallic or organo-catalytic species supported onto silica-, nanocarbon-, and metal–organic framework (MOF)-based heterogeneous materials, are highlighted and discussed.
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Ito, Jun-ichi, et Hisao Nishiyama. « Asymmetric Catalysis Mediated by Optically Active Bis(oxazolinyl)phenyl Metal Complexes ». Journal of Synthetic Organic Chemistry, Japan 71, no 8 (2013) : 791–803. http://dx.doi.org/10.5059/yukigoseikyokaishi.71.791.

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Horton, N. C., K. J. Newberry et J. J. Perona. « Metal ion-mediated substrate-assisted catalysis in type II restriction endonucleases ». Proceedings of the National Academy of Sciences 95, no 23 (10 novembre 1998) : 13489–94. http://dx.doi.org/10.1073/pnas.95.23.13489.

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Thomas, Sophie R., et Angela Casini. « Gold compounds for catalysis and metal-mediated transformations in biological systems ». Current Opinion in Chemical Biology 55 (avril 2020) : 103–10. http://dx.doi.org/10.1016/j.cbpa.2019.12.007.

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Levi, Noam, Dafna Amir, Eytan Gershonov et Yossi Zafrani. « Recent Progress on the Synthesis of CF2H-Containing Derivatives ». Synthesis 51, no 24 (30 septembre 2019) : 4549–67. http://dx.doi.org/10.1055/s-0039-1690027.

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Recent years have witnessed a growing interest in the development of novel synthetic methods and new reagents for the synthesis of difluoromethylated compounds. Dozens of studies have been published on this topic each year over the past few years. These studies are focused on direct and indirect difluoromethylation of various organic functionalities via nucleophilic-, electrophilic-, radical-, carbene- or metal-mediated mechanisms. The present short review covers the very recent studies, published between mid-2017 and early 2019, on the synthesis of compounds containing a CF2H group. A brief summary of the physicochemical properties and medicinal applications of difluoromethylated compounds is also included.1 Introduction2 Nucleophilic Difluoromethylation2.1 Metal-Mediated Nucleophilic Difluoromethylation2.2 Non-Metal Difluoromethyl Nucleophiles3 Radical Difluoromethylation3.1 Metal-Induced Radical Difluoromethylation3.2 Non-Metal-Induced Radical Difluoromethylation3.3 Electrochemically Induced Radical Difluoromethylation4 Carbene-Based Difluoromethylation4.1 Metal-Induced Carbene Difluoromethylation4.2 Non-Metal-Induced Difluoromethyl Carbenes5 Cross-Coupling Difluoromethylation5.1 Palladium-Catalyzed Difluoromethylation5.2 Nickel-Catalyzed Difluoromethylation5.3 Copper-Mediated Difluoromethylation5.4 Iron-Catalyzed Difluoromethylation5.5 Gold-Mediated Difluoromethylation6 Electrophilic Difluoromethylation7 Other Examples7.1 A Difluoromethyl-Borane Complex7.2 A Tellurium Difluoromethyl Derivative8 Summary
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Bao, Yunhui, Jian He, Ke Song, Jie Guo, Xianwu Zhou et Shima Liu. « Plant-Extract-Mediated Synthesis of Metal Nanoparticles ». Journal of Chemistry 2021 (18 août 2021) : 1–14. http://dx.doi.org/10.1155/2021/6562687.

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Metal nanoparticles (MNPs) have been widely used in several fields including catalysis, bioengineering, photoelectricity, antibacterial, anticancer, and medical imaging due to their unique physical and chemical properties. In the traditional synthesis method of MNPs, toxic chemicals are generally used as reducing agents and stabilizing agents, which is fussy to operate and extremely environment unfriendly. Based on this, the development of an environment-friendly synthesis method of MNPs has recently attracted great attention. The use of plant extracts as reductants and stabilizers to synthesize MNPs has the advantages of low cost, environmental friendliness, sustainability, and ease of operation. Besides, the as-synthesized MNPs are nontoxic, more stable, and more uniform in size than the counterparts prepared by the traditional method. Thus, green preparation methods have become a research hotspot in the field of MNPs synthesis. In this review, recent advances in green synthesis of MNPs using plant extracts as reductants and stabilizers have been systematically summarized. In addition, the insights into the potential applications and future development for MNPs prepared by using plant extracts have been provided.
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Dong, Shuqi, Jinjin Chen, Kening Qiao, Jian Fang, Yan Yang, Laurent Maron et Bo Liu. « Insights into Rare-Earth Metal Complex-Mediated Hydroamination ». ACS Catalysis 11, no 7 (12 mars 2021) : 3790–800. http://dx.doi.org/10.1021/acscatal.1c00566.

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Zhang, Zhuhua, Yang Yang, Guoying Gao et Boris I. Yakobson. « Two-Dimensional Boron Monolayers Mediated by Metal Substrates ». Angewandte Chemie International Edition 54, no 44 (2 septembre 2015) : 13022–26. http://dx.doi.org/10.1002/anie.201505425.

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