Teses / dissertações sobre o tema "Carbène NHC"
Crie uma referência precisa em APA, MLA, Chicago, Harvard, e outros estilos
Veja os 50 melhores trabalhos (teses / dissertações) para estudos sobre o assunto "Carbène NHC".
Ao lado de cada fonte na lista de referências, há um botão "Adicionar à bibliografia". Clique e geraremos automaticamente a citação bibliográfica do trabalho escolhido no estilo de citação de que você precisa: APA, MLA, Harvard, Chicago, Vancouver, etc.
Você também pode baixar o texto completo da publicação científica em formato .pdf e ler o resumo do trabalho online se estiver presente nos metadados.
Veja as teses / dissertações das mais diversas áreas científicas e compile uma bibliografia correta.
Haumesser, Julien. "Synthèse et caractérisation d'assemblages multi-porphyriniques à espaceurs NHC". Phd thesis, Université de Strasbourg, 2013. http://tel.archives-ouvertes.fr/tel-01017421.
Texto completo da fonteKong, Lingyu. "De ligands NHCs prochiraux à des complexes métal-NHC énantiopurs : nouvelles perspectives pour la catalyse asymétrique". Electronic Thesis or Diss., Aix-Marseille, 2019. http://www.theses.fr/2019AIXM0502.
Texto completo da fonteN-heterocyclic carbenes (NHC) are recognized to be excellent ligands towards transition metals ™. In this manuscript, the first chapter is dedicated to a non-exhaustive presentation of the various approaches of the literature which have been used to design chiral NHCs efficient in enantioselective catalysis. As a prelude of the second chapter, the new concept lies on the formation of an axis of chirality during the coordination between the NHC ligand and the transition metal. This chapter is dedicated to the synthesis of complexes with a C1 symmetry. Various imidazolium salts, have been synthesized and then used to generate palladium complexes. These complexes have been obtained in a enantiopurically form thanks to a chiral HLPC resolution at a preparative scale. These homochiral complexes were firstly subjected to studies aiming the investigation of their chiroptic properties and the determination of their rotation barriers values. The concept was then successfully extended to the synthesis of gold- and copper-based complexes. Homochiral copper-NHC complexes were found of particular importance since their applications in catalysis allowed to reach good enantioinductions and as NHC transfer reagents brought some experimental proofs on the transmetalation process. The third chapter disclosed the works that have been done on the preparation of heterochiral NHC-TM complexes possessing a C2 symmetry. Various symmetric imidazolium salts have been synthesized and then used to form the corresponding palladium-based complexes. Homochiral complexes were found displaying good activities for α-arylation of amides and excellent enantioselectivities (up to 98% ee)
Passays, Johan. "Nouveaux ligands mixtes de type phosphore / carbène N-hétérocyclique : synthèse et applications en catalyse asymétrique". Thesis, Rouen, INSA, 2011. http://www.theses.fr/2011ISAM0008.
Texto completo da fonteA straightforward method for the preparation of new bidentate ligands containing aphosphine or a phosphite and a carbene function was developed. Different phosphorus-imidazolium compounds were prepared according to this method. First, diphenylphosphine-NHC ligands featuring a stereogenic center a to the phosphine were synthesized from b-hydroxyesters. This strategy was then extended to the preparation of phosphite-imidazoliumand dialkylphosphine-imidazolium compounds. Complexation of these phosphorus-NHCligands with different metals like Ir or Rh was performed in order to study there catalytic properties in asymmetric hydrogenation
Tang, Shun. "Cycloisomérisations catalysées par les sels du gallium et les complexes NHC-Gallium(III)". Thesis, Paris 11, 2013. http://www.theses.fr/2013PA112271.
Texto completo da fonteRecently, in order to develop alternative activation methods for Pi-systems in homogeneous catalysis instead of employing expensive and toxic noble metal catalysts, first row transition metals and main group metal complexes have attracted great attention. This thesis is a contribution to it, and we focus on gallium chemistry. There are three main aspects dominating this thesis: gallium(III) halides, well-defined gallium(III) complexes bearing N-heterocyclic carbenes (NHCs), and -systems activation in catalysis.The thesis is divided into three chapters. Chapter I provides an overview of the field of organic synthesis involving gallium(III) compounds, focusing on their use as - or -Lewis acids.In Chapter II, we expose our attempts to exploit the catalytic potential of gallium(III) chloride in a novel tandem cycloisomerization/Friedel-Crafts reaction. A section dedicated to the study on GaCl3-catalyzed alkyne hydration is also provided.Chapter III begins with a description of the synthesis of a series of gallium(III) complexes bearing various NHCs as ligands in order to overcome the limitations of gallium(III) halides in catalysis. Next, methodology studies on the tandem process involving 1,6-arenynes with the neutral and cationic gallium(III) complexes are described. The evaluation of scission kinetics for catalysts, substrates variation and influence of counteranions are discussed. In addition, efforts towards the asymmetric version of this tandem transformation and some other cyclizations are also presented.The concluding chapter reiterates the most important results obtained in the body chapters of the thesis. To conclude, the future directions for the research on the use of the NHC-gallium(III) complexes are discussed
Gojon, Sophie. "Carbènes N-hétérocycliques : nouvelle méthode de synthèse et activité catalytique pour la réticulation de silicone". Toulouse 3, 2011. http://www.theses.fr/2011TOU30321.
