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Artigos de revistas sobre o assunto "Catalyse bioinspirée"
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Carrión, Erik N., Andrei Loas, Hemantbhai H. Patel, Marius Pelmuş, Karpagavalli Ramji e Sergiu M. Gorun. "Fluoroalkyl phthalocyanines: Bioinspired catalytic materials". Journal of Porphyrins and Phthalocyanines 22, n.º 05 (17 de abril de 2018): 371–97. http://dx.doi.org/10.1142/s1088424618500189.
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The design of self oxidation-resistant catalytic materials based on organic molecules, although advantageous due to the ability to control their structures, is limited by the presence of labile C–H bonds. This mini review summarizes recent work aimed at first-row transition metal complexes of a new class of coordinating ligands, fluoroalkyl-substituted fluorophthalocyanines, R[Formula: see text]Pcs, ligands in which all, or the majority of their C–H bonds are replaced by a combination of fluoro- and perfluoroalkyl groups yielding porphyrin-bioinspired catalyst models. In the case of homogeneous systems, cobalt(II) complexes catalyze the aerobic oxidation of thiols to disulfides, a reaction of both biological significance and industrial importance. Zinc(II) complexes photo-generate excited state singlet oxygen, [Formula: see text]O[Formula: see text], resulting in both the incorporation of O[Formula: see text] in C–H bonds or, depending on the reaction parameters, oxidation of dyes, model pollutants. Catalyst heterogenization using oxidic and other supports yields stable, active hybrid materials. Functionalized R[Formula: see text]Pcs with acidic (–COOH) or basic (–NH[Formula: see text]R[Formula: see text], [Formula: see text] 2) groups exhibit scaffolds that afford both conjugation with biological vectors for theranostic applications as well as solid-supported materials with superior stability. Electrodes modified with hybrid R[Formula: see text]Pc-containing supports have also been used in photo-oxidations, replacing enzymes and H[Formula: see text]O[Formula: see text] associated reagents with a combination of light and air. An analytical device employed for the nano-level detection of environmentally deleterious antibiotics has been constructed.
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Chen, Jing, Yingchun Guo, Tengteng Kang, Xingchi Liu, Xiaomei Wang e Xu Zhang. "In Situ Growth of ZIF-8 Nanocrystals on the Pore Walls of 3D Ordered Macroporous TiO2 for a One-Pot Cascade Reaction". Catalysts 11, n.º 5 (21 de abril de 2021): 533. http://dx.doi.org/10.3390/catal11050533.
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It is wise to mimic a bioinspired system to design a nanoreactor as a catalyst containing multiple components for a cascade reaction. Here, we report the uniform growth of well-dispersed nano-scale ZIF-8 crystals on the pore walls of 3DOM TiO2 via the TEA-assisted crystallization process. The UV-vis spectra indicate that the ZIF-8 photosensitizer can extend the visible-light absorption of 3DOM TiO2. The obtained nanoreactor can efficiently catalyze the one-pot aromatic alcohol oxidization and Knoevenagel condensation cascade reaction for larger molecules. This work offers an important strategy for preparing semiconductor–MOF multifunctional composites with a spatially separated compartmentation for the cascade reaction.
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Monkcom, Emily C., Pradip Ghosh, Emma Folkertsma, Hidde A. Negenman, Martin Lutz e Robertus J. M. Klein Gebbink. "Bioinspired Non-Heme Iron Complexes: The Evolution of Facial N, N, O Ligand Design". CHIMIA International Journal for Chemistry 74, n.º 6 (24 de junho de 2020): 450–66. http://dx.doi.org/10.2533/chimia.2020.450.
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Iron-containing metalloenzymes that contain the 2-His-1-Carboxylate facial triad at their active site are well known for their ability to activate molecular oxygen and catalyse a broad range of oxidative transformations. Many of these reactions are synthetically challenging, and developing small molecular iron-based catalysts that can achieve similar reactivity and selectivity remains a long-standing goal in homogeneous catalysis. This review focuses on the development of bioinspired facial N,N,O ligands that model the 2-His-1-Carboxylate facial triad to a greater degree of structural accuracy than many of the polydentate N-donor ligands commonly used in this field. By developing robust, well-defined N,N,O facial ligands, an increased understanding could be gained of the factors governing enzymatic reactivity and selectivity.
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Nothling, Mitchell D., Zeyun Xiao, Nicholas S. Hill, Mitchell T. Blyth, Ayana Bhaskaran, Marc-Antoine Sani, Andrea Espinosa-Gomez et al. "A multifunctional surfactant catalyst inspired by hydrolases". Science Advances 6, n.º 14 (abril de 2020): eaaz0404. http://dx.doi.org/10.1126/sciadv.aaz0404.
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The remarkable power of enzymes to undertake catalysis frequently stems from their grouping of multiple, complementary chemical units within close proximity around the enzyme active site. Motivated by this, we report here a bioinspired surfactant catalyst that incorporates a variety of chemical functionalities common to hydrolytic enzymes. The textbook hydrolase active site, the catalytic triad, is modeled by positioning the three groups of the triad (-OH, -imidazole, and -CO2H) on a single, trifunctional surfactant molecule. To support this, we recreate the hydrogen bond donating arrangement of the oxyanion hole by imparting surfactant functionality to a guanidinium headgroup. Self-assembly of these amphiphiles in solution drives the collection of functional headgroups into close proximity around a hydrophobic nano-environment, affording hydrolysis of a model ester at rates that challenge α-chymotrypsin. Structural assessment via NMR and XRD, paired with MD simulation and QM calculation, reveals marked similarities of the co-micelle catalyst to native enzymes.
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Guo, Hao, Yu-Fei Ao, De-Xian Wang e Qi-Qiang Wang. "Bioinspired tetraamino-bisthiourea chiral macrocycles in catalyzing decarboxylative Mannich reactions". Beilstein Journal of Organic Chemistry 18 (2 de maio de 2022): 486–96. http://dx.doi.org/10.3762/bjoc.18.51.
