Дисертації з теми "Palladium - N - heterocyclic carbene"
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Ellul, Charles. "Trimetallic N-heterocyclic carbene complexes." Thesis, University of Bath, 2011. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.538279.
Повний текст джерелаArentsen, Katherine. "Application of palladium N-heterocyclic carbene complexes in catalysis." Thesis, University of Sussex, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.430951.
Повний текст джерелаDiebolt, Olivier. "N-heterocyclic carbene ligands in palladium and iridium organometallic chemistry." Thesis, University of St Andrews, 2010. http://hdl.handle.net/10023/2126.
Повний текст джерелаTitcomb, Lisa Rae. "Novel palladium N-heterocyclic carbene complexes as catalysts for aminations." Thesis, University of Sussex, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.395012.
Повний текст джерелаGallop, Christopher W. D. "N-heterocyclic carbene-palladium and -copper complexes in cross-coupling reactions." Thesis, University of Sussex, 2015. http://sro.sussex.ac.uk/id/eprint/54338/.
Повний текст джерелаZinser, Caroline Magdalene. "Palladium and gold N-heterocyclic carbene complexes : synthesis and catalytic applications." Thesis, University of St Andrews, 2019. http://hdl.handle.net/10023/17066.
Повний текст джерелаSprick, Reiner Sebastian. "Polytriarylamines containing fused ring and heterocyclic structures prepared using N-heterocyclic carbene complexes of palladium." Thesis, University of Manchester, 2013. https://www.research.manchester.ac.uk/portal/en/theses/polytriarylamines-containing-fused-ring-and-heterocyclic-structures-prepared-using-nheterocyclic-carbene-complexes-of-palladium(c09188eb-490b-452c-945a-22979f58c76d).html.
Повний текст джерелаKirian, Lewis Alexandra Katharine de. "Synthesis and catalytic applications of nickel and palladium N-heterocyclic carbene complexes." Thesis, University of Sussex, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.424203.
Повний текст джерелаGuest, Daniel P. "Synthesis of novel N-heterocyclic carbene-palladium complexes and their catalytic activity." Thesis, University of Sussex, 2017. http://sro.sussex.ac.uk/id/eprint/68087/.
Повний текст джерелаNavarro-Fernandez, Oscar. "Synthesis, Activation and Catalytic Activity of N-Heterocyclic Carbene Bearing Palladium Catalysts." ScholarWorks@UNO, 2006. http://scholarworks.uno.edu/td/330.
Повний текст джерелаSCATTOLIN, THOMAS. "Palladium organometallic compounds bearing N-Heterocyclic Carbene ligands as promising anticancer agents." Doctoral thesis, Università degli Studi di Trieste, 2019. http://hdl.handle.net/11368/2938813.
Повний текст джерелаGupta, Sumanta. "Synthesis of palladium - N - heterocyclic carbene complexes and their application in organic transformations." Thesis, University of North Bengal, 2014. http://ir.nbu.ac.in/handle/123456789/1853.
Повний текст джерелаBoschetti, 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/.
Повний текст джерелаRose, Marcus, Andreas Notzon, Maja Heitbaum, Georg Nickerl, Silvia Paasch, Eike Brunner, Frank Glorius, and Stefan Kaskel. "N-Heterocyclic carbene containing element organic frameworks as heterogeneous organocatalysts." Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2014. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-138636.
Повний текст джерелаDieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG-geförderten) Allianz- bzw. Nationallizenz frei zugänglich
Rose, Marcus, Andreas Notzon, Maja Heitbaum, Georg Nickerl, Silvia Paasch, Eike Brunner, Frank Glorius, and Stefan Kaskel. "N-Heterocyclic carbene containing element organic frameworks as heterogeneous organocatalysts." Royal Society of Chemistry, 2011. https://tud.qucosa.de/id/qucosa%3A27766.
Повний текст джерелаDieser Beitrag ist mit Zustimmung des Rechteinhabers aufgrund einer (DFG-geförderten) Allianz- bzw. Nationallizenz frei zugänglich.
Lerma, Israel Consea. "Transformations Mediated by Palladium-(N-Heterocyclic)Carbenes Complexes." Thesis, University College London (University of London), 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.498701.
Повний текст джерелаMartínez, Lombardía Alberto. "Heterogenized n-heterocyclic carbene metal complexes for selective catalysis." Doctoral thesis, Universitat Rovira i Virgili, 2016. http://hdl.handle.net/10803/386577.
Повний текст джерелаLa presente tesis doctoral se centra en el desarrollo de catalizadores que permitan llevar a cabo procesos sintéticos de manera más eficiente y sostenible. Se presentan dos nuevas familias de catalizadores soportados, ambas pertenecientes al grupo de complejos organometálicos moleculares inmovilizados sobre un soporte sólido. La primera familia incluye complejos de Pd con ligandos carbeno N-heterocíclico monodentados de gran impedimento estérico, inmovilizados sobre óxidos inorgánicos, como sílicas, alúmina u òxido de titanio. Esta familia de catalizadores se aplicó en dos tipos de reacciones: i) reacciones de acoplamiento C-C y ii) semireducción de alquinos. Entre las reacciones de acoplamiento mencionadas, los complejos de [Pd(NHC)] inmovilizados se aplicaron en las reacciones de Suzuki, Heck y Sonogashira, y se evaluaron en base a su actividad, selectividad y reciclabilidad. Además, en el caso de las reacciones de Suzuki y Sonogashira, estos catalizadores también se aplicaron en condiciones de flujo continuo. La aplicación de esta familia de catalizadores en la semireducción selectiva de alquinos se llevó a cabo utilizando dos metodologías diferentes: utilizando hidrógeno molecular, o bien utilizando el sistema trietilamina/ácido fórmico como dador de H (condiciones de transferencia de hidrógeno). La segunda familia de catalizadores soportados contempla complejos de Rh(I) estabilizados con ligandos bidentados de tipo carbeno N-heterocíclico, con quiralidad axial, y funcionalizados con un grupo pireno. La inmovilización de estos complejos de Rh sobre la superficie de nanotubos de carbono "multi-walled" tuvo lugar mediante interacciones de tipo "pi-pi stacking" entre la superficie de los nanotubos y el grupo pireno presente en el ligando. Finalmente, se presentan los resultados obtenidos en la aplicación de estos complejos de Rh en varios procesos catalíticos.
The present PhD thesis aims at contributing to the development of more efficient and sustainable synthetic processes through catalysis. In this regard, two families of new solid-supported catalysts are presented. Both families belong to the group of molecularly defined organometallic complexes immobilized onto a solid support. The first family includes Pd complexes of sterically hindered monodentate N-Heterocylic Carbene ligands supported onto inorganic oxide materials, namely silicas, alumina and titania. This family of catalysts was applied in two types of reactions: i) C-C cross-couplings and ii) semireduction of alkynes. Among cross-coupling reactions, the supported [Pd(NHC)] complexes could be applied in Suzuki, Heck and Sonogashira couplings and their performance was assessed in terms of activity, selectivity and reusability. For the Suzuki and Sonogashira couplings, the catalysts were also appied under continuous flow conditions. The application of this family of catalysts in the selective reduction of alkynes was carried out following two different methodologies: using hydrogen gas, or using triethylamine/formic acid as the H-donor system (transfer hydrogenation conditions). The second family of solid-supported catalysts features Rh(I) complexes bearing axially chiral bidentate N-Heterocyclic carbene ligands functionalized with a pyrene moiety. Immobilization of these Rh complexes onto the surface of multi-walled carbon nanotubes was achieved by means of "pi-pi stacking interactions" between the surface of the nanotubes and the pyrene moiety present in the ligand. Results obtained from the application of these complexes as catalysts in various reactions are presented.
Haque, Rosenani S. M. Anwarul. "Silver, mercury and ruthenium complexes of N-heterocyclic carbene linked cyclophanes." University of Western Australia. Chemistry Discipline Group, 2008. http://theses.library.uwa.edu.au/adt-WU2008.0236.
Повний текст джерелаSilcock, Peter J. "Nickel and palladium complexes of di-N-heterocyclic carbenes." Thesis, University of Oxford, 1999. https://ora.ox.ac.uk/objects/uuid:679dade4-1d16-4918-b155-996250516783.
Повний текст джерелаSchmid, Thibault E. "Synergism between N-heterocyclic carbene and phosphorus-based ligands in ruthenium and palladium catalytic systems." Thesis, University of St Andrews, 2012. http://hdl.handle.net/10023/3452.
Повний текст джерелаMalineni, Jagadeesh [Verfasser]. "N-Heterocyclic Carbene Palladium Pincer Complexes: Synthesis, Aggregations and Catalytic Applications / Malineni Jagadeesh. Mathematisch-Naturwissenschaftliche Fakultät." Bonn : Universitäts- und Landesbibliothek Bonn, 2011. http://d-nb.info/1017567905/34.
Повний текст джерелаEsposito, Oriana. "Mechanistic and kinetic studies on aryl and alkyl amination reaction catalysed by palladium n-heterocyclic carbene complexes." Thesis, University of Sussex, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.487117.
Повний текст джерелаAnsell, Melvyn B. "Novel (N-heterocyclic carbene)-palladium(0) complexes as catalysts in element-element bond additions to unsaturated moieties." Thesis, University of Sussex, 2017. http://sro.sussex.ac.uk/id/eprint/68072/.
Повний текст джерелаClement, Nicolas David Stephane. "Zero valent n-heterocyclic carbene complexes of nickel, palladium and platinum : synthesis, structure, reaction chemistry and catalysis." Thesis, Cardiff University, 2005. http://orca.cf.ac.uk/55984/.
Повний текст джерелаPearson, Stephen. "High oxidation state carbene complexes for C-H bond activation catalysis." Thesis, University of Edinburgh, 2010. http://hdl.handle.net/1842/7570.
Повний текст джерелаDeetlefs, Maggel. "Carbene and coordination complexes of gold, palladium, platinum and manganese derived from N-containing heterocycles." Thesis, Stellenbosch : Stellenbosch University, 2001. http://hdl.handle.net/10019.1/52155.
Повний текст джерелаMarion, Nicolas. "N-heterocyclic carbenes as supporting ligands in homogeneous catalysis." Doctoral thesis, Universitat Rovira i Virgili, 2008. http://hdl.handle.net/10803/9031.
Повний текст джерелаpopularity, notably as highly versatile ligands for transition metals. Their strong -donating
properties, associated with high steric hindrance, often impart enhanced stability and activity to a given metallic center. Two main successes of the NHCs in homogeneous catalysis are arguably the ruthenium-mediated olefin metathesis and the palladium-promoted crosscoupling reactions.In this work, we have studied the effect of N-heterocyclic carbenes as supporting ligands in well-defined complexes of palladium(II), gallium(III), and gold(I) that we used in homogeneous catalysis.Notably, we have synthesized, in very straightforward manners, two families of palladium compounds of formulae [(NHC)Pd(L)Cl], where L, which is a R-allyl or R-acac moiety, acts as a protecting shell for the catalytically active [(NHC)Pd0] species. Hence,
upon activation under the reaction conditions, these new Pd complexes were found extremely active in the Suzuki-Miyaura, the Buchwald-Hartwig, and the -ketone arylation cross-coupling reactions. More precisely, the more active "R-allyl family" allowed for reactions to be performed with as low as 10 ppm of palladium.
A series of [(NHC)GaCl3] complexes wa synthesized via a simple one-step procedure. The resulting unprecedented NHC-GaIII compounds were found extremely stable but showed only moderate activity in isomerization reactions.Demonstrating further the versatile application of NHCs in metal-based catalysis, we
developed several new catalytic transformations using [(NHC)AuCl] complexes. Hence,these pre-catalysts, activated in situ with a silver salt, proved to be excellent activators of
alkynes, allenes, and alkenes. This led to the development of efficient synthetically useful
protocols, encompassing enyne cycloisomerization, indene cyclization,formation of conjugated enone, and allylic rearrangement.
KEYWORDS gallium - gold - homogeneous catalysis - N-heterocyclic carbene - palladium 8
En los últimos diez años, los carbenos N-heterocíclicos (NHCs) han ganado una gran
popularidad, especialmente como ligandos versátiles de metales de transición. Su fuerte
carácter −donor, asociado con su gran impedimento estérico, confieren a menudo una
mayor estabilidad y actividad al centro metálico en cuestión. Los dos mayores éxitos de los
NHCs en catálisis homogénea se encuentran, sin duda, en la metátesis de olefinas catalizada
por rutenio y en las reacciones de acoplamiento cruzado promovidas por paladio.
En este trabajo, hemos estudiado el efecto de los carbenos N-heterocíclicos como
ligandos en complejos bien definidos de paladio(II), galio(III) y oro(I), que hemos empleado
en catálisis homogénea.En particular, hemos sintetizado, de forma directa, dos familias de compuestos de paladio de fórmula general [(NHC)Pd(L)Cl] donde L, grupo R-alilo o R-acac, actúa como protector para las especies catalíticamente activas [(NHC)Pd0]. De hecho, tras la activación
en las condiciones de reacción, estos nuevos complejos de paladio se mostraron extremadamente activos en las reacciones de Suzuki-Miyaura, de Buchwald-Hartwig y en la -arilación de cetonas. Más concretamente, la 'familia R-arilo', más activa, permitió llevar a cabo estas reacciones con tan sólo 10 ppm de paladio.Una serie de complejos [(NHC)GaCl3] fue preparada en una simple etapa. Los compuestos resultantes NHC-GaIII, sin precedentes en la literatura, se mostraron extremadamente estables pero sólo moderadamente activos en reacciones de isomerización.Con el fin seguir ampliando la gran aplicabilidad de los NHCs en catálisis con
metales, estudiamos varias nueva transformaciones utilizando los complejos [(NHC)AuCl].De hecho, estos pre-catalizadores, activados in situ con una sal de plata, demostraron ser excelente activadores de alquinos, alenos y alquenos. Esto llevó al desarrollo de protocolos eficientes, y sintéticamente útiles, tales como la cicloisomerización de eninos, la ciclación de
indenos, la formación de enonas conjugadas, y reordenamientos arílicos.
Aksın, Özge Artok Levent. "The activity of silica immobilized palladium N-heterocyclic carbene complexes toward Mizoro-Heck reaction and their characterization/Özge Aksın;thesis advisor Levent Artok." [s.l.]: [s.n.], 2005. http://library.iyte.edu.tr/tezler/master/kimya/T000341.pdf.
Повний текст джерелаKeywords: Palladium, Immobilization, Heck Reaction, Palladium-N-Heterocyclic Carbene, Carbon-Carbon Coupling. Includes bibliographical references (leaves. 89-104).
Smith, Christopher. "Computational studies of alkene hydrophosphination with platinum catalysts and proton-assisted ligand substitution in functionalised N-heterocyclic carbene dimethyl palladium complexes." Thesis, Heriot-Watt University, 2007. http://hdl.handle.net/10399/88.
Повний текст джерелаSingh, Rohit. "Development of N-Heterocyclic Carbenes as Organic Catalysts and Efficient Ligands in Palladium Mediated Transformations." ScholarWorks@UNO, 2007. http://scholarworks.uno.edu/td/576.
Повний текст джерелаHung, Faan-fung, and 孔繁峰. "Luminescent platinum(II), palladium(II) and gold(III) complexes containing isocyanide, alkynyl and N-heterocyclic carbene ligands : synthesis, photophysical properties and material applications." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2014. http://hdl.handle.net/10722/206318.
Повний текст джерелаHameury, Sophie. "Oxygen-functionalized NHC ligands and their nickel(II), silver(I) and palladium(II) complexes." Thesis, Strasbourg, 2014. http://www.theses.fr/2014STRAF010.
Повний текст джерелаThe 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
Ren, Hui. "Synthèses, caractérisation et étude structurale de complexes de type carbènes N-hétérocycliques basés sur des Calix[4]arènes." Thesis, Lyon 1, 2014. http://www.theses.fr/2014LYO10315.
Повний текст джерелаThis thesis will focus on development of N-heterocyclic carbene palladium complexes based on calix[4]arenes: from synthesis, characterization and structural study to evaluation of catalytic activity. A new series of calix[4]arene supported N-heterocyclic carbene palladium complexes was developed and fully characterized. A mono-substituted calix[4]arene was prepared through conventional procedures, following with the attachment of imidazolyl derivative groups to compose the precursors of novel NHCs ligands. Undergoing the alkylation with n-butylbromide and corresponding metallation with palladium and pyridine, original complexes were obtained. After a full characterization in solution and solid state, the evaluation of catalytic activity was undertaken through Suzuki-Miyaura cross-coupling reactions which revealed good performances. The conformational study as well as the catalytic results in catalysis did not allow putting in evidence a supramolecular effect of the macrocycle cavity towards the coupling process. With the aim of localize catalytic center inside of the cavity, steric constrain was involved in the form of new Pd-NHC-complexes. Dimeric Pd complexes were synthesized and fully characterized as well. Several approaches to construct intramolecular linkers for fixing the conformation were elaborated. The conception of ‘flexible steric bulky’ inspired the research on confined structure of calix[4]arene, such as encapsulation and capped configuration. Relative progresses were carried out and discussed
Kong, 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.
Повний текст джерелаN-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)
Lesieur, Mathieu. "Cu and Pd complexes of N-heterocyclic carbenes : catalytic applications as single and dual systems." Thesis, University of St Andrews, 2015. http://hdl.handle.net/10023/7999.
Повний текст джерелаLefebvre, Jean-François. "Synthèse et propriétés de ligands de type carbène N-hétérocyclique conjugués à une porphyrines." Thesis, Montpellier 2, 2010. http://www.theses.fr/2010MON20141/document.
Повний текст джерелаIn addition to the usual inner coordination site of porphyrins, it is possible to functionalize the macrocycle by external coordination sites. This PhD thesis is devoted to the functionalization of two neighboring b-pyrrolic carbons in order to obtain porphyrins fused to peripheral N-heterocyclic carbene ligands (NHC).NHC ligands are known to display outstanding electronic properties which render them important ligands in the fields of catalysis and organometallic chemistry. The aim of this PhD work was to study the influence of the porphyrin on the electronic properties of the peripheral NHC ligand, and to modulate the electronic and catalytic properties of anchored metal complexes according to the chemical modifications brought to the porphyrin, ie. its metallation or the protonation of the free-base porphyrin.Firstly, the different synthetic procedures to obtain porphyrins fused to imidazolium rings were developed. These imidazolium salts are the key precursors of the porphyrin-NHC ligands. In order to study the catalytic properties of metal complexes containing porphyrin-NHC ligands, several palladium(II) complexes were synthesized and characterized. The study of the catalystic properties of these complexes showed that better catalytic activities were observed if the porphyrins contain a metal cation. Then, the electronic properties of these NHC ligands were evaluated for (NHC)Rh(COD)X and (NHC)Rh(CO)2X complexes with X = I or Cl
Craft, Derek T. "Palladium and Gold-Catalyzed transannular [4+3] cycloaddition reactions: Application to the ABCD carbon framework of Cortistatin A. A short synthesis of S-(+)-Siphonodiol. New chiral Au(I) N-heterocyclic carbene complexes and their use in intramolecular c." Oxford, Ohio : Miami University, 2010. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=miami1272036117.
Повний текст джерелаMartínez, Agramunt Víctor. "Nickel and palladium supramolecular organometallic complexes based on NHC-ligands with polyaromatic moieties for host-guest chemistry studies." Doctoral thesis, Universitat Jaume I, 2020. http://dx.doi.org/10.6035/14104.2020.366143.
Повний текст джерелаThree nickel-based and one palladium-based supramolecular organometallic cages have been prepared. These four cages are based on a N-heterocyclic carbene ligand with a pyrene tag, that has been key in the subsequent applications of the cage together with the inner cavity. By pi-stacking interactions, it has been possible to encapsulate both polycylic aromatic hydrocarbons and fullerenes. The interest on first group of compounds is based on their accurate toxicity while the fullerenes are interesting due to their added value. It was possible to extract the first group of molecules from an organic media through the encapsulation inside the supramolecular cages. The host-guest adduct formed with fullerenes encapsulated inside the palladium cage was used as photocatalyst of aromatic, cyclic and acyclic substrates via singlet oxygen generation. The same palladium cage was used as receptor for multiple stacks of polyaromatic compounds.
Programa de Doctorat en Ciències
Almallah, Hamzé. "Systèmes confinants pour la catalyse homogène." Thesis, Strasbourg, 2019. http://www.theses.fr/2019STRAF011.
Повний текст джерелаDescribed herein are the stepwise syntheses and properties of three types of complexes based on sterically encumbered N-heterocyclic carbenes (NHCs): 1) Pd-PEPPSI complexes with an unsymmetrical imidalolylidene ligand having its N atoms substituted by a bulky 9-alkyl-9-fluorenyl (AF) group and an aryl group. These turned out to be very active Suzuki-Miyaura cross coupling catalysts with an activity comparable to previously reported, highly performing "symmetrical" analogues which bear two identical AF substituents. These findings illustrate the high stabilising effect of each individual AF group; 2) Trigonal copper(I) complexes with the general formula [Cu(Im)(2,2'-dipyridylamine)]BF4 in which the NHC ligands are symmetrical or not. Here again the AF substituents ensure complex stability with respect to air when compared to analogues displaying sterically non-bulky substituents. One of the complexes, namely [Cu((EtF,Ph)-Im)(2,2'-dipyridylamine)]BF4, was found to be strongly luminescent in solution and in the solid state; 3) Pd-PEPPSI complexes in which calix[4]arene-substituted phenyl moieties have been grafted on both N atoms, these behaving as potential receptor units. Owing to the presence of the calixarene termini, complexes of this type were found to self-assemble, thereby resulting in dimers with sterically highly protected metal centres. The formation of such species was correlated to the catalytic performance of these complexes
Buscemi, Gabriella. "Functionalisation of aromatic C-H bonds with dicarbene transition metal catalysts." Doctoral thesis, Università degli studi di Padova, 2009. http://hdl.handle.net/11577/3426071.
Повний текст джерелаIl presente progetto di ricerca riguarda l’applicazione di complessi dicarbenici di metalli di transizione in reazioni di funzionalizzazione/attivazione di legami C-H aromatici. L’efficienza catalitica di questi complessi è stata principalmente valutata nella reazione di idroarilazione di alchini (reazione di Fujiwara), che consiste nell’addizione di areni ad alchini interni o terminali catalizzata da semplici composti di palladio(II), come Pd(OAc)2. Questa reazione decorre in ambiente acido, generalmente acido trifluoroacetico, a temperatura ambiente e presenta una elevata ed inusuale regio- e stereoselettività: si ottengono infatti come prodotti principali i cis-arilalcheni, che sono le olefine termodinamicamente meno favorite. La reazione appare molto promettente dal punto di vista tecnologico, anche perché sono conosciute sia la versione inter- che quella intramolecolare, permettendo quindi la funzionalizzazione di eterocicli aromatici e la sintesi di cumarine. La potenziale applicazione industriale richiede però l'ottimizzazione delle condizioni di reazione, poichè la reazione è spesso lenta, necessita di un eccesso di arene rispetto all’alchino e viene condotta con un elevato tenore di catalizzatore (1-5%), fattore che incide pesantemente sul costo del processo. Altri centri metallici, come Pt(II), Au(I) e Au(III), sono stati impiegati come catalizzatori alternativi, ma la loro reattività sembra essere inferiore a quella mostrata dai composti di palladio(II). Sono stati utilizzati anche centri metallici elettrofilici non nobili, ma la loro reattività è inferiore e/o la loro applicabilità limitata ai soli aril-acetileni. L’obiettivo iniziale di questo progetto di tesi è stato quindi quello di migliorare le rese della reazione e diminuire il tenore di catalizzatore. Leganti carbenici N-eterociclici possono aumentare la stabilità del catalizzatore nelle condizioni di reazione e quindi la sua reattività. I complessi monocarbenici di palladio(II), (IPr)Pd(OAc)2 e (IPr)Pd(OOCCF3)2 (IPr = N,N’-bis(2,6-diisopropylphenyl)-imidazol-2-ylidene) sono infatti gli unici complessi ad essere risultati attivi nella reazione di Fujiwara senza bisogno di promotori, sebbene la loro reattività sia comparabile a quella mostrata da Pd(OAc)2. Nella prima parte di questo lavoro di ricerca è stato dimostrato che complessi dicarbenici di palladio(II) catalizzano la reazione ad 80 °C, con eccellenti conversioni e selettività a basso tenore di catalizzatore (0.1%) e con i reagenti in rapporto equimolare. Questi complessi hanno mostrato una reattività maggiore rispetto al semplice palladio acetato ed al complesso monocarbenico (12) testati nelle stesse condizioni di reazione. Sono stati impiegati in questo studio anche complessi dicarbenici di Pt(II), che si sono dimostrati più attivi dei sistemi catalitici di platino riportati in letteratura. Il protocollo ottimizzato è risultato abbastanza generale per quanto riguarda gli alchini, mentre la sua applicabilità agli areni è al momento limitata a molecole elettron-ricche. Questa è comunque una limitazione di tutti i sistemi catalitici di Pd e Pt riportati in letteratura per l’idroarilazione di alchini. Una seconda parte del lavoro ha riguardato l’identificazione della specie cataliticamente attiva. Studi meccanicistici condotti ad 80 °C, variando sia il legante dicarbenico che i leganti anionici al metallo, hanno mostrato che la specie cataliticamente attiva mantiene il legante dicarbenico nella sua sfera di coordinazione, mentre i leganti anionici vengono rimossi dal complesso attraverso uno scambio con l’anione trifluoroacetato derivante dal solvente acido. L’efficienza catalitica del complesso non dipende dal tipo di leganti anionici, ma dipenda invece dalla natura del legante dicarbenico. Sono stati inoltre effettuati studi elettrochimici per determinare la densità elettronica presente al centro metallico in complessi con diverso legante dicarbenico, con lo scopo di chiarire se l’efficienza del complesso sia principalmente influenzata dalle proprietà elettroniche o da quelle steriche di questo legante e di progettare così il migliore catalizzatore per la reazione. Le voltammetrie cicliche hanno mostrato che la densità elettronica al centro metallico varia a seconda del legante dicarbenico, ma che la scala di potenziali di riduzione Pd(II)-Pd(0) non è correlabile alla scala di attività catalitica. L’efficienza di questo tipo di complessi nella reazione di Fujiwara sembra quindi essere principalmente influenzata dall’ingombro sterico al centro metallico. La successiva ottimizzazione dei parametri di reazione (natura del solvente, concentrazione dei reagenti, temperatura di reazione ed utilizzo di co-catalizzatori) ha permesso di incrementare ulteriormente la selettività della reazione in condizioni di reazione blande. E’ stato infatti dimostrato che in presenza di sali di argento come co-catalizzatori (per esempio AgTFA) la reazione avviene anche a temperatura ambiente, con conversioni maggiori di quelle ottenute con palladio acetato nelle stesse condizioni di reazione. Diversamente che a 80 °C, le reazioni di isomerizzazione a trans-arilalchene (prodotto più stabile termodinamicamente) e le reazioni di idrolisi delle funzioni esteree non avvengono a temperatura ambiente, cosicché la selettività verso il cis-arilalchene viene notevolmente migliorata. Infine, sono state determinate le condizioni sperimentali adatte per estendere questo protocollo sintetico ad eterocicli aromatici, ottenendo anche in questo caso elevate rese nei prodotti. La selettività della reazione verso il prodotto desiderato è però diminuita dalla formazione di addotti eterociclo/alchino 2/1. Analisi preliminari di tipo cinetico hanno inoltre dato una prima indicazione sul tipo di meccanismo coinvolto nella reazione, che non è ancora del tutto chiarito e che potrebbe coinvolgere la metallazione elettrofilica dell’arene oppure una alchenilazione di tipo Friedel-Crafts. La legge cinetica è risultata essere del primo ordine in palladio e, nelle particolari condizioni dei reazione adottate, anche del primo ordine in arene o in alchino. Rimane da valutare la dipendenza della legge cinetica dalla concentrazione di acido, che sembra avere un ruolo importante nel meccanismo di reazione. Deve essere infatti utilizzato in largo eccesso rispetto ai substrati e probabilmente il suo ruolo principale è quello di idrolizzare la specie vinilica di palladio, proposta come intermedio catalitico in entrambi i cicli riportati in letteratura. I complessi dicarbenici di palladio(II) e platino(II) sono stati testati anche in altre reazioni di funzionalizzazione di legami C-H aromatici, come l’orto-funzionalizzazione di acetanilidi.
Gerdin, Martin. "Silaborations of Unsaturated Compounds." Doctoral thesis, Stockholm : Chemical Science and Engineering, Kungliga Tekniska högskolan (KTH), 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-9440.
Повний текст джерелаCasely, Ian J. "Electropositive metal N-heterocyclic carbene complexes." Thesis, University of Edinburgh, 2009. http://hdl.handle.net/1842/3873.
Повний текст джерелаRodden, Mark. "Alkoxide functionalised N-heterocyclic carbene complexes." Thesis, University of Nottingham, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.423306.
Повний текст джерелаWilliamson, Craig. "Imidazolylidenes in N-heterocyclic carbene organo-catalysis." Thesis, University of Aberdeen, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.440601.
Повний текст джерелаTulloch, Arran Alexander Dickon. "Novel mixed donor N-Heterocyclic carbene complexes." Thesis, University of Southampton, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.249941.
Повний текст джерелаBemowski, Ross David. "Novel N-heterocyclic dicarbene ligands and molybdenum and dimolybdenum N-heterocyclic carbene complexes." Diss., University of Iowa, 2013. https://ir.uiowa.edu/etd/1291.
Повний текст джерелаCollinson, John Michael. "Immobilised N-heterocyclic carbene metal complexes in catalysis." Thesis, Imperial College London, 2014. http://hdl.handle.net/10044/1/42227.
Повний текст джерелаChardon, Edith. "N-Heterocyclic carbene complexes : toward innovative anticancer agents." Strasbourg, 2011. http://www.theses.fr/2011STRA6265.
Повний текст джерелаAmong the existing anticancer agents, cisplatin or cis-diamminedichloroplatinum(II), represents the most known and commonly used chemotherapeutic drug worldwide highlighting the potential of metals in medicinal chemistry. However, its clinical effectiveness is also accompanied by severe side toxicities and cell-resistance mechanisms. These therapeutic limitations have encouraged the development of substitutes to cisplatin and have led to the discovery of N-heterocyclic carbene (NHC) complexes of several late transition metals as new anticancer agents with similar to higher in vitro activities than cisplatin. In this context, the present project dealt with the synthesis and the study of novel cytotoxic NHC complexes of some transition metals (mainly platinum). Two simple, reproducible and modular synthetic routes were developed for the easy functionalization post-complexation of NHC derivatives using (a) ruthenium-catalyzed alkyne-azide cycloaddition and (b) ligand substitution. In order to improve the efficacy and selectivity of the NHC complexes, we have extended these strategies of functionalization to the attachment of biologically interesting moieties such as targeting agents, hydrosoluble groups and fluorescent dyes. In vitro cytotoxic activities of these newly synthesized complexes were measured against a wide variety of cancerous cells. The majority of the compounds demonstrated higher activities than the benchmark cisplatin and some were selective toward tumoral cells. These promising early-stage results offer new perspectives in cancer therapy while giving alternatives to the biomedical limitations of cisplatin
Robinson, 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.
Повний текст джерелаSerre, Veronique. "Synthesis of new N-heterocyclic carbene metal complexes." Thesis, Loughborough University, 2004. https://dspace.lboro.ac.uk/2134/34833.
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