Texto completo da fonteThe main objective of this thesis is to study the synthesis of N-heterocyclic (NHCs) and their catalytic activity toward silicone elastomer formation
Darari, Mohamed. "Synthèse et caractérisation de nouveaux complexes Fe-NHC applicables en cellule solaire DSSC". Electronic Thesis or Diss., Université de Lorraine, 2019. http://www.theses.fr/2019LORR0318.
Texto completo da fonteThis thesis is part of a current concern and high interest research field, which is the development of new photoactive complexes using abundant metals to replace noble metals in renewable energy devices. Novel families of potential sensitizers for DSSC (Dye-sensitized solar cells) based on iron and tridentate pyridyl-carbene ligands (FeNHC) have been prepared and characterized. The aim, besides the application aspect for energy, is to increase the understanding of the structure-property relationships in Fe-NHC homoleptic complexes carrying pyridyl-bisimidazolylidene ligands by modification of the central core, anchoring group and coordination geometry. Once synthesized, the complexes were submitted to various photophysical, electrochemical and theoretical characterizations. A new MLCT excited state lifetime record was obtained with a pyrazine-based complexes (32 ps). The geometric optimization, which means the design of ligands to obtain an ideal octahedral coordination geometry to induce a strong ligand field was studied. X-ray diffraction measurements attested that the desired complexes were obtained by increasing the distance between the pyridine core and the lateral carbenes. This modification induces a bathochromic shift, but the electronic conjugation as well as the rigidity of the complexes remain to be optimized further. We have also developed a novel synthetic route for introducing Π-extended anchoring groups in order to limit the charge recombination after the injection into the TiO2 semiconductor. The efficiency of the DSSC cells was optimized by the incorporation of a new MgI2 additive in the electrolyte composition which led to an unprecedented efficiency of 0.5% for an iron complex. Finally, this thesis offers new synthetic tools for the design of FeII-NHC complexes with extended excited state lifetimes and represents a further step in the understanding of the photophysical processes operated within this type of iron complexes
Savchuk, Mariia. "Complexes atropisomériques d'or-NHC : design, synthèse et applications dans des réactions de cycloisomérisation asymétriques". Electronic Thesis or Diss., Aix-Marseille, 2022. http://www.theses.fr/2022AIXM0571.
Texto completo da fonteThe first chapter of this manuscript is dedicated to survey the design of chiral NHC and their applications as ligand in gold-catalyzed enantioselective transformations. This presentation clearly showed the importance of new ligand designs, because only poor enantioselectivities have been reached up to date. A new concept of atroipsomeric transition metal-NHC complexes has been devised and developed in our group. Its application to prepare chiral transition metal complexes bearing C1-symmetric NHC ligand containing a satured backbone was investigated during my Ph.D. work and will be presented in the second chapter. Various chiral complexes were obtained, separated by chiral HPLC at preparative scale and their configurational stabilities were investigated in depth. The gold (I) containing complex was tried in the 1,6-enyne cycloisomerization, giving a promissing enantioselectivity (70% ee). In the third chapter of this manuscript, the concept of atroipsomeric transition metal-NHC complexes was extended to C2-symmetric NHC ligands and applied to the asymmetric Au(I)-catalyzed transformations. Diisopropyl malonate-tethered 1,6-enynes were identified as excellent substrates for cycloisomerization reactions and resulting alkoxycyclization products were isolated with excellent enantiopurities (7 examples with 51-92% yield, 56-99% ee). The cyclization without external nucleophiles led also to excellent results a (6 examples with 72-99% yield, 86-93% ee)
Hussein, Hiba. "Synthèses de nouveaux ligands carbènes à structures N-hétérocycliques et macro-N-Bis-hétérocycliques symétriques et dissymétriques. Études de leurs propriétés photophysiques, biologiques et de coordination". Electronic Thesis or Diss., Université de Lorraine, 2022. http://www.theses.fr/2022LORR0014.
Texto completo da fonteThe objective of this thesis is to prepare new photosensitive molecules of N-heterocyclic carbenes, ligands or complexes, designed to meet the criteria of photosensitizers (PS) (pure, water-soluble, biocompatible, non-toxic molecules, with maximum absorbance efficiency, possessing good photophysical properties) applicable in the field of materials and/or in the biomedical field such as phototherapy. The ambition is to optimise the spectroscopic properties of the photosensitisers and to obtain a good photoactivity. This thesis describes in a first chapter a non-exhaustive state of the art concerning heterocyclic macrocycles, N-heterocyclic carbenes (NHC) and NHC macrocycles as well as a reminder of the expected properties of photosensitive molecules. In a second chapter, it details the syntheses of original N-heterocyclic and N-bis-heterocyclic bis-imidazolium ligands of open or closed macrocyclic structures as well as their physicochemical characterizations (infrared, NMR, mass spectroscopy). Crystallographic structures of some of these macrocycles were obtained by X-ray diffraction. In a third and final chapter, the various tests for the formation of carbenes and the study of their complexation properties towards transition metals are detailed. Theoretical Gaussian calculations are used to support this study. A fluorescence and singlet oxygen production study as well as an evaluation of the biological properties of the previously presented flexible macrocycles and ligands show promising photophysical and biological properties. In addition, an interesting preliminary study of the proton/deuterium exchange of carbon protons of bis-imidazolium macrocycles is described.Keywords: NHC, macrocyclic ligands, bipyridine, bithiazole, imidazolium, photosensitiser, photoactivity, anti-bacterial properties
Schnee, Gilles. "Synthèse et réactivité de nouveaux complexes des métaux du groupe 13 portés par des ligands carbènes N-hétérocycliques". Thesis, Strasbourg, 2012. http://www.theses.fr/2012STRAF053/document.
Texto completo da fonteAt the beginning of this work, few studies had been performed on the complexation of N-heterocyclic carbenes with oxophilic metals, in high oxidation states such as group 13 metals. The synthetic routes optimization has extended the number of complexes-type NHC-MIII (M = aluminum, gallium and indium), and the corresponding cationic complexes. The combination of these precursors with sterically congested NHCs allowed the observation of unprecedented reactivities (abnormal complexes, Frustrated Lewis Pairs, N-heterocyclic dicarbenes). In a second step, the unusual reactivity of NHC ligands has allowed the isolation of analogues of the Tebbe’s reagent, formed to be very active in the methylenation of carbonyl compounds
Garrison, Jered C. "Silver N-Heterocyclic Carbenes". University of Akron / OhioLINK, 2005. http://rave.ohiolink.edu/etdc/view?acc_num=akron1124128998.
Texto completo da fonteMcMullon, Max William. "Exploiting anionically-tethered N-heterocyclic carbene complexes for small molecule activation". Thesis, University of Edinburgh, 2018. http://hdl.handle.net/1842/31079.
Texto completo da fonteFauché, Kévin. "NHC portant des azotures : intermédiaires dans la synthèse catalysée d‘hétérocycles polyazotés et auto-fonctionnalisation de complexes métal-NHC". Thesis, Université Clermont Auvergne (2017-2020), 2018. http://www.theses.fr/2018CLFAC062/document.
Texto completo da fonteN-heterocyclic carbenes (NHC) are widely used to complex transition metals. They rarely leave their role as ancillary ligand and find, since 20 years, applications in catalysis or, more recently, in medicinal chemistry. In this work, we will discuss a mild synthetic method leading to the formation of AgI – NHC complexes via a soluble silver species. This method allowed us to obtain well known complexes but also to access a new series of NHC-Ag-phosphine complexes. We will also present a new reaction where NHC ligands bearing an azide function close to the carbenic center leave their role as ancillary ligand and lead to the formation of nitrogen rich heterocycles by a carbene-nitrene cyclization. This reaction will be presented in detail, along with the spectroscopic characterization regarding a sub-series of fluorescent compounds obtained by this method. Finally, we will present a post-functionalization strategy of complexes developed in our team. Silver(I)-NHC complexes tagged by an azide close to the carbenic center catalysed their own functionalization. Moreover, copper(I) complexes tagged by an azide function in a distant position from the metallic centre will be grafted on magnetic nanoparticles to act as recyclable catalysts
Durmus, Semih. "Silver(I) and Gold(I) N-Heterocyclic Carbene Complexes". University of Akron / OhioLINK, 2006. http://rave.ohiolink.edu/etdc/view?acc_num=akron1165247084.
Texto completo da fonteMasoud, Salekh. "New olefin metathesis catalysts with fluorinated NHC ligands : synthesis and catalytic activity". Thesis, Rennes 1, 2017. http://www.theses.fr/2017REN1S136/document.
Texto completo da fonteAn efficient approach to a new family of unsymmetrical 1,3-bis(aryl)-4,5-dihydroimidazolium salts comprising bulky hexafluoroisopropylmethoxy group in para- or ortho-position in one of the N-aryl substituents has been developed. New imidazolinium salts with fluoroalkyl-containing mono-ortho-aryl substituent at one of the nitrogen atom have also been synthesized. It was found that these imidazolinium salts are effective NHC precursors and provided an efficient access to a series of new ruthenium carbene complexes with unsymmetrical fluorinated NHC ligands. The method involves in situ generation of the carbene via treatment of the starting salts with potassium hexamethyldisilazide and subsequent ligand exchange reaction with PCy3-containing first generation Grubbs and Hoveyda complexes. The catalytic activity of the new complexes has been investigated on model reactions of intra- and intermolecular olefin metathesis. It was found that most of the synthesized complexes exhibited high activity in cyclization of diethyl diallylmalonate and in cross metathesis of allyl benzene with 1,3-diacetoxybut-2-ene. Their performance has proved to be comparable with commonly used second generation Grubbs and Hoveyda catalysts, with sometimes some differences in the initiation step. Structural and electronic impact of fluorinated unsymmetrical NHC on reactivity of new ruthenium complexes has been studied. In particular, it was revealed that Hoveyda type catalysts with mono-ortho-aryl substituted NHC ligands have demonstrated very high initiation rate in CM reactions. On the contrary, catalysts with more donating N-alkyl NHCs have displayed low activity; for instance, the N-tert-butyl substituted complex has proved to be absolutely inert both in RCM and CM reactions. Symmetrical ruthenium carbene complexes bearing NHC ligands with two hexafluoroisopropylmethoxy group in para-positions of N-aryl moieties are significantly inferior in reactivity with respect to their asymmetric counterparts showing the strong influence of the desymmetrization factor on catalytic activity
Baffert, Mathieu. "Synthesis of ruthenium complexes having one or more N-heterocyclic carbene ligands supported on hybrid mesostructured silicas and their use in the hydrogenation of carbon dioxide". Phd thesis, Université Claude Bernard - Lyon I, 2011. http://tel.archives-ouvertes.fr/tel-00838661.
Texto completo da fontePinaud, Julien. "Catalyse organique par les carbènes N-hétérocycliques (NHCs) et leur version supportée sur polymères à des fins de recyclage". Thesis, Bordeaux 1, 2010. http://www.theses.fr/2010BOR14135/document.
Texto completo da fonteN-Heterocyclic carbenes (NHCs) have been employed as organic catalysts for the step-growth polymerization of terephtaldehyde. This part is an application to polymer chemistry of the so-called “benzoin condensation”, reaction catalyzed by NHCs involving a mono-aldehyde substrate. Poly(1,4-phenylene-1-oxo-2-hydroxyethylene)s or « polybenzoins » have thus been obtained by polymerization reactions conducted in DMSO or THF at temperatures below 40°C. Presence of cyclic polybenzoins has been put forward. The content of such cyclic species was found to vary as a function of the NHC catalyst employed and of the reaction media used. In a second part, simple solutions have been proposed to easily handle NHCs, by avoiding their degradation. For this purpose, polymer supports bearing NHCs moities, i.e “poly(NHC)s”, have been developed and employed for the purpose of organocatalysis. Even if “poly(NHC)s” were found to be recyclable, they still remain sensitive to impurities. Another way to protect the carbenic centers is to react “poly(NHC)s” with CO2. The adducts thus obtained, “poly(NHC-CO2)s”, can then be employed as precursors for the in situ generation of “poly(NHC)s”, by a simple thermal activation. A further carboxylation of such generated species allow for the recovering of “poly(NHC-CO2)s”. Finally, synthetic methods for the preparation of imidazolium (molecular version) and polyimidazolium (supported polymer version) salts with hydrogenocarbonate (HCO3-) as counter-anion have been developed. Such precursors can serve as precatalysts (molecular or supported) to generate, by heating, NHCs and poly(NHC)s, giving a practice way to conduct organocalysed reactions and recycle the catalysts
Gibard, Clémentine. "Synthèse, fonctionnalisation et applications de métallo-NHC du groupe 11". Thesis, Clermont-Ferrand 2, 2014. http://www.theses.fr/2014CLF22519/document.
Texto completo da fonteN-heterocyclic carbenes (NHCs) have been used very frequently as ligands for the preparation of transition metal-based catalysts as well as drug candidates. This work will present a simplification of imidazoliniums synthesis and a new preparation of Ag-, Cu-NHC complexes. Aqueous ammonia will be used for the solubilisation of metallic species and as a base for the deprotonation of imidazoli(ni)um salts providing a mild, quick and easy metallation procedure. The functionalisation of NHC ligands, in definite positions, allows the modulation of some of their characteristics without interfering with the remarkable properties of their complexes. New functionalisation strategies by azide-alkyne cycloaddition reaction at the periphery of aromatics cores, were developped. This can be described by the following three synthetics strategies: pre-, post- and auto-functionalisation. Pre-functionnalisations strategy of precursors allows the synthesis of coinage metal-NHC complexes, for which variation of solubility is easily obtained. Thermal Huisgen reactions and SPAAC are achievable on the Au-NHC azide modified complexes directly, in a post-functionalisation pathway. Furthermore, the post-functionnalisation strategy was extended to Cu-NHC complexes resulting in an auto-functionalisation process. This allowed subsequently the introduction of sensitive biomolecules without protection/deprotection steps. Finally, water soluble Cu-NHCs complexes were used as CuAAC catalyst in bio-compatible media. Lipophilic Ag-NHCs complexes were tested as antibacterials (antibiofilm and growth inhibition activities)
Saker, Oliver John. "Mono- and tri-nuclear ruthenium complexes incorporating N-heterocyclic carbene ligands". Thesis, University of Bath, 2008. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.512305.
Texto completo da fonteMakhlouf, Brahmi Malika. "Réactivité des complexes carbènes N-hétérocycliques-boranes (NHC-Boranes)". Paris 6, 2010. http://www.theses.fr/2010PA066480.
Texto completo da fonteN-heterocyclic carbenes boranes (NHC-Boranes) complexes are novel structures whose reactivity —especially organic— has not been explored. Our goal was to investigate the influence of the NHC complexation on the reactivity at the boron atom. We focused first on radical reactions. Computational studies showed that the values of the B-H BDE of these complexes are low enough to use them as radical hydrogen donors in the Barton-McCombie deoxygenation of xanthates. We thus reported that two NHC-BH3 complexes reduce different secondary xanthates in acceptable yields under the Barton-McCombie conditions. Then, we found that palladium could mediate the reduction of a variety of aryl halides and triflates by using NHC-boranes complexes as an hydride donors. In addition, we found that, by changing the borane, palladium could catalyze sp2–sp2 and sp2–sp3 C–C couplings in good to excellent yields. NHC-boranes complexes are hence a family of new boron partners for Suzuki-Miyaura couplings. Finally, we discovered a new reactivity by generating a borenium cation stabilized by the NHC ligand. This reactivity allows us to synthesize fluorinated NHC-boranes complexes
Paradiso, Veronica. "Ruthenium metathesis precatalysts with unsymmetrical Nheterocyclic carbene (NHC) ligands". Doctoral thesis, Universita degli studi di Salerno, 2018. http://hdl.handle.net/10556/3017.
Texto completo da fonteOlefin metathesis is one of the most important chemical transformations for the formation of carbon-carbon double bonds. The possibility to build up highly funtionalised alkenes starting from simple olefins makes this reaction indispensable in modern organic synthesis, giving access to a wide range of molecules that would be barely obtained through other synthetic routes. The success of metathesis is due to the development of new and efficient catalysts which can be used in a wide variety of research fields, both in industry and in academia. In this context, the research of the ‘perfect’ metathesis complex still impassions scientists all over the word, and several research papers regarding the development of new catalytic systems are published every year. The group I am part of focuses its attention on the development of new ruthenium metathesis catalysts. Our interest lies in the influence that nature and configuration of substituents on the N-heterocyclic carbene (NHC) ligand could have on the performances of the corresponding metal complexes. In this doctoral thesis, the field of unsymmetrical N-heterocyclic carbene (u-NHC) ruthenium catalysts will be explored. Synthesis and characterisation of several novel complexes will be discussed. Catalytic performances will be evaluated in model metathesis reactions as well as in more attractive metathesis transformations. The relationship between NHC structure and complexes’ behaviours will be investigated using NMR, X-Ray, IR, cyclic voltammetry and DFT calculations. ..[edited by Author]
XXX ciclo
Kelly, Roy A. III. "New Metal-NHC Complexes: Synthesis, Characterization, and Uses". ScholarWorks@UNO, 2014. http://scholarworks.uno.edu/td/1817.
Texto completo da fonteEllul, Charles. "Trimetallic N-heterocyclic carbene complexes". Thesis, University of Bath, 2011. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.538279.
Texto completo da fonteLi, Kai, e 李凯. "Photoluminescent organoplatinum (II) complexes containing N-heterocyclic carbene (NHC) ligands". Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2013. http://hub.hku.hk/bib/B50533915.
Texto completo da fontepublished_or_final_version
Chemistry
Doctoral
Doctor of Philosophy
Medici, Fabrizio. "Interactions entre les Spirosilane de Martin et Base de Lewis coordination, frustration et nouveau ligand anionique". Thesis, Paris Sciences et Lettres (ComUE), 2017. http://www.theses.fr/2017PSLET029.
Texto completo da fonteThis thesis work is focused on the reactivity of Martin’s Spirosilane, a molecule that displays some interesting properties in particular with different Lewis base, founding some interesting application such us fluoride sensor. In our study, we have chosen N-Heterocyclic Carbene (NHC) because they are well known for stabilising low-valence states of p-block elements or for disclosing new reactivities. Besides, NHC are known to form relatively stable adducts with tetravalent halosilanes and also to stabilise silicon(0) species through potassium graphite reductions, but, to the best of our knowledge, no pentacoordinated NHC-adducts with a non-halogenated silane partner has been synthesised to date.The first part of my PhD was focused on the update of Martin’s spirosilane synthesis due to some problem of reproducibility with the known procedure. Once obtained the product, it was begun the investigation of the interaction with different NHC carbene that afforded the corresponding adducts that were fully characterised. The different adducts were then studied as potential Frustrated Lewis Pair and as precursors of anionic-type ligands for the metal's coordination
Hameury, Sophie. "Oxygen-functionalized NHC ligands and their nickel(II), silver(I) and palladium(II) complexes". Thesis, Strasbourg, 2014. http://www.theses.fr/2014STRAF010.
Texto completo da fonteThe purpose of this work was the synthesis of complexes bearing O-functionalized NHC ligands in order to test their catalytic properties in ethylene oligomerization. In order to have access to alcohol-functionalized complexes, the corresponding silver complexes were synthesized for transmetallation purpose. Whereas no concluding results were obtained with the alcohol function in association with nickel, it was possible to access an alcoholate-functionalized NHC ligand by deprotonation of the corresponding pro-ligand. Thus, polynuclear nickel complexes were prepared, some of them included in their structure a lithium cation originating from the base. For comparison, alcohol- and alcoholate-functionalized NHC palladium complexes were synthesized by direct reaction of the pro-ligand with Pd(acac)2 followed by acidobasic reactions. Because of the complexity of the chemistry of NHC-alcohol ligands associated with nickel, the ether functionality was explored. A library of nickel complexes was synthesized and tested in the catalytic ethylene oligomerization
Marr, Isobel Helen. "Synthesis and reactivity of scandium N-heterocyclic carbene complexes". Thesis, University of Edinburgh, 2014. http://hdl.handle.net/1842/17970.
Texto completo da fonteGeraghty, Paul Bythell. "Studies towards the synthesis of fused N-Heterocyclic carbene precursors". Thesis, University of Canterbury. Chemistry, 2013. http://hdl.handle.net/10092/8197.
Texto completo da fonteRobinson, William J. III. "Development of Tetrathiafulvalene Fused N-Heterocyclic Carbene Compounds". Wright State University / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=wright1610382201476554.
Texto completo da fonteFlahaut, Alexandre. "Utilisation de complexes carbènes N-hétérocyclique-palladium dans la réaction de Tsuji-Trost et dans la réaction umpolung d'allylation de dérivés carbonylés". Paris 6, 2008. http://www.theses.fr/2008PA066149.
Texto completo da fonteFahlbusch, Tilmann. "Supramolekulare N-heterocyclische Carben Liganden: Synthese, Charakterisierung und Anwendung von Übergangsmetall-NHC-Calix[4]aren-Komplexen". [S.l. : s.n.], 2006. http://nbn-resolving.de/urn:nbn:de:bsz:289-vts-57999.
Texto completo da fonteVallet, Anne-Laure. "Réactivités de NHC-Boranes Soufrés". Thesis, Paris 11, 2014. http://www.theses.fr/2014PA112261.
Texto completo da fonteAlong with the development of green chemistry, it became necessary to avoid toxic metallic complexes in organic reactions and replace them by more sustainable compounds. An hydrogen donors for radical reactions, trialkylstannanes are still widely used. NHC-boranes seem to be good substitutes for deoxygenation reactions. However, dehalogenation reactions are less effective and polar reversal catalysis was used. This work was the starting point of this Ph.D thesis where the synthesis of new NHC-boranes bearing a B-S or B-N bound is developed. The study of the properties of these new complexes was performed and applications in organic chemistry as well as in polymer science were found. Besides, to study polar effects on the formation and on the reactivity of boryl radicals, a new family of carbene-boranes was synthesized
Chou, Yajie. "Complexes de palladium-NHC atropisomériques : design, synthèse et applications en catalyse asymétriques". Electronic Thesis or Diss., Ecole centrale de Marseille, 2022. http://www.theses.fr/2022ECDM0012.
Texto completo da fonteThe performances of palladium-based catalysts in various cross-coupling reactions have attracted an ever-growing attention since the seventies and the development of enantioselective versions was the subject of intensive research. In this field, monodentate auxiliary N-heterocyclic carbene (NHCs) ligands possessing robust σ-donating and adaptable π-accepting properties confer to the metal excellent reactivities. NHCs ligands are referred as smart ligands, because their electronic and steric properties can be finely tuned to specific catalytic transformations. Therefore, chiral NHC-Pd complexes are a class of chiral catalysts that have developed rapidly in the recent decades. Nevertheless, new catalysts with enhanced reactivity and enantioselectivities are required as only few applications are actually developed in the industry. The goal of my Ph.D. was the investigated of a new design of chiral NHC-Pd complexes and their application to explore new catalytic transformations. The first chapter is focused on carbene chemistry as ligands of transition metals with main achievements reported in the literature. Chemical properties of NHCs have been also reviewed. In this chapter, the different designs of chiral NHC ligands for palladium-based catalysis reported in the literature as well as their applications in enantioselective catalysis have been also surveyed. Finally, previous studies on chiral NHC-palladium complexes in our laboratory are presented in order to define the objectives and issues of my Ph.D. work. In the second chapter of this manuscript, we analyze the advantages and disadvantages of the catalysts developed in our group, with the goal of simplifying the synthesis steps and improving the catalytic activity. As a result, some novel NHC-Pd complexes with axial chirality were designed and synthesized by known synthetic methods. The synthesized C2-symmetric NHC-Pd complexes were first attempted to separate diastereomers by silica gel column chromatography to remove meso compounds. Subsequently, heterochiral complexes were resolved in enantiomerically pure form by preparative-scale chiral HPLC. Finally, the catalytic reactivity and enantiomeric inductions of these highly enantiomerically pure chiral NHC-Pd catalysts were evaluated in the benchmark reaction: α-amide arylation of amides. Up to good chiral inductions were reached.In the third chapter, novel palladium-catalyzed transformations were investigated and developed with the new chiral Pd-NHC complexes previously established in the laboratory. After the optimization of reaction conditions and the screening of several catalysts, we found that these new catalysts can achieve good chiral induction in the α-arylation of ketones. We also tried NHC-Pd catalyzed hydrogenation, although the reaction did not lead to noticeable results. Kumada coupling reactions were also studied to synthesize planar-chiral metacyclophanes. Various chiral metacyclophanes have been prepared and their configurational stabilities have been investigated. Finally, optimal reaction conditions have been identified allowing to carry this asymmetric reaction with good results in terms of both reactivity and enantioselectivity
Garmendia, Sofiem. "Synthesis of new N-Heterocyclic Carbene (NHC)-based Single Chain Nanoparticles (SCNPs) as catalytically active nanoreactors". Thesis, Bordeaux, 2020. http://www.theses.fr/2020BORD0009.
Texto completo da fonteRandom copolymers based on poly(ionic liquids) have been developed under different architectures such as single chain nanoparticles (SCNPs) or as (macro)gels. Those different systems have been employed as N-heterocyclic carbenes (NHCs) precurors to be used as organocatalysts. The incorporation of relatively basic counteranions in PIL units derived from imidazolium moieties allows the in situ generation of active NHC species for catalysis. Firstly, a reactive PIL based (macro)gel represents the preliminary study to better understand and analyse the catalytic performance in the macroscale. This study has permitted the identification of suitable model reactions as well as conditions and standards, becoming a reference system all along this thesis. Moreover, this (macro)gel has served as a base for the further development of more sophisticated nanogels known as single chain nanoparticles (aka SCNPs). These SCNPs have specially been designed based on their PIL tunability and synthesised by reversible additions fragmentation chain transfer (RAFT) polymerisation. In first place, the ionic nature of the NHC precatalyst was exploited by triggering the interaction between imidazolium derivatives and basic anions supported in the polymer leading to a ionically cross-linked SCNP. Secondly, the thermolatent properties of NHC precursors was harnessed by proving the compatibility of both substrates and precatalyst supported on the same polymer chain and triggering the folding by condensing the substrates by the simple application of heat. Finally, the intrinsic capacity of poly(NHC)s to act as poly-ligands was innovatively demonstrated by forming SCNPs after organometallic complexation using a silver salt. Overall, the different polymeric supports have served to highlight different aspects related to the catalytic performance of supported catalysts such as recycling, confinement effect, nanoreactor scaling up processes, NHC catalysts versatility as well as the adaptability of these systems for enabling and easy and efficient handling and storage
Resch, Stefan Günter. "Dinuclear Copper and Nickel Complexes of New Multidentate N-heterocyclic Carbene Ligands: Structures, Dynamics and Reactivity". Doctoral thesis, Niedersächsische Staats- und Universitätsbibliothek Göttingen, 2018. http://hdl.handle.net/21.11130/00-1735-0000-0005-12D5-6.
Texto completo da fonteDe, Fremont Pierre. "Synthesis of Well-Defined N-Heterocyclic Carbene (NHC) Complexes of Late Transition Metals". ScholarWorks@UNO, 2008. http://scholarworks.uno.edu/td/829.
Texto completo da fonteFrémont, Pierre de. "Synthesis of well-defined N-heterocyclic carbene (NHC) complexes of late transition metals". Le Mans, 2007. http://cyberdoc.univ-lemans.fr/theses/2007/2007LEMA1010.pdf.
Texto completo da fonteThis dissertation is dedicated to the synthesis of well-defined organosilver and organogold complexes bearing NHC ligands. In addition, two short chapters describe briefly the synthesis of NHC acetylacetonate palladium(II) complexes, and the use of NHC ruthenium(II) indenylidene complexes in ring opening metathesis polymerization reactions. New silver(I) and gold(I) halide mono-NHC complexes are synthesized, structurally characterized, and compared to other existing silver(I) and gold(I) complexes. The gold(I) cation firmly bound to the carbene, undergoes oxidative addition with halogens to afford gold(III) NHC complexes, or dehalogenation in presence of inorganic silver salts to afford cationic gold(I) mono-NHC complexes in coordinating solvent. The coordinating solvent can be replaced by a neutral or anionic group to yield gold(I) NHC complexes with unusual ligands such as olefins, pyridines, sugars. In contrast, the silver(I) cation is weakly bound to the carbene, and silver(I) NHCs decompose in presence of halogens or inorganic silver salts
Frémont, Pierre de Fontaine Laurent Nolan Steven. "Synthesis of well-defined N-heterocyclic carbene (NHC) complexes of late transition metals". [S.l.] : [s.n.], 2007. http://cyberdoc.univ-lemans.fr/theses/2007/2007LEMA1010.pdf.
Texto completo da fonteThèse soutenue en co-tutelle. Titre provenant de l'écran-titre.
Boschetti, Riccardo. "Synthesis of novel N-heterocyclic carbene precursors for new chiral complexes". Master's thesis, Alma Mater Studiorum - Università di Bologna, 2018. http://amslaurea.unibo.it/16665/.
Texto completo da fonteLi, Dazhi. "Synthesis and Applications of Novel Chiral NHC Precursors. Synthesis of Urea Derivatives through Decomposition of Cu-NHC under Air. Iron-mediated Synthesis of Dihydroquinoxalinones". Doctoral thesis, Université Laval, 2019. http://hdl.handle.net/20.500.11794/37234.
Texto completo da fonteSince its first isolation, N-heterocyclic carbenes (NHC) have been found very useful to coordinate with metals and serve as ligand in catalysis. With the advantages of environmental friendliness, abundance and being less expensive, iron as a metal catalyst has received growing attention in recent decades. Despite that many Fe-NHCs have been synthesized, chiral Fe-NHC for asymmetric catalysis is still in its infancy. In comparison to precious metals, copper as a versatile and less expensive transition metal also has recieved much attention. However, the development of chiral Cu-NHC as efficient catalyst is still challenging. Thus, several types of novel chiral NHC ligand precursors have been synthesized. The synthesis of chiral Fe-NHCs and Cu-NHCs were attempted using those chiral precursors. It was found that the Fe-NHCs and Cu-NHCs would decompose under air. On the other hand, the applications of in situ generated generated chiral Fe-NHCs and Cu-NHCs were carried out for hydrosilylation reactions, Mukaiyama aldol reactions, insertion of metal-carbene into SiH bond and Heck-type reactions. The in situ generated Fe-NHCs were found not applicable in the hydrosilylation of acetophenone. For the Mukaiyama aldol reactions, the conditions using in situ generated Fe-NHCs led to the desired products in up to 88% yield. However, no enantioselectivity was observed for all attempts, probably due to the deactivation of NHC ligand. The insertion reaction of metal-carbene into SiH bond catalyzed by in situ generated Cu-NHCs afforded up to 84% yield and 24% ee of product. Besides, the Heck-type reactions were tested using a chiral Pd-NHC as catalyst. The reactions afforded up to 91% yield, but no enantioselectivity was observed. Furthermore, the decompositions of different types of Cu-NHCs and Ag-NHCs in solutions under humid air were studied. The Cu-NHCs underwent hydrolysis and oxidation to generate imidazoliums and urea derivatives under air. The Ag-NHCs were hydrolyzed to yield formamides or imidazoliums in solution under humid air. Subsequently, a new synthetic method of urea derivative using copper and air as oxidant was developed, which provided moderate to very good yields for sterically unhindered substrates. The mild oxidation conditions are suitable for the synthesis of urea derivatives possessing alkyl, benzyl, aryl, primary hydroxy, acid-sensitive tertbutyloxycarbonyl group, and tertiary amine groups. In the last project, a general and efficient synthesis of enantiopure dihydroquinoxalinones has been developed. The reductive cyclization of N-(o-nitroaryl)amino esters was performed by using iron and zinc metal under mild conditions to afford dihydroquinoxalinones in moderate to high yields and high enantiomeric purity.
Mahjoor, Parisa. "Synthetic, Structural and Thermochemical Studies of N-Heterocyclic Carbene (NHC) and Tertiary Phosphine Ligands in the Ni(CO)2(L)x (L-PR3, NHC) Systems". ScholarWorks@UNO, 2004. http://louisdl.louislibraries.org/u?/NOD,165.
Texto completo da fonteTitle from electronic submission form. "A thesis ... in partial fulfillment of the requirements for the degree of Master of Science in the Department of Chemistry."--Thesis t.p. Vita. Includes bibliographical references.
Fernández, Álvarez Álvaro. "Drug-containing NHC-Gold complexes for biomedical applications". Thesis, Toulouse 3, 2018. http://www.theses.fr/2018TOU30148.
Texto completo da fonteMalaria is the most important parasitic infection in people, threatening around 40% of the human population. In the last years it has become a bigger public health concern because of the augmentation of malaria parasites resistant to artemisinin and its derivatives. Some NHC-gold(I) complexes show antimalarial activities, being a very promising alternative in malaria treatment because of their potential to inhibit thioredoxin reductase (TrxR) that plays a major role in mitochondrial respiratory chain (one of the two pathways that remains active in the quiescent state of the resistant parasites). In this work of thesis a panel of drug-NHC-gold(I) complexes including artemisinin and triclosan moieties has been synthesized and characterized with the objective of developing hybrid molecules with a dual mode of action able to overcome plasmodium resistance to artemisinin and its derivatives. The first group of molecules concerns a family of aliphatic or aromatic-functionalized cationic bis-NHC-gold(I) and neutral mono-NHC-gold(I) complexes with an artemisinin moiety connected through an aliphatic linker. The group includes three series depending on the length of the aliphatic linker (C3, C4, and C5). The three series have been tested against the sensible F32-TEM strain of P. falciparum showing high activities with IC50 values in the nM range. The second group concerns a series of aliphatic or aromatic-functionalized bis-NHC-gold(I) complexes with an triclosan moiety connected through an aliphatic linker. Triclosan inhibits the fatty acid synthesis pathway, which also remains active in the quiescent state on resistant parasites. These complexes were tested against P. falciparum showing, high activities with IC50 values in the nM range. The ligands of this series and their respective complexes have been also tested against one of the leishmaniosis causing parasites, L. infantum, being very effective in both, amastigote and promastigote forms, with IC50 values in the low µM range
Kascatan, Nebioglu Aysegul. "N-HETEROCYCLIC CARBENE SILVER(I) COMPLEXES FROM XANTHINES AND THEIR ANTIMICROBIAL APPLICATIONS". University of Akron / OhioLINK, 2007. http://rave.ohiolink.edu/etdc/view?acc_num=akron1176579309.
Texto completo da fonteWright, Brian D. "Synthesis, Characterization, and Biological Activity of Silver Carbene Complexes and Their Precursors". University of Akron / OhioLINK, 2012. http://rave.ohiolink.edu/etdc/view?acc_num=akron1353423024.
Texto completo da fonteReddy, Y. S. V. "Enantioselective construction of six - membered heterocycles and carbocycles using N - heterocyclic carbene (NHC) - organocatalysis". Thesis(Ph.D.), CSIR-National Chemical Laboratory, Pune, 2016. http://dspace.ncl.res.in:8080/xmlui/handle/20.500.12252/2079.
Texto completo da fonteGuitet, Maxime. "Fonctionnalisation des cols primaire et secondaire de l’alpha-cyclodextrine et études de complexes NHC-cyclodextrines-métaux". Paris 6, 2013. http://www.theses.fr/2013PA066507.
Texto completo da fonteTwo aspects of the cyclodextrins (CDs) chemistry were studied. On one hand two new methods of functionalization were developed. First using iodine and triethylsilane the 3 position of polybenzylated CDs could be selectively deprotected. Second, based on the known DIBAL-H reactivity in the lab and preventing the AD reactivity, an unprecedented ACE triol was obtained. A kinetic study enlightened the mechanism, showing the existence of two intermediate diols converging to the triol. Furthermore, this strategy was combined to the known tandem debenzylation/azido reduction to afford deoxy amino-diols CDs. On the other hand, CD-NHC-Metals (NHC=N-Heterocyclic Carbene) hybrid complexes were synthesized. Two NHCs were introduced on A and D positions of the primary rim of perbenzylated and permethylated α-CDs and the corresponding PdII complexes prepared. These complexes were used in Suzuki cross-coupling. Then, after capping the CD in AD with a NHC, the AgI, CuI and AuI complexes were obtainded. A structural study evidenced the position of the metal inside the cavity, inducing original C-H…M, C-H…X et π…X interactions, confirmed by ligand exchange experiments. Finally, the gold complex show good activity in cycloisomerisation, even affording enantioselectivity
Messori, Alessandro. "Bidentate N-heterocyclic carbene complex of Manganese as catalyst for hydrosilylation and hydroboration of double and triple bonds". Master's thesis, Alma Mater Studiorum - Università di Bologna, 2020. http://amslaurea.unibo.it/21666/.
Texto completo da fonteFyfe, Andrew Alston. "d- and f-metal alkoxy-tethered N-heterocyclic carbene complexes". Thesis, University of Edinburgh, 2016. http://hdl.handle.net/1842/15862.
Texto completo da fontePearson, Stephen. "High oxidation state carbene complexes for C-H bond activation catalysis". Thesis, University of Edinburgh, 2010. http://hdl.handle.net/1842/7570.
Texto completo da fonteGómez, Suárez Adrián. "Synthesis and reactivity studies of mono- and diaurated species bearing N-heterocyclic carbene ligands". Thesis, University of St Andrews, 2014. http://hdl.handle.net/10023/6546.
Texto completo da fonteSantoro, Orlando. "Copper(I)-N-heterocyclic carbene (NHC) complexes : synthesis, characterisation and applications in synthesis and catalysis". Thesis, University of St Andrews, 2016. http://hdl.handle.net/10023/8409.
Texto completo da fonte