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A series of tetraamino-bisthiourea chiral macrocycles containing two diarylthiourea and two chiral diamine units were synthesized by a fragment-coupling approach in high yields. Different chiral diamine units, including cyclohexanediamines and diphenylethanediamines were readily incorporated by both homo and hetero [1 + 1] macrocyclic condensation of bisamine and bisisothiocyanate fragments. With the easy synthesis, gram-scale of macrocycle products can be readily obtained. These chiral macrocycles were applied in catalyzing bioinspired decarboxylative Mannich reactions. Only 5 mol % of the optimal macrocycle catalyst efficiently catalyzed the decarboxylative addition of a broad scope of malonic acid half thioesters to isatin-derived ketimines with excellent yields and good enantioselectivity. The rigid macrocyclic framework and the cooperation between the thiourea and tertiary amine sites were found to be crucial for achieving efficient activation and stereocontrol. As shown in control experiments, catalysis with the acyclic analogues having the same structural motifs were non-selective.
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Gao, Bin, Tao Wang, Yang Li, Xiaoli Fan, Hao Gong, Cheng Jiang, Peng Li, Xianli Huang e Jianping He. "Promoting hole transfer for photoelectrochemical water oxidation through a manganese cluster catalyst bioinspired by natural photosystem II". Chemical Communications 56, n.º 30 (2020): 4244–47. http://dx.doi.org/10.1039/d0cc00955e.
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Deuss, Peter J., René den Heeten, Wouter Laan e Paul C. J. Kamer. "Bioinspired Catalyst Design and Artificial Metalloenzymes". Chemistry - A European Journal 17, n.º 17 (23 de março de 2011): 4680–98. http://dx.doi.org/10.1002/chem.201003646.
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Hunter, R. D., J. Davies, S. J. A. Hérou, A. Kulak e Z. Schnepp. "Milling as a route to porous graphitic carbons from biomass". Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 379, n.º 2209 (13 de setembro de 2021): 20200336. http://dx.doi.org/10.1098/rsta.2020.0336.
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This paper reports a simple way to produce porous graphitic carbons from a wide range of lignocellulosic biomass sources, including nut shells, softwood sawdust, seed husks and bamboo. Biomass precursors are milled and sieved to produce fine powders and are then converted to porous graphitic carbons by iron-catalysed graphitization. Graphitizing the raw (unmilled) biomass creates carbons that are diverse in their porosity and adsorption properties. This is due to the inability of the iron catalyst precursor to penetrate the structure of dense biomass material. Milling enables much more efficient impregnation of the biomass and produces carbons with homogeneous properties. Lignocellulosic biomass (particularly waste biomass) is an attractive precursor to technologically important porous graphitic carbons as it is abundant and renewable. This simple method for preparing the biomass enables a wide range of biomass sources to be used to produce carbons with homogeneous properties. This article is part of the theme issue ‘Bio-derived and bioinspired sustainable advanced materials for emerging technologies (part 2)’.
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Sankar Agarwalla, Uday. "Bioinspired Non-heme Diiron Catalysts for Olefin Epoxidation with Hydrogen Peroxide in the Presence of Acetic Acid". International Journal of Science and Research (IJSR) 11, n.º 4 (5 de abril de 2022): 1089–93. http://dx.doi.org/10.21275/sr22403000114.
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Phillips, Katherine R., Grant T. England, Steffi Sunny, Elijah Shirman, Tanya Shirman, Nicolas Vogel e Joanna Aizenberg. "A colloidoscope of colloid-based porous materials and their uses". Chemical Society Reviews 45, n.º 2 (2016): 281–322. http://dx.doi.org/10.1039/c5cs00533g.
Texto completo da fonteTeses / dissertações sobre o assunto "Catalyse bioinspirée"
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Dias, Hugo. "Catalyseurs bioinspirés pour la valorisation du co2 en carbonates cycliques". Electronic Thesis or Diss., Lyon 1, 2024. http://www.theses.fr/2024LYO10192.
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La valorisation du CO2 est une stratégie pouvant permettre la résolution de problématiques contemporaines. En employant comme réactif cette molécule abondante considérée comme un déchet anthropique, la mise en place de synthèses durables de produits à haute valeur ajoutée devient alors un enjeu primordial pour l’industrie chimique. La synthèse des carbonates cycliques est un exemple caractéristique d’une réaction verte convertissant du CO2 en produits d’intérêt pour l’industrie des polymères ou des batteries au lithium. Néanmoins, la cycloaddition du CO2 aux époxydes requiert l’emploi de catalyseurs sélectifs pour éviter la formation de polymères indésirables. Au sein du vivant, l’anhydrase carbonique a été largement étudiée et reconnue pour sa capacité réversible à convertir rapidement du CO2 en HCO3-. Cependant, l’application de cette métalloenzyme est proscrite à plus grande échelle en raison de son instabilité en dehors des conditions physiologiques et de son coût exorbitant. En s’inspirant de cette macromolécule dont le site actif est un complexe de zinc entouré de ligands L-histidine, l’objectif de ce travail de thèse a été de développer un système catalytique sélectif pour la synthèse des carbonates cycliques en conditions douces. Des évaluations catalytiques de sels de zinc et dérivés de L-histidine ont été effectuées et ont mené aux synthèses et caractérisations exhaustives d’une série de complexes de zinc. Leur stabilité et activité couplées à une sélectivité en carbonates cycliques a motivé une étude complémentaire afin de greffer ces complexes sur supports. Dans ce but, des silices mésoporeuses fonctionnalisées ont été préparées et leur activité catalytique testée permettant le recyclage de ces catalyseurs bioinspirés sélectifsThe CO2 valorisation is a strategy that could solve current issues. By using as a reagent this abundant molecule which is considered as an anthropogenic waste product, the development of sustainable syntheses of high added value products is becoming a key challenge for the chemical industry. The synthesis of cyclic carbonates is a typical example of a green reaction that converts CO2 into useful products for polymer and lithium battery industries. However, the CO2 cycloaddition to epoxides requires the use of selective catalysts to avoid the formation of undesirable polymers. Within living organisms, carbonic anhydrase has been widely studied and recognised for its reversible ability to rapidly convert CO2 into HCO3-. Nevertheless, the application of this metalloenzyme is prohibited for an industrial use due to its instability outside physiological conditions and its expensive cost. Inspired from this macromolecule whose active site is a zinc complex surrounded by L-histidine ligands, the aim of this thesis was to develop a selective catalytic system for the synthesis of cyclic carbonates under mild conditions. Catalytic evaluations of zinc salts and L-histidine derivatives were carried out and led to syntheses and exhaustive characterisations of a series of zinc complexes. Their stability and activity coupled with their selectivity towards cyclic carbonates prompted further researches into the grafting of those complexes onto supports. Functionalised mesoporous silicas were prepared and their catalytic activity tested, enabling those selective bioinspired catalysts to be recycled
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Diao, Donglin. "Bioinspired complexes engaged within hemicryptophane cage-ligands for O2 activation and C-H bond functionalization in confined space". Electronic Thesis or Diss., Ecole centrale de Marseille, 2022. http://www.theses.fr/2022ECDM0007.
