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Holub, Jan. "Generation of coordination architectures from dynamic covalent ligand libraries." Thesis, Strasbourg, 2016. http://www.theses.fr/2016STRAF060/document.
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La Chimie Dynamique Combinatoire basée sur les liaisions imines (-C=N-), avec l’aide de la chimie de coordination, donne accès à différentes types d’architectures metallosupramoléculaires et de réseaux dynamiques fonctionnels. Le travail effectué au cours de cette thèse traite de ces deux aspects. Dans un premier temps des structures de types grilles moléculaire et de type hélicate ont été synthétisés, à l’aide de métaux donnant une coordination octahédrale ou tétraédrale, et leurs propriétés dans un environnement dynamique ont été étudiées. Dans un deuxième temps des réseaux dynamiques, présentant des relations agoniste/antagoniste à travers l’échange des constituants aldéhydes et amines/hydrazines réseau, ont été étudiés. Ces systèmes permettent, à travers l’amplification d’un ou plusieurs constituants, une rééquilibration du réseau permettant l’implémentation de fonction tel que l’apprentissage et la prise de décision pour ces systèmes chimiques adaptifs. Un nouveau système, est présenté et étudié ici, permettant une redistribution stable même après le retrait du stimuli métallique (ajout/retrait d’un métal), permettant à ce système de réaliser un processing d’information : apprentissage, stockage, rappel et effacementDynamic Combinatorial Chemistry of imine-based dynamic covalent bonds (-C=N-), under the governance of coordination chemistry, can lead to different metallosupramolecular architectures and responsive functional systems. In this work these two aspects have been approached. Grids and helicates architectures based on aldehydes and amines/hydrazines backbones have been synthesised, in order to probe their behaviour in a dynamic network environment, using both octahedral and tetrahedral coordinating metal cations. Dynamic systems can be also represented by dynamic networks that define agonistic and antagonistic relationships between different constituents linked through component exchange. These networks can be switched through amplification of the best fittest constituent(s) in a dynamic set, allowing to access higher level functions such as training, learning, and decision making for adaptive chemical systems. A novel multi responsive system, able to be trained for information storage, has been studied, exhibiting a stable distribution even after removal of the metal stimuli, making this system able to perform information processing operations: training, storage, recall, and erase
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Prema, Dipesh. "Different coordination modes of bis(imine-ridine) and bis(quinaldine) ligands." Diss., Manhattan, Kan. : Kansas State University, 2007. http://hdl.handle.net/2097/267.
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Barner, Claudia Jane. "Part I. Coordination chemistry of high-valent osmium polyanionic chelating ligand complexes with imine, imido and nitrido ligands. : Part II. Asymmetric hydrogenation using a resolved chiral scandium hydride complex /." Diss., Pasadena, Calif. : California Institute of Technology, 1990. http://resolver.caltech.edu/CaltechETD:etd-06112007-095040.
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Magee, Chad Leroy Keller S. W. "The synthesis and characterization of 1,1'-disubstituted ferrocene imine Schiff base ligand systems for use as potential environmental heavy metal cationic sensors." Diss., Columbia, Mo. : University of Missouri--Columbia, 2008. http://hdl.handle.net/10355/7117.
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Title from PDF of title page (University of Missouri--Columbia, viewed on Feb. 23, 2010). The entire thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file; a non-technical public abstract appears in the public.pdf file. Dr. Steven W. Keller, Dissertation Supervisor. Vita. Includes bibliographical references.
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Gunler, Zeynep Inci. "Synthesis Of N-(2-propylphenyl) Substituted Chiral Amino Alcohols And Their Usage In Enantioselective Diethylzinc Addition Reactions." Master's thesis, METU, 2011. http://etd.lib.metu.edu.tr/upload/12613001/index.pdf.
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Chiral 1,2-amino alcohols were synthesized via newly developed &ldquointramolecular unsaturation transfer&rdquo
using cyclohexanone, propargyl bromide, and various chiral amino alcohols as starting components. These amino alcohols can be potential chiral ligands for many asymmetric transformation reactions. Therefore, their effectiveness as chiral ligands in diethylzinc addition to benzaldehyde and N-diphenylphosphinoyl imines were tested. Various parameters including temperature, solvent, ligand amount etc. were screened for the synthesized chiral ligands. In diethylzinc addition to benzaldehyde high enantioselectivity could not be obtained. When N-diphenylphosphinoyl imines were used as substrate good ee values up to 80% were achieved.