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L’objectif de ces travaux de thèse est le développement de nouveaux ligand-cages hémicryptophanes pour l’obtention de catalyseurs métalliques confinés. Ces catalyseurs seront utilisés pour l’activation bioinspirée d’O2 et la fonctionnalisation C-H en milieu confiné. Le design des cages cibles vise à introduire des ligands bioinspirés pour la coordination de métaux biologiques (Cu, Fe, Zn). La structure hémicryptophane offre une cavité hydrophobe au voisinage du site actif métallique. Cette structure vise à stabiliser les espèces actives et obtenir des réactivités différentes de celles obtenues avec les modèles ouverts correspondants. Dans ce contexte, l’objectif principale de ce travail a été d’obtenir des complexes de cuivre confinés capable d’activer l’oxygène moléculaire pour accomplir des réactions difficiles de fonctionnalisation C-H. La première partie de cette thèse consiste en étude bibliographique de (i) les précédentes applications des hémicryptophanes et (ii) les progrès récents sur les complexes bioinspirés encagés. Ensuite, nos complexes de cuivres à ligands tris(pyridyl)amine (TPA) ouverts et encagés, ont été étudiés pour l’activation d’O2 et pour des réactions non-usuelle de fonctionalisation de liaisons C-H. Nous avons ensuite préparé et étudié une nouvelle cage TPA-hemicryptophane équipée d’une cavité donneuse de liaisons hydrogène C(triazole)-H. Cette cavité fonctionnalisée vise à reproduire les cavités des métalloprotéines. Enfin, des hémicryptophanes basés sur le ligand triazacyclononane (TACN), ont été préparé pour la première fois. L’objectif de ces nouveaux ligand-cages est de contribuer au développement de complexes bioinspirés à Cu et Fe pouvant, par exemple, activer O2This thesis aims at developing new hemicryptophane cage-ligands to obtain confined metal-based catalysts for bioinspired O2 activation and C-H bond functionalization in confined space. The design of the targeted cages aims at introducing ligands inspired from metalloproteins active sites, for coordination of biorelevant metals (Cu, Fe, Zn). Importantly, the hemicryptophane structure provide a hydrophobic cavity around the active metal core. This structure aims at stabilizing highly reactive intermediates and reaching different reactivity compare to open model complexes, devoid of cavity. In this context, a major objective of this work was to reach Cu-based bioinspired catalysts able to activate molecular oxygen for challenging C-H bond functionalization. The first part of the thesis consists in a comprehensive literature survey on (i) background of previous applications of hemicryptophane cages and (ii) recent advances in caged bioinspired complexes. The application of our open and caged Cu-complex, based on the tris(pyridyl)amine (TPA) ligand is next described. These catalysts have been used for O2 activation and unusual intramolecular C-H bond functionalization. We then prepare and studied a new TPA-hemicryptophane cage equipped with a C(triazole)-H hydrogen bonding cavity. This functionalized cavity aims at reproducing the binding cavities found in metalloproteins. Finally, hemicryptophane cages based on the triazacyclononane (TACN) ligand have been prepared for the first time. The goal of these cage-ligands is to develop new bioinspired Cu and Fe complexes that could be, for instance, used as O2 activating catalysts
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Bécart, Diane. "Bioinspired catalysis using oligourea helical foldamers". Thesis, Bordeaux, 2017. http://www.theses.fr/2017BORD0717/document.
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Catalyse et repliement sont deux notions intimement liées dans la Nature à travers les protéines et les enzymes, puis par extension, avec les catalyseurs synthétiques conçus par les chimistes. Des briques élémentaires artificielles ont été développées depuis deux décennies afin de synthétiser de nouvelles architectures moléculaires ayant une forte propension à se replier, appelées foldamères. Dans de nombreux systèmes biomimétiques inspirés par les biopolymères, la stabilisation d’une forme repliée résulte de la formation d’un fort réseau de liaisons H. Ces squelettes repliés apportent plusieurs avantages pour une application en catalyse : ils peuvent offrir un effet coopératif lors de la coordination d’un ligand, une meilleure stabilisation des intermédiaires chargés ainsi qu’une minimisation du coût entropique de la formation de l’état de transition. Ils constituent une nouvelle classe d’organocatalyseurs méritant de plus amples investigations. L’organocatalyse présente un fort intérêt dans la recherche actuelle, dû la simplicité de mise en œuvre des systèmes et l’absence de métaux conduisant à une moindre toxicité. Cependant, des charges importantes (5-20 mol%) en catalyseur sont souvent nécessaires pour réaliser des transformations chimiques avec de bons rendements et de bonnes stéréosélectivités. L’effet synergique apporté par la structure bien définie des foldamères via leur fort réseau de liaisons hydrogène peut jouer en faveur d’une diminution de la charge catalytique du système.Les foldamères à base de motifs oligo(thio)urées sont des analogues des peptides, avec une structure secondaire hélicoïdale, 2.5 résidus par tour et un réseau de liaisons hydrogène fermant des pseudo-cycles à 12 et 14 atomes, et ils présentent un macrodipôle pouvant être renforcé par l’activation avec un groupe électroattracteur au niveau du pôle positif. La liaison d’anions avec des oligourées a été démontrée comme étant site-spécifique et n’ayant aucune influence sur la structure hélicoïdale, illustrant leur fort potentiel de liaison d’espèces chargés négativement. Les urées et les thiourées ont été largement utilisées comme donneurs de liaisons hydrogène pour l’organocatalyse avec des résultats très satisfaisants. Ces concepts posent les bases pour développer un organocatalyseur innovant avec des foldamères oligo(thio)urées, interagissant par activation des substrats par formation de liaisons H. Une étude autour de la relation structure-activité, accompagnée de l’élaboration d’une réaction modèle avec un large panel de substrats, ainsi que des études mécanistiques via des mesures RMN, vont permettre d’établir les principes gouvernant la catalyse avec des foldamères oligo(thio)uréesCatalysis and folding are two closely interwoven notions in Nature particularly among enzymes, and by extension can be applied to synthetic catalysts designed by chemists. Artificial monomers have been created for two decades to synthesize new oligomeric molecular architectures with a high propensity to fold, which are called foldamers. In many systems, folded structure is stabilized by a strong hydrogen-bonding network, in a similar way to biopolymer structures. These folded backbones may provide significant advantages as catalyst as they could offer cooperativity in ligand binding, a greater stabilization of charged intermediates and then a minimization of entropic cost of the transition state binding. They constitute a class of potential organocatalysts which deserves more investigation. Organocatalysis is an area of strong interest nowadays because of the lower toxicity of the catalysts and meta free procedures, their modularity and easiness to handle them. But generally high loading (5-20 mol%) are needed to perform chemical transformations with good yields and good stereoselectivities. The synergistic effect brought by the well-defined structures of foldamers through the strong hydrogen-bonding network can be in favour of a decrease of the catalyst loading.Oligo(thio)urea foldamers are peptides analogues, with a helical secondary structure, 2.5 residues per turn and 12- and 14-membered H-bond ring and present a macrodipole which can be reinforced through activation with electro-withdrawing group at the positive pole. Binding of anions to oligourea has been studied and was shown to be site specific and not to have any impact on the helical structure thus illustrating the high potential of coordination of negatively charged species to oligourea foldamers. Urea and thiourea small molecules have been widely used as H-bond donors for organocatalysis with very satisfying results. These concepts are the basis of the development of an innovative organocatalyst with oligo(thio)urea foldamers, acting through H-bond activation. A structure-activity relationship study combining an extended substrate scope and NMR mechanistic studies was performed allowing delineation of the principles governing oligourea foldamer-based catalysis
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Hacihasanoglu, Antoine. "Biomimetic asymmetric catalysis with bioinspired helical foldamers". Thesis, Bordeaux, 2022. http://www.theses.fr/2022BORD0166.
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L’organocatalyse est une méthodologie qui connait un développement rapide, permettant de réaliser des transformations chimiques complexes dans le contexte général de la chimie durable (procédés sans métaux, recyclage des catalyseurs…). Les applications potentielles incluent l'élaboration rapide d'éléments de base avancés et utiles pour le développement pharmaceutique. Malgré de grandes réalisations, les organocatalyseurs souffrent généralement de certaines limitations comme une faible accélération de la réaction, d'un taux de rotation catalytique faible et de la nécessité de quantités importantes de catalyseur pour obtenir une bonne conversion et sélectivité. Afin de répondre à ces limitations, des catalyseurs incorporant de plus en plus de fonctions d'interaction afin d'exercer un contrôle plus important sur l'état de transition de réactions ont été des axes de recherche populaires. Un second axe consistant à utiliser des catalyseurs pré-structurés, analogues simplifiés des enzymes à également commencé à être étudié. Les foldamères d'oligourées développées par notre laboratoire ont précédemment démontré la capacité de catalyse dans le cadre de la réaction d'additions de composés 1,3-dicarbonylés aux nitroalcènes avec de très faibles charges catalytiques et d'excellentes stéréosélectivités. Les travaux présentés font suite à ces résultats et ont pour but d'étudier le mécanisme d'interaction du catalyseur, puis d'explorer de nouvelles réactions catalysées par nos foldamèresOrganocatalysis is a rapidly expanding methodology enabling challenging chemical transformations to be performed in the broad context of sustainable chemistry (metal-free procedures, catalyst recycling…). Potential applications include the rapid elaboration of advanced and useful building blocks for pharmaceutical development. Despite major achievements, organocatalysts generally suffer from low rate acceleration and turnover and the need for relatively high amounts to achieve good conversion and selectivity. In order to address these limitations, catalyst structures incorporating increasing numbers of interacting functions to better control the transitions state of reactions have been a popular axis of research. A second, more recent approach has been the use of pre-organised catalysts, which can be viewed as simplified enzyme analogues. In this context, the oligourea foldamers developed by our group have previously been shown to catalyse the addition of 1,3-dicarbonyl compounds to nitroalkenes with low catalyst loading and excellent stereoselectivities. The works presented hereby come in continuation of these previous results with the main objectives being the study of the mechanism of interaction between the catalyst and substrates, and the exploration of new potential reactions catalysed by our foldamers
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Clarasó, Petit Carlota. "Rational design of bioinspired iron and manganese catalysts for the effective and selective epoxidation of alkenes and oxidation of alkanes". Doctoral thesis, Universitat de Girona, 2019. http://hdl.handle.net/10803/666958.
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Metalloenzymes are a fundamental source of inspiration for synthetic chemists. Oxidation metalloenzymes catalyze oxidation reactions with high efficiency under very mild experimental conditions exhibiting exquisite regio- and stereoselectivity. The present dissertation aims at designing efficient and selective bioinspired oxidation catalysts. Looking at the literature there’s a very limited number of aliphatic diamines incorporated as ligand backbones in tetradentate aminopyridine based complexes, which have been revealed as one of the most successful catalysts for these transformations with peroxide type of oxidants. Thus, this thesis is focused on the synthesis of chiral iron and manganese complexes based on novel diamine backbones and employ them as catalysts in the stereoselective epoxidation of olefins and oxidation of C-H bonds by using hydrogen peroxide as oxidantEls metal·loenzims són una font fonamental d'inspiració per als químics sintètics. Els metal·loenzims oxidants catalitzen reaccions d'oxidació amb gran eficiència sota condicions experimentals molt suaus que presenten regio- i estereoselectivitats exquisides. L'objectiu d’aquesta tesi es basa en el disseny de catalitzadors d'oxidació bioinspirats eficients i selectius. Analitzant la literatura, es denota que hi ha una limitació important en el nombre i la naturalesa de la diamina incorporada als lligands en complexos basats en lligands tetradentats amb aminopiridines, que s'han demostrat com uns dels catalitzadors més exitosos per a aquestes transformacions amb oxidants de tipus peròxid. Així doncs, aquesta tesi se centra en la síntesi de complexos quirals de ferro i manganès basats en lligands tetradentats que incorporen noves diamines i el seu ús com a catalitzadors en l'epoxidació estereoselectiva d’olefines i l'oxidació dels enllaços C-H utilitzant el peròxid d'hidrogen com a oxidant
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Dzierzak, Joanna. "Bioinspired, heterogeneous amino acid complexes for benign oxidation catalysis". Thesis, University of Southampton, 2011. https://eprints.soton.ac.uk/334198/.
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Metalloenzymes catalyse the most fundamental reactions in organic chemistry from oxidation of hydrocarbons to complex C-C bond forming reactions with exceptional selectivity. Mimicking the active site of a metalloenzyme by immobilising well-defined amino acids containing catalytically active transition metal centres based on transitionmetals on a robust inorganic framework, affords powerful catalysts that can be utilised in oxidation reactions. Porous aluminosilicates, mesoporous silicas and polymers offer suitable supports for single-site bio-derived catalysts. Dispersion of catalytically active centers within porous solids with high surface area improves site-isolation which is essential in catalytic processes. These materials can be created from a range of methodologies and the different strategies used for immobilisation can greatly affect the nature of the active catalyst. The routes by which these catalysts are immobilised have given the potential to derivatize inorganic porous hosts and organic polymer structures with amino acids for complexation to metal centres. These bio-derivatized frameworks offer advantages over the homogeneous counterparts in terms of easy separation, recover and recyclability and can carry out selective oxidation reactions with great effectiveness. Herein, heterogenous bioinspired complexes of two amino acids; proline and valine with a series of transition metals (Fe, Cu) were synthesised and immobilised within zeolite cages, mesoporous silica MCM-41 and polystyrene. The preparation methods allowed the synthesis of materials with varying loadings of immobilized active sites. The structural information obtained by spectral and elemental analysis suggested tetrahedral geometry for iron complexes and distorted square planar geometry for copper complexes. Both amino acids coordinated to metal ions through the nitrogen atom of amino group and oxygen atom of carboxylate group via dissociation of the acidic proton as bidentate N,O-donors. The resulting biomimetic complexes were employed as catalysts for oxidation of cyclohexane, cyclohexene, benzyl alcohol and dimethyl sulfide, using molecular dioxygen (O2), tert-butyl hydroperoxide (TBHP) and acetylperoxyborate (APB) as oxidants. The observed trends in catalytic activity showed that the metal loading and separation of the active sites played key role in the selective oxidation reactions. By decreasing the loading of metal active centres, their spatial separation increased which strongly enhanced the activity of catalysts. The decrease in metal active site content resulted in significant increase in TON and TOF. The product selectivity was dependent on the nature of oxidant, hydrophobicity/hydrophilicity of the support, loading of metal active centres and the metal/substrate ratio.
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Porcher, Jean-Philippe. "Synthèse de complexes bioinspirés de Mo et W catalyseurs pour la réduction des protons". Thesis, Paris 6, 2015. http://www.theses.fr/2015PA066301/document.
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Les enzymes à molybdène ou à tungstène sont présentes dans toutes les formes de vie. La plupart d’entre elles sont des oxotransférases ou des hydroxylases. Elles contiennent un ou deux cofacteurs à molybdoptérine Moco coordiné au centre métallique par une fonction dithiolène. Ce cofacteur est très instable et la synthèse de complexes biomimétiques est difficile. Dans cette thèse, une nouvelle stratégie de synthèse d’un ligand dithiolène (qpdt) analogue du cofacteur à molybdoptérine a été développée. Le complexe de molybdène (Bu4N)2[MoO(qpdt)2] correspondant a été synthétisé et caractérisé. Ce complexe unique a montré un fort potentiel pour la réduction des protons. La photoréduction des protons en milieu acide (pH = 4), en présence du complexe de molybdène, du photosensibilisateur Ru(bpy)32+ et d’un excès d’acide ascorbique, donne d’excellentes activités allant jusqu’à 500 TONs en 15 heures. Ce complexe a aussi montré une très grande stabilité en milieu organique-acqueux. De même, l’électroréduction des protons par ce complexe dans l’acétonitrile a mis en évidence une constante de vitesse remarquable de 1030 s-1 à un potentiel de 1.3 V (vs Ag/AgCl). Afin de valoriser ce ligand original, les complexes bisdithiolène de nickel (Et4N)[Ni(qpdt)2] et de cobalt (Et4N)2[Co(qpdt)2]2 ont été synthétisés et caractérisés. Des études préliminaires de ces complexes ont montré un potentiel pour la photoréduction et l’électroréduction des protons. L’ensemble de ces résultats ouvre de nouvelles perspectives pour le développement de catalyseurs pour la réduction des protons. De plus, la synthèse de ce premier complexe biomimétique devrait permettre de mieux comprendre la chimie de ces enzymes encore peu connuesEnzymes containing molybdenum or tungsten within their active sites appear to be present in all form of life. Most of them are oxotransferase or hydroxylase. They contain one or two pyranopterin-dithiolene cofactor, also called Moco, in which the metal is coordinated by the dithiolene moiety. The molybdenum cofactor is highly unstable and mimicking the active site of these enzymes is challenging. A new strategy for the synthesis of a pyranopyrazine dithiolene ligand (qpdt) has been developed in our laboratory. The corresponding molybdenum complex (Bu4N)2[MoO(qpdt)2] was synthesized and characterized extensively. This unique Mo-enzyme biomimetic complex demonstrated its potential for H2 production. This complex was shown to be active for the photoreduction of protons in acidic conditions (pH = 4), in the presence of the catalyst, the photosensitizer Ru(bpy)32+, ascorbic acid in exces and gave excellent activities of 500 TON with a high stability in aqueous organic media. Moreover, the electroreduction of protons by this complex in acetonitrile showed a remarkable rate constant value of 1030 s-1 at 1.3 V. (vs Ag/AgCl). To valorize this very original ligand qpdt, (Et4N)[Ni(qpdt)2] and (Et4N)2[Co(qpdt)2]2 bisdithiolene complexes were synthesized and characterized. Preliminary studies of theses complexes have shown a potential for the photoreduction and the electroreduction of protons. These results open new directions for the search of proton reduction catalysts. This first biomimetic complex should also be exploited to understand the chemistry of this class of oxidoreductase that is still not well understood
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ZUCCA, PAOLO. "Supported Metalloporphines as novel and bioinspired Lignolytic Peroxidase-like Catalysts". Doctoral thesis, Università degli Studi di Cagliari, 2011. http://hdl.handle.net/11584/266340.
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Current, classical delignification processes are affected by some economical and environmental drawbacks. These approaches often seem to be inadequate, particularly in the perspective of a sustainable green process. Since immobilized metalloporphines can strictly emulate the active site of ligninolytic peroxidases, their use in delignification processes has been presented and future trends outlined.
In order to achieve a structural emulation, several coordinating groups have been used to coordinatively immobilize metalloporphines. Synthesized adducts
have been characterized by UV/vis and IR spectroscopies, and effective coordinative bond between metalloporphine and supports was shown.
The biomimetic catalysts have been also investigated about their peroxidase catalysis and ability to emulate lignolytic peroxidases action and substrate
specificity. The adducts showed a remarkable ability to catalyze veratryl alcohol oxidation at the expenses of H₂O₂. Kinetic and operational characterization of the catalysts is also reported. Both lignin peroxidase and manganese peroxidase–like catalysis have been obtained, under very mild experimental conditions, using many lignin model compounds. Redox mediation was possible,
allowing also treatment of water–insoluble substrates.
In the perspective of broadening industrial applications of the catalysts,the
bleaching of several pollutant and durable textile dyes has been attempted with similar promising results, resulting particularly suitable for industrial scaling up.
Accordingly, the inexpensiveness of the synthesis and the mild operational conditions allow these adducts to be proposed as feasible catalysts also for industrial large scale processes.-----------------------------------------
La rimozione della lignina dai materiali lignocellulosici costituisce una sfida industriale ancora aperta, poiché gli attuali approcci finora proposti non eccellono per economicità e sostenibilità ambientale del processo. Neppure quello biocatalitico (basato sia sugli enzimilignolitici, che sui microrganismi loro produttori, i funghi del marciume bianco) ha finora trovato un valido compromesso tra costo ed efficienza del processo.
Le perossidasi ligninolitiche tuttavia costituiscono ottimi modelli per la sintesi di catalizzatori biomimetici in grado di operare una delignificazione più
ecocompatibile: in particolare, sono state sviluppate numerose metalloporfine sintetiche che, libere nel mezzo di reazione, hanno mostrato promettenti proprietà catalitiche emulanti le perossidasi lignolitiche. Tuttavia, come tali non presentano alcuna applicabilità su larga scala, per ragioni di ordine economico.
Nel presente lavoro sono stati, dunque, sintetizzati alcuni catalizzatori biomimetici emulanti il sito attivo di questi enzimi, sfruttando supporti organici ed inorganici modificati chimicamente con funzioni in grado di legare tramite legame di coordinazione le metalloporfine sintetiche.
Gli addotti così sintetizzati sono stati dapprima caratterizzati tramite spettroscopia UV/Vis e FT–IR, ed è stato descritto come l’immobilizzazione avvenga
effettivamente attraverso un legame di coordinazione, mostrando pertanto un’effettiva emulazione strutturale delle perossidasi lignolitiche.
Successivamente, i catalizzatori sono stati caratterizzati dal punto di vista funzionale, evidenziando proprietà di emulazione sia della lignina perossidasi, che della manganese perossidasi in presenza dell’ossidante più eco–compatibile possibile: il perossido di idrogeno. L’amplissima specificità di substrato, la sintesi poco costosa ele condizionidi reazione estremamente blande(pH neutro, pressione e temperatura ambiente, ossidante ambientalmente compatibile e totale assenza di solventi organici) rendono questi catalizzatori quantomai adatti
allo scaling–up industriale nel trattamento di materiali lignocellulosici in genere.
Lo studio di mediatori di ossidoriduzione diffusibili suggerisce anche una loro possibile applicazione con substrati non solubili in acqua, poiché le forme ossidate di questi(ad esempio Mn(III) e VA•⁺) possono efficacemente fungere da tramite tra il catalizzatore eterogeneo e simili substrati.
Le potenzialità applicative degli addotti sono state ulteriormente ampliate attraverso uno screening di decolorazione di coloranti sintetici appartenenti a
classi chimiche differenti. Anche in questo caso l’elevata efficienza e le blande condizioni operative risultano essere promettenti in ottica applicativa.
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Cussó, Forest Olaf. "Highly enantioselective epoxidation with hydrogen peroxide and biologically inspired iron and manganese catalysts". Doctoral thesis, Universitat de Girona, 2016. http://hdl.handle.net/10803/393903.
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Asymmetric epoxidation is one of the most important reactions in synthetic organic chemistry, because chiral epoxides act as versatile electrophiles which can be converted in a number of interesting and useful chiral products. It’s known that current methodologies for obtaining excellent enantioselectivities need to be improved in terms of reaction times, use of not expensive or toxic metals, and avoidance of chlorinated solvents and oxidants that produce undesired wastes. Natural systems, such as iron enzymes are capable of perform this chemistry with high selectivity and efficiency under very mild conditions. Inspired by oxidations taking place at oxygenases, the combination of iron- and manganese-based catalysts and hydrogen peroxide is an attractive approach for developing oxidation methods because of availability, low cost and low toxicity considerations. One of the main objectives of this thesis is the development of iron and manganese complexes that mimics the structure and functions of these natural enzymes and the finding of new methodologies for enantioselective epoxidations using environmentally not aggressive conditions. One of the strategies developed in this thesis consists in investigating iron and manganese chiral coordination complexes with different electronic and steric properties on the ligand. Furthermore, it was envisioned that the study of these compounds could give useful information about the oxidation mechanism operating in oxygenase enzymes and may help to provide a basis for a rational design for future catalyst developments. The results obtained in this thesis show that the electronic properties of the ligand play an important role in order to get excellent enantioselectivities and different carboxylic acid additives can extent the substrate scope of the system. Finally, three new iron and manganese complexes are described as an efficient and stereoselective catalysts capable of performing highly enantioselective epoxidation of different kind of olefins, such as, cis-aromatic, trans-aromatic and also challenging substrates such as steroids, cyclic aliphatic enones and terminals olefins.L’epoxidació asimètrica és una de les reaccions més importants de la química orgànica. Perquè els epòxids quirals actuen com a electròfils versàtils, els quals poden ser convertits en productes quirals interessants i útils. És conegut que les metodologies actuals per obtenir altes enantioselectivitats necessiten ser millorades en termes de temps de reacció, l’ús de metalls tòxics i cars, i evitar dissolvents clorats i oxidants que produeixen subproductes no desitjats. Els sistemes natural, com els enzims de ferro, són capaços de dur a terme aquesta química amb altes selectivitats i eficiències sota condicions suaus. Inspirat en les oxidacions que tenen lloc en les oxigenases, la combinació de catalitzadors de ferro i manganès amb aigua oxigenada és un atractiu punt de partida per desenvolupar mètodes d’oxidació, degut a la seva disponibilitat, baix cost i baixa toxicitat. Un dels principals objectius d’aquesta tesis és el desenvolupament de catalitzadors de ferro i manganès que imiten l’estructura i les funcions dels enzims naturals i trobar una nova metodologia per fer epoxidacions enantioselectives utilitzant condicions no agressives. Una de les estratègies desenvolupades en aquesta tesis consisteix en investigar complexos de coordinació de ferro i manganès amb diferents propietats electròniques i estèriques en el lligand. A més, es preveu que els estudis d’aquests compostos podria donar informació útil sobre els mecanismes d’oxidació que operen en les oxigenases i també podria aportar conceptes bàsics per el disseny de futurs catalitzadors. Els resultats obtinguts en aquesta tesis mostren que les propietats electròniques dels lligands juguen un paper molt important a l’hora d’obtenir altes enantioselectivitats i l’ús de diferents àcids carboxílics pot expandir el nombre de substrats possibles a epoxidar d’aquest sistema. Finalment, tres nous complexos de ferro i manganès han esta descrits com a catalitzadors eficients i estereoselectiius capaços de dur a terme epoxidacions altament enantioselectives de diferents tipus d’olefines, com ara cis-olefines, trans-olefines i també substrats més difícils com ara, esteroides, enones cícliques alifàtiques i olefines terminals.
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Seeba, Marten. "Bioinspired dinuclear copper complexes for catalytic oxidation of phenolic substrates". Doctoral thesis, Niedersächsische Staats- und Universitätsbibliothek Göttingen, 2017. http://hdl.handle.net/11858/00-1735-0000-002E-E4DC-8.
Texto completo da fonteLivros sobre o assunto "Catalyse bioinspirée"
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Weigand, Wolfgang, e Philippe Schollhammer, eds. Bioinspired Catalysis. Weinheim, Germany: Wiley-VCH Verlag GmbH & Co. KGaA, 2014. http://dx.doi.org/10.1002/9783527664160.
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Weigand, Wolfgang, e Philippe Schollhammer. Bioinspired Catalysis: Metal-Sulfur Complexes. Wiley & Sons, Incorporated, John, 2014.
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Weigand, Wolfgang, e Philippe Schollhammer. Bioinspired Catalysis: Metal-Sulfur Complexes. Wiley & Sons, Incorporated, John, 2014.
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Weigand, Wolfgang, e Philippe Schollhammer. Bioinspired Catalysis: Metal-Sulfur Complexes. Wiley-VCH Verlag GmbH, 2014.
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Weigand, Wolfgang, e Philippe Schollhammer. Bioinspired Catalysis: Metal-Sulfur Complexes. Wiley & Sons, Incorporated, John, 2014.
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Weigand, Wolfgang, e Philippe Schollhammer. Bioinspired Catalysis: Metal-Sulfur Complexes. Wiley & Sons, Limited, John, 2014.
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JALILA. Copper Bioinorganic Chemistry Health Bhb : Copper Bioinorganic Chemistry: From Health to Bioinspired Catalysis. World Scientific Publishing Co Pte Ltd, 2023.
Encontre o texto completo da fonteCapítulos de livros sobre o assunto "Catalyse bioinspirée"
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Swiegers, Gerhard F., Jun Chen e Pawel Wagner. "Bioinspired Catalysis". In Bioinspiration and Biomimicry in Chemistry, 165–208. Hoboken, NJ, USA: John Wiley & Sons, Inc., 2012. http://dx.doi.org/10.1002/9781118310083.ch7.
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Wächtershäuser, Günter. "From Chemical Invariance to Genetic Variability". In Bioinspired Catalysis, 1–20. Weinheim, Germany: Wiley-VCH Verlag GmbH & Co. KGaA, 2014. http://dx.doi.org/10.1002/9783527664160.ch1.
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Dance, Ian. "A Unified Chemical Mechanism for Hydrogenation Reactions Catalyzed by Nitrogenase". In Bioinspired Catalysis, 249–88. Weinheim, Germany: Wiley-VCH Verlag GmbH & Co. KGaA, 2014. http://dx.doi.org/10.1002/9783527664160.ch10.
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Henderson, Richard A. "Binding Substrates to Synthetic Fe-S-Based Clusters and the Possible Relevance to Nitrogenases". In Bioinspired Catalysis, 289–324. Weinheim, Germany: Wiley-VCH Verlag GmbH & Co. KGaA, 2014. http://dx.doi.org/10.1002/9783527664160.ch11.
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Kumar, Davinder, e Craig A. Grapperhaus. "Sulfur-Oxygenation and FunctionalModels of Nitrile Hydratase". In Bioinspired Catalysis, 325–48. Weinheim, Germany: Wiley-VCH Verlag GmbH & Co. KGaA, 2014. http://dx.doi.org/10.1002/9783527664160.ch12.
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Schulzke, Carola, e Ashta Chandra Ghosh. "Molybdenum and Tungsten Oxidoreductase Models". In Bioinspired Catalysis, 349–82. Weinheim, Germany: Wiley-VCH Verlag GmbH & Co. KGaA, 2014. http://dx.doi.org/10.1002/9783527664160.ch13.
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Tran, Phong D., Marc Fontecave e Vincent Artero. "Electrode Materials and Artificial Photosynthetic Systems". In Bioinspired Catalysis, 383–410. Weinheim, Germany: Wiley-VCH Verlag GmbH & Co. KGaA, 2014. http://dx.doi.org/10.1002/9783527664160.ch14.
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Nicolet, Yvain, e Juan C. Fontecilla-Camps. "Fe-S Clusters: Biogenesis and Redox, Catalytic, and Regulatory Properties". In Bioinspired Catalysis, 21–48. Weinheim, Germany: Wiley-VCH Verlag GmbH & Co. KGaA, 2014. http://dx.doi.org/10.1002/9783527664160.ch2.
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Dawson, Joe, Carlo Perotto, Jonathan McMaster e Martin Schröder. "[NiFe] Hydrogenases". In Bioinspired Catalysis, 49–78. Weinheim, Germany: Wiley-VCH Verlag GmbH & Co. KGaA, 2014. http://dx.doi.org/10.1002/9783527664160.ch3.
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Apfel, Ulf-Peter, François Y. Pétillon, Philippe Schollhammer, Jean Talarmin e Wolfgang Weigand. "[FeFe] Hydrogenase Models: an Overview". In Bioinspired Catalysis, 79–104. Weinheim, Germany: Wiley-VCH Verlag GmbH & Co. KGaA, 2014. http://dx.doi.org/10.1002/9783527664160.ch4.
Texto completo da fonteTrabalhos de conferências sobre o assunto "Catalyse bioinspirée"
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Santi, Claudio, Marcello Tiecco, Lorenzo Testaferri, Elisabetta Rongoni, Lorenzo Di Schino, Loredana Incipini, Vincenza Dragone et al. "Bioinspired Use of Organoselenium Catalysts". In The 15th International Electronic Conference on Synthetic Organic Chemistry. Basel, Switzerland: MDPI, 2011. http://dx.doi.org/10.3390/ecsoc-15-00665.
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Sutter, Thomas M., Matthew B. Dickerson, Terry S. Creasy, Jeffery W. Baur e Ryan S. Justice. "Development of Localized, Light-Weight Pressurization Mechanisms: Approach, Feasibility, and Impact". In ASME 2012 Conference on Smart Materials, Adaptive Structures and Intelligent Systems. American Society of Mechanical Engineers, 2012. http://dx.doi.org/10.1115/smasis2012-8111.
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This work presents a novel gas-generation mechanism designed to enable bioinspired actuators. Specifically, the fundamental aspects involved in harnessing the gaseous products from biologically catalyzed reactions and recycling the gases into an actuation pressurization scheme are explored. The capability of having such a self-regulating, self-regenerating system of gas generation could provide the necessary pneumatically-driven force to enable devices that require localized pressurization, such as rubber muscle actuators. This work reports 1) the utilization of biological systems to produce gaseous products that will ultimately affect actuator density in situ, and 2) the construction of a freely moving power rig to monitor rubber muscle actuator performance under pressure generated from biologically powered reactions.