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Pierre, Fabrice. "Synthese et reduction electrochimique de complexes (#5-cyclopentadienyl) (#6-arene) fer(ii)pf#6 porteurs d'une fonction imine ou nitrone en position benzylique du ligand arene." Rennes 1, 1997. https://tel.archives-ouvertes.fr/tel-00343810.
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Ce memoire rapporte une etude de fonctionnalisation de complexes (cp fe arene)#+, dans un cadre fondamental d'activation de liaison c-h benzylique par les metaux de transition. La condensation entre le (cp fe diphenylmethane)#+ et le nitrosobenzene ou les nitrosotoluenes, initiee par 5% de t-buok, conduit a des melanges de complexes (cp fe benzophenone-n-arylnitrones)#+ et (cp fe benzophenone-anils)#+ (env. 80:20) avec de bons rendements (80-92%. Les complexes nitrones sont obtenus purs par recristallisation fractionnee (rdt. 22-35%). La condensation de nitrosoarenes varies r-ph-no (r = h, 2-me, 3-me, 4-me, 2-cl, 4-cl, 2-ch#2co#2me, 3-come, 4-come, 4-nme#2) sur le complexe (cp fe fluorene)#+ donne exclusivement des cations imines (cp fe fluorenone-anil)#+ (rdt. 57-95%), isoles a l'etat de melanges syn-anti (env. 30:70). La meme reaction avec l'o-nitrosobenzoate de methyle fournit un melange imine-nitrone (60:40). En raison du caractere oxydant eleve du nitrosobenzene, nous n'avons pu le condenser sur d'autres cations (cp fe arene)#+ (arene = toluene, ethylbenzene, indane, tetraline et 9,10-dihydroanthrancene). L'hydrolyse acide de ces cations imines et nitrones a ete abordee d'un point de vue cinetique par polarographie. L'hydrolyse a l'echelle preparative permet d'obtenir les complexes (cp fe benzophenone)#+ et (cp fe fluorenone)#+ avec de bons rendements (respectivement 91 et 82%). La reduction electrochimique en milieu hydro-organique basique des melanges de (cp fe benzophenone-n-arylnitrones)#+ et (cp fe benzophenone-anils)#+ permet de synthetiser les amines correspondantes (cp fe--(arylamino)diphenylmethane)#+ avec de bons rendements (85-90%). Les cations (cp fe-9-(arylamino)fluorene)#+ sont obtenus de la meme maniere (rdt. 70-88%) en milieu hydro-organique acide, a partir des derives correspondants (cp fe -fluorenone anil)#+ ou la nitrone (cp fe fluorenone-n-(2'-methoxycarbonyl phenyl)nitrone)#+. D'apres l'etude des deplacements chimiques en rmn #1h, l'isometre exo est forme majoritairement pendant l'electrosynthese des complexes 9-(arylamino) fluorenes (exo:endo env. 75:25). Nous expliquons ce resultat inattendu par une epimerisation endo exo subsequente a la reduction. Ces complexes amines sont reoxydes par o#2 en imine de depart dans des conditions douces (catalyse par al#2o#3).
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Tanh, Jeazet Harold Brice. "Metallo-supramolecular Architectures based on Multifunctional N-Donor Ligands." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2010. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-39665.
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Self-assembly processes were used to construct supramolecular architectures based on metal-ligand interactions. The structures formed strongly depend on the used metal ion, the ligand type, the chosen counter ion and solvent as well as on the experimental conditions. The focus of the studies was the design of multifunctional N-donor ligands and the characterization of their complexing and structural properties. This work was divided into three distinct main parts: The bis(2-pyridylimine), the bis(2-hydroxyaryl) imine and the tripodal imine / amine ligand approach.
In the first part a series of bis(2-pyridylimine) derivatives having different linking elements were employed as building blocks for novel supramolecular architectures. Reaction of individual d-block metal salts with these ligands has led to the isolation of coordination polymers, a metallamacrocycle, double-stranded helicates, triple-stranded helicates as well as of circular meso-helicates. The nature of the spacer in the Schiff base ligands, the noncovalent weak interactions, such as hydrogen bond, face-to-face π-π and edge-to-face CH-π interactions, are all important factors influencing the architecture of the final products.
Topological control of the assembly process of the hexanuclear meso-helicates is clearly associated with the bidentate coordination of the sulfate anion which directs the formation of a double- rather than a triple-stranded helicate around the octahedrally coordinated Cu(II). Surprisingly, the variation of the linker function in the ligands, which significantly changes the linking angle of the pyridylimine strands, has only a little influence of the resulting structure. Also the use of a mixture of ligands does not influence the meso-helicate topology; the result is the symmetrically mixed meso-helicate.
The new iron(II) triple helicate [Fe2(L5)3](PF6)4 14 {L5 = bis[4-(2-pyridylmethyleneimino)phenyl]-1,1-cyclohexane} in its chloride form binds strongly to DNA as confirmed by induced circular dichroism signals in both the metal-to-ligand charge transfer (MLCT) and in-ligand bands of the helicate. The induced CD spectrum gives some evidence that [Fe2(L5)3]4+ interacts with the DNA in a single binding mode, which is consistent with major groove binding.
The cytotoxicity of the new iron(II) triple helicate 14 was evaluated on human lung cancer A549 cells and compared with that of cisplatin and that of the previously reported iron(II) triple helicate [Fe2(L1)3]4+{L1 = bis[4-(2-pyridylmethyleneimino)phenyl]methane}. The first results show some distinguishing features for 14 obviously caused by the existing structural differences of the complexes.
In the second part of the thesis, novel uranyl complexes of the bis(2-hydroxyaryl) imine ligands have been synthesized and characterized. 1D coordination polymers and mononuclear structures were formed. In all complexes a distorted hexagonal bipyramidal coordination geometry around the uranyl centre is observed. The imine nitrogen atoms of the ligands do not bind to the metal centre but interact strongly with the hydroxy group via H-bonding. DFT calculations made with L8 ( α,α’-Bis(salicylimino)-m-xylene) are in good agreement with the X-ray crystal structure data. Liquid-liquid extraction studies involving selected ligands and Eu(III) or U(VI) indicate remarkably high selectivity for U(VI) over Eu(III) at weak acidic pH conditions. We believe that the study made opens up new possibilities for uranyl ion extraction which could be interesting in view of the treatment of nuclear waste.
In the third part of the thesis, a series of multifunctional tripodal ligands with different N-donor centres were used for U(VI) and lanthanide, Nd(III), Eu(III) and Yb(III), binding and extraction. Reaction of these metal ions with selected tripodal ligands afforded complexes which were characterized by ESI mass spectroscopy. The complex composition was found to be 1:1 in all cases. The extraction behaviour of the tripodal ligands towards Eu(III) and U(VI) was studied both in the absence and presence of octanoic acid as co-ligand using the extraction system Eu(NO3)3 or UO2(NO3)2–buffer–H2O/ ligand–CHCl3. These separation systems show a remarkably high selectivity for U(VI) over Eu(III). It is interesting to note that the addition of the octanoic acid to the extraction system leads to high synergistic effects. A series of Eu(III) extraction experiments were done to clarify the composition of the extracted complexes. The results clearly point to the formation of various species with changing composition.
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Mukherjee, Soumen. "Transition metal complexes with imine-phenolate and imino-benzosemiquinone ligands synthesis, characterization, and their catalytic reactivity /." [S.l. : s.n.], 2003. http://deposit.ddb.de/cgi-bin/dokserv?idn=971568197.
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Wietzke, Raphaël. "Complexation des éléments par des ligands tripodes azotés : application à l'extraction sélective des actinides(III)." Université Joseph Fourier (Grenoble), 1999. http://www.theses.fr/1999GRE10223.
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Ce travail s'inscrit dans le cadre des recherches sur la separation actinides(iii)/lanthanides(iii) par extraction liquide-liquide. Nous nous sommes interesses a l'etude de la chimie de coordination des lanthanides(iii) et de l'uranium(iii) (modele des actinides(iii)), dans le but de mettre en evidence des differences entre les deux familles et de mieux comprendre les processus moleculaires impliques dans l'extraction. Nous avons ainsi etudie la complexation des lanthanides(iii) et de l'uranium(iii) par des ligands tripodes contenant des azotes aromatiques. Plusieurs ligands tripodes azotes ont ete synthetises en variant la nature et le nombre des atomes donneurs. Les complexes de lanthanides(iii) ont ete caracterises a l'etat solide et en solution (grace a differentes techniques : rmn 1h, es-ms, luminescence, spectrophotometrie uv, conductimetrie). Des differences dans le type de coordination ont pu etre mises en evidence selon la nature des atomes donneurs du ligand. Les deux nouveaux ligands, tris(2-pyrazinylmethyl)amine (tpza) et tris(n,n-diethyl-2-carbamoyl-6-pyridylmethyl)amine (tpaa), ont montre une selectivite pour les actinides(iii) avec des performances interessantes en extraction liquide-liquide. La comparaison des complexes de lanthane(iii) et d'uranium(iii) a l'etat solide et en solution a permis de mettre en evidence des differences dans la nature de la liaison qui pourraient etre attribuees a un certain pourcentage de covalence dans la liaison.
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Boudier, Adrien. "Design, synthesis and characterization of new ligands and activators for the oligomerization of ethylene by iron complexes." Phd thesis, Université de Strasbourg, 2012. http://tel.archives-ouvertes.fr/tel-00868786.
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This thesis describes the development of new catalytic systems based upon iron complexes and their reactivity toward ethylene. First, we focused our interest on the synthesis of iron(III) precursors chelated by monoanionic ligand. Those complexes were obtained either by reaction of the monoanionic ligand with FeCl3 or through oxidation of the iron(II) complex. The second reaction led to binuclear complexes. Then, another aim of the thesis was to design new well-defined cocatalysts for the activation of iron complexes. The study of the reaction between an alcohol and the trimethylaluminum allowed us to reach this aim. Aluminum complexes adopted either a binuclear framework or a trinuclear one, depending on the nature of alcohol reagent. Besides this work, new iron(II) and nickel(II) complexes chelated by imino-imidazole ligands bearing a pendant donor function L were synthesized. All complexes have been evaluated for the oligomerization of ethylene in the presence of EtAlCl2 or MAO as cocatalyst. Only nickel complexes were active toward ethylene transformation.
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Finn, Rachel Louise. "Studies on complexes of compartmental imine and amine ligands." Thesis, University of Nottingham, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.364648.
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Silva, Manuel Mateus Webba da. "Synthetic and spectroscopic studies on organometallic complexes of imine ligands." Thesis, University of Exeter, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.296312.
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Neshat, Abdollah. "Group V Imido Complexes Bearing Mono-Anionic Acetophenone Imine Ligands." University of Toledo / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1302269375.
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ROSAR, VERA. "The importance of ligand structural diversity in palladium catalyzed polymerization." Doctoral thesis, Università degli Studi di Trieste, 2016. http://hdl.handle.net/11368/2908017.
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Lo scopo principale della presente tesi di Dottorato è stato lo sviluppo di nuovi catalizzatori omogenei per la copolimerizzazione dell'etilene con monomeri vinilici polari, come gli esteri acrilici, al fine di ottenere poliolefine funzionalizzate contenenti una quantità controllata di monomero polare.
Il progetto di ricerca ha riguardato la sintesi e caratterizzazione di complessi di palladio(II) con nuovi leganti azotati non simmetrici di complessità via via crescente, appartenenti alla classe delle alfa-diimmine o a quella delle piridilimmine. Il comportamento catalitico dei complessi di palladio così ottenuti è stato studiato approfonditamente per la copolimerizzazione etilene/metil acrilato. Alcuni dei complessi sono stati testati quali catalizzatori anche per altre reazioni, come la copolimerizzazione CO/vinil arene e la doppia alcossicarbonilazione di alcheni, dimostrando la versatilità dei catalizzatori di palladio con leganti azotati.The main goal of the PhD research was the development of novel homogeneous catalysts for copolymerization of ethylene with polar vinyl monomers, such as acrylic esters, in order to obtain functionalized polyolefins with a controlled content of the inserted polar monomer. The project focused on the synthesis and characterization of palladium(II) complexes with novel non symmetric nitrogen-donor ligands of increasing complexity, and belonging either to the class of alpha-diimines or to the group of the pyridylimines. The catalytic behaviour of the synthesized palladium(II) complexes in the ethylene/methyl acrylate copolymerization was investigated in detail. Some of the catalysts were also applied to other reactions such as the CO/vinyl arene copolymerization and the bis-alkoxycarbonylation of alkenes, demonstrating the versatility of palladium catalysts with N-donor ligands.
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Hanton, Martin John. "Coordination complexes of bidentate phosphino-imine ligands : synthesis, characterisation and reactivity." Thesis, University of Leicester, 2003. http://hdl.handle.net/2381/33724.
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This thesis describes the synthesis, reactivity and coordination chemistry of a range of bidentate phosphino-imine ligands. The reactivity of the resultant complexes is also probed, while testing of the complexes for catalytic activity in a range of carbon-carbon bond-forming reactions is documented. Chapter 1 introduces the concepts of 'hemi-lability' and 'trans-influence', along with heteroditopic bidentate ligands, and specifically examines imine- and phosphine-based ligands, particularly aminophosphines. The nature of the phosphorus centre in terms of its steric and electronic properties is surveyed, and the bonding of phosphines and imines with metals is discussed. A review of transition metal-catalysed olefin oligomerisation and polyketone formation then follows. Finally, the aims of this work are outlined. Chapter 2 introduces the PNP ligand {(Pri2N)2PCH2C(=NPri)CH2P(NPri2)2}, previously synthesized within the Dyer group. The reactivity and coordination chemistry of this ligand are then explored, and the reactivity of the resultant complexes probed. The complex [PdCl(Me)(PNP)] has been crystallographically characterised. Chapter 3 briefly introduces guanidines, before describing the synthesis of two new types of phosphino-imine ligand derived from bicyclic and acyclic guanidines {R2P(TBD), R = Ph, Mes, Pri 2N, Ph2N and Ph2P(DMC), respectively}. The reactivity and coordination chemistry of these ligands is then explored, with particular attention paid to the effects of varying the substituents at phosphorus in R2P(TBD). The reactivity of the resulting complexes is then documented. The molecular structures of the ligands Ph2P(TBD), (Pri2N)2P(TBD) and Ph2P(DMC), and of twenty of their complexes have been determined. Chapter 4 describes the synthesis of the new P.;N ligand Ph2P(2-IP). The reactivity and coordinationchemistry of this ligand is then appraised, as is the reactivity of the resulting complexes. The structures of four complexes of this ligand have been probed crystallographically, as has a serendipitously formed nickel complex. Chapter 5 documents the catalytic testing conducted, using the complexes prepared in the chapters 2-4.
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Gerlach, Daniela. "Neuartige höherkoordinierte Siliciumkomplexe mit Pyrrol-2-carbaldimin-Liganden." Doctoral thesis, Technische Universitaet Bergakademie Freiberg Universitaetsbibliothek "Georgius Agricola", 2013. http://nbn-resolving.de/urn:nbn:de:bsz:105-qucosa-104526.
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Im Rahmen dieser Arbeit wurden Siliciumkomplexe mit dianionischen Pyrrol-2-carbaldimin-funktionalisierten N,N,O- und N,N,N,N-Chelatliganden synthetisiert und kristallografisch, NMR- und UV/Vis-spektroskopisch und mittels quantenchemischer Berechnungen charakterisiert. Die pentakoordinierten Si-Komplexe mit N,N,O-Ligandrückgraten wiesen in Abhängigkeit von den weiteren Si-gebundenen Substituenten unterschiedlich konfigurierte verzerrt trigonal-bipyramidale Si-Koordinationssphären auf. Die Ursache der Farbigkeit dieser Verbindungen konnte mittels quantenchemischer Berechnungen detailliert erklärt werden. – Die Si-Komplexe mit N,N,N,N-Ligandrückgraten liegen in Abhängigkeit von den weiteren Si-gebundenen Substituenten als 5-fach koordinierte kationische oder neutrale 6-fach koordinierte Si-Komplexe vor. Deren Farbigkeit wurde mittels UV/VIS-Spektroskopie untersucht. Von ausgewählten Komplexen wurden die Tensoren der 29Si-NMR-Verschiebung rechnerisch und CP/MAS-NMR-spektroskopisch bestimmt.
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Garrett, Andrew D. Templeton J. L. "Transformations of nitrile, amido, and imine ligands in Tp[prime] tungsten complexes." Chapel Hill, N.C. : University of North Carolina at Chapel Hill, 2007. http://dc.lib.unc.edu/u?/etd,810.
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Thesis (Ph. D.)--University of North Carolina at Chapel Hill, 2007.Title from electronic title page (viewed Dec. 18, 2007). "... in partial fulfillment of the requirements for the degree of Doctor of Philosophy in the Department of Chemistry." Discipline: Chemistry; Department/School: Chemistry. On t.p., [prime] is the symbol.
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Pandrapragada, Ravi Kumar. "Synthesis and characterization of novel phosphinimine ligand systems for potential applications in radiopharmaceuticals." Diss., Columbia, Mo. : University of Missouri-Columbia, 2007. http://hdl.handle.net/10355/5100.
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Thesis (M.S.)--University of Missouri-Columbia, 2007.The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file (viewed Nov. 1, 2007). Vita. Includes bibliographical references.
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Mugo, Jane Ngima. "Metal complexes based on monomeric and dendrimeric pyrrole-imine ligands as catalytic precursors." Thesis, University of the Western Cape, 2007. http://etd.uwc.ac.za/index.php?module=etd&action=viewtitle&id=gen8Srv25Nme4_7455_1242709415.
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Over the recent past, organometallic chemistry has grown and the impact of catalytic applications in various chemical technologies has rapidly evolved from the realm of academic laboratories into full-scale industrial processes. Pyrrole-imine ligands were prepared by condensation of pyrrole-2-carboxylaldehyde with propyl amine, 2,6-diisopropylanaline, poly(propylene) imine dendrimer and 3-aminopropyl-triethoxysilane to give the desired ligands in good yields. These ligands were charaterized via combination of techniques to establish the molecular structure. Microanalysis was performed to confirm the purity of the product.
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Bonnet, Ludovic GreÌgoire. "New chiral N-heterocyclic carbene-imine ligands and their application to asymmetric catalysis." Thesis, University of Birmingham, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.403052.
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Profirio, Daniel de Moraes 1989. "Atividades antibacteriana e citotóxica de um complexo de Au(III) contendo ligante pirrolil-imina." [s.n.], 2014. http://repositorio.unicamp.br/jspui/handle/REPOSIP/248530.
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Orientador: André Luiz Barboza FormigaDissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Química
Made available in DSpace on 2018-08-25T06:44:24Z (GMT). No. of bitstreams: 1 Profirio_DanieldeMoraes_M.pdf: 7198649 bytes, checksum: 018efc71d59b6427976118e0cc5f772a (MD5) Previous issue date: 2014
Resumo: Neste trabalho realizou-se a síntese de três ligantes contendo a unidade pirrolil-imina e de um complexo de Au(III). Os ligantes foram sintetizados partindo-se do pirrol-2-carboxaldeído e etilenodiamina ou orto-fenilenodiamina, obtendo-se assim o N,N'-bis(pirrol-2-il-metileno) etano-1,2-diamina (pyren), o N,N'-bis(pirrol-2-il-metileno)benzeno-1,2-diamina (bis-pyrophen), o N-(pirrol-2-il-metileno)benzeno-1,2-diamina (monopyrophen) e o complexo [Au(pyren)]PF6 como produtos. Os compostos foram caracterizados por análise elementar, MS, espectroscopia no IV e UV-Visível, RMN de H, C e HMBC H-N, cálculos teóricos por DFT e TD-DFT. Foram realizados também ensaios antibacterianos e citotóxicos com o complexo [Au(pyren)] e com o ligante pyren, sendo que o complexo apresentou maior atividade em ambos os ensaios comparado ao ligante. Com isso um mecanismo de ação via interação com o DNA foi investigado por estudos de fluorescência, ensaios de competição com brometo de etídio e espectroscopia de dicroísmo circular, revelando que o DNA é um possível alvo biológico do complexo
Abstract: In this work the syntheses of three ligands containing the pyrrolyl-imine unit and a Au(III) complex were performed. The ligands were synthesized starting from pyrrole-2-carboxaldehyde and ethylenediamine or ortho-phenylenediamine, to obtain N,N¿-bis (pyrrol-2-yl-methylene)ethane- 1,2-diamine (pyren), N,N¿-bis(pyrrol-2-yl-methylene)benzene-1,2-diamine (bis-pyrophen), N-(pyrrol-2-yl-methylene)benzene-1,2-diamine (mono-pyrophen) and the complex [Au(pyren)]PF6 as products. The compounds were characterized by elemental analysis, MS, IR, UV-Visible, H, C and (H-N) HMBC NMR spectroscopies and theoretical calculations by DFT and TD-DFT. Cytotoxic and antibacterial assays with [Au(pyren)] and the free ligand pyren were performed, and the complex showed a higher activity in both cases in comparison to the ligand. A mechanism of action via interaction with DNA was investigated by fluorescence techniques, competition studies with ethidium bromide and circular dichroism spectroscopy, showing that DNA is a potential biological target for the complex
Mestrado
Quimica Inorganica
Mestre em Química
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Blackmore, Ian John. "The reactivity of the bis(imino)pyridine ligand towards alkylating agents and the role of acid in ligand exchange reactions." Thesis, Imperial College London, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.412026.
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Mukiza, Janvier. "Rhenium complexes with pontentially multidentate ligands containing the amino, imino, hydroxy and thiol groups." Thesis, Nelson Mandela Metropolitan University, 2016. http://hdl.handle.net/10948/12308.
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The chemistry of rhenium has received considerable interest due to its versatility in various catalytic applications, fixation and especially the potential use of 186Re and 188Re radionuclides in nuclear medicine. This study investigates the synthesis and characterisation of rhenium complexes with potentially multidentate ligands containing the amino, imino, hydroxyl and thiol groups. It reports new rhenium complexes in the +1, +3, +4 and +5 oxidation states, which display structural diversity, from monomers to ligand-bridged dimers as well as metal-metal multiply bonded dimers. The reaction of orotic acid (H2oa) and 2-mercapto-orotic acid (H2moa) with trans- [ReOX3(PPh3)2] (X = Cl, Br) were studied and led to the formation of ligand-bridged dimers with metal-metal multiple bonds i.e. (μ-Br)(μ-O)(μ-oa)[Re2 IVBr(OEt)2(PPh3)2], (μ-X)(μ-O)(μ-oa)[Re2 IVX2(OiPr)(PPh3)2] and (μ-Cl)(μ-O)(μ-moa)2[Re(PPh3)]2. The reaction of H2oa with [ReO2(py)4]Cl, [Re(dab)Br3(PPh3)2] (H2dab = 1,2- diaminobenzene) and [Re(CO)5Cl] were also studied and monomeric complexes [ReO(py)2(OEt)(oa)], [Re(dab)Br(oa)(PPh3)2] and (Ph4P)[Re(CO)3(H2O)(oa)] were isolated. The treatment of 5-amino-orotic acid (H2aoa) with [ReOBr3(PPh3)2] led to dimers with metal-metal triple bonds ReIV≡ReIV i.e. (μ-Br)(μ-O)(μ-oa)[Re2 IVBr(OEt)2(PPh3)2], (μ-Br)(μ-O)(μ-oa)[Re2 IVBr2(OiPr)(PPh3)2], as well as the monomer [ReV(apd)Br(aoa)(PPh3)2] (apd2− = 5-imidopyrimidine-2,4-dione). The chelating ligand 5-aminopyrimidine-2,4-dione (H2apd) was formed by oxorhenium(V)-catalysed decarboxylation of 5-amino-orotic acid (H2aoa) (see Scheme 1). The reaction of the Schiff base derivative of 5-amino-ortic acid, salicylimine-orotic acid (H2soa), with trans-[ReOI2(OEt)(PPh3)2] in ethanol was also investigated and led to the formation of the rhenium(III) complex salt [Re(coa)I(PPh3)2]I [Hcoa = 5-(2- hydroxybenzylideneamino)pyrimidine-2,4(1H,3H)-dione]. The chelating Hcoa is also formed from the oxorhenium(V)-catalysed decarboxylation of H2soa and coordinates to the rhenium(III) ion as a monoanionic tridentate N,O,O-donor chelate via the phenolate and ketonic oxygens, and the imino nitrogen atom. However, decarboxylation of H2soa was not observed in its reaction with [ReOCl3(PPh3)2], which led to the isolation of [ReOCl(soa)(PPh3)]. The reaction of the carboxamide derivative of 5-aminoorotic acid, 5-(5-aminopyrimidine-2,4(1H,3H)- dioxamido)-1,2,3,6-tetrahedro-2,6-dioxopyrimidine-4-carboxylic acid (H2ampa) with [Re(CO)5Cl] in ethanol led to the formation of a zwitterionic rhenium(I) complex [Re(CO)3(H2O)(amef)] [amef = {5-(5-ammoniumpyrimidine-2,4(1H,3H)-dioxamido)- 1,2,3,6-tetrahedro-2,6-dioxopyrimidine-4-ethylformate}]. The chelating ion amef was formed from the combined tricarbonylrhenium(I)-catalysed esterification and aminoprotonation of H2ampa (see Scheme 1) and coordinates to the fac-[Re(CO)3]+ core as a dianionic bidentate N,N-donor chelate via the amido nitrgens.
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Kennedy, Margaret D. "Synthesis of and computational studies on C(s)- and C(1)-symmetric bis(imino) pyridine ligands." Click here for download, 2009. http://proquest.umi.com.ps2.villanova.edu/pqdweb?did=1786804491&sid=1&Fmt=2&clientId=3260&RQT=309&VName=PQD.
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Volbeda, Jeroen [Verfasser]. "The coordination chemistry of edge-bridged open indenyl and imidazolin-2-imine ligands / Jeroen Volbeda." München : Verlag Dr. Hut, 2014. http://d-nb.info/1058284908/34.
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Oliveira, Fabrícia Alvisi de. "Participação do CD40L solúvel e da metaloproteinase de matriz -9 na resposta imune na leishmaniose visceral humana." Universidade Federal de Sergipe, 2016. https://ri.ufs.br/handle/riufs/3621.
Full textAbstract:
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPESIn the present study, the sera levels of soluble CD40 ligand (sCD40L) and matrix metalloproteinase-9 (MMP-9) were quantified by Luminex assay in Visceral leishmaniasis patients before and during treatment follow-up and after regular antimony treatment and also in individuals exposed to infection, living in endemic areas. Different from the other molecules present in sera from classic VL patients, sCD40L and MMP-9 are fairly increased, and increase over time during the follow-up of VL patients undergoing antimony treatment. sCD40L and MMP-9 sera levels were also high in individuals living in endemic settings at high risk of infection (endemic controls). On the other hand, sCD40L and MMP-9 were not observed in sera from non-endemic controls, which are not exposed of infection. Additionally, negative correlations were found between spleen sizes and MMP-9 before treatment and sCD40L at day 15 of treatment. Negative correlations were also found between parasite load with both sCD40L and MMP-9. These findings indicate that both molecules can be used in monitoring therapeutic efficacy in VL. Furthermore, these data suggest a protective effect of these molecules, since the individuals exposed to infection without the symptoms of disease have high sera levels of sCD40L and MMP-9. These data were published in BMC Infectious diseases journal [1]. To confirm the protective effect of sCD40L present in sera of VL patients and determine if this molecule had biological activity, the ability of sera from patients containing high levels of this molecule sCD40L to control infection in vitro in Leishmania infantum infected macrophages, and the ability to induce cytokines production. Thereby, macrophages from of healthy donor were infected with Leishmnia infantum, and later incubated in presence of sera from individuals exposed to infection in presence of anti-CD40L. The infection was evaluated by counting of the number of infected macrophages/100 and the number of intracellular amastigotes/100 macrophages. The data showed that serum sCD40L decrease the number of infected macrophages and the number of intracellular amastigotes. The blockage of sCD40L activity with specific antibody, increase the infection. Moreover, the analysis of cytokines in supernatant of these macrophage cultures by Luminex assay demonstrated that sCD40L induces the IL-12, IL-23, IL-27, IL-15 e IL-1 production. The levels of these cytokines is inversely correlated with infection rate and the number of intracellular parasites from infected macrophages. A second manuscript with these data were published in PLOS One [2] . These results demonstrated that serum sCD40L from individuals exposed to VL improve the microbicide effect and the inflammatory cytokine production, suggesting its potential use in VL immunotherapy. Nevertheless, there is still a long way to be approached in future experimental and clinical studies.
No presente estudo, os níveis séricos dos marcadores inflamatórios CD40 ligante solúvel (sCD40L) e da metaloproteinase de matrix-9 (MMP-9) foram quantificados por Luminex nos pacientes com leishmaniose visceral antes, durante e após o tratamento com antimonial, e em indivíduos controles expostos à infecção, residindo em áreas endêmicas. Ao contrário das outras moléculas inflamatórias presentes nos soros de pacientes com LV, as moléculas sCD40L e MMP-9 apresentaram elevação moderada, havendo um aumento significativo de ambas no decorrer do tratamento com antimonial. Níveis séricos elevados de sCD40L e MMP-9 também foram encontrados nos indivíduos controles sem doença, provenientes de áreas endêmicas e expostos a infecção. Entretanto, o sCD40L e a MMP-9 não foram detectados nos soros de indivíduos de áreas não endêmicas, os quais não estão expostos a infecção. Adicionalmente, correlações negativas entre o tamanho do baço com a MMP-9 antes do tratamento e com o sCD40L 15 dias após o início do tratamento foram observadas, bem como correlações negativas entre ambas as moléculas com a carga parasitaria dos pacientes. Estes resultados indicam que estas moléculas podem ser utilizadas no monitoramento da eficácia terapêutica na leishmaniose visceral. Além disso, estes dados nos sugerem um efeito protetor dessas moléculas contra a doença, desde que os indivíduos expostos e sem a doença apresentaram concentrações elevadas dessas moléculas. Estes dados foram publicados no BMC Infectious diseases [1]. Para confirmar o efeito protetor do sCD40L e investigar se a molécula presente nos soros dos pacientes com LV tinha atividade biológica, foi avaliado se o sCD40L presente no soro dos indivíduos infectados teria ação na resposta leishmanicida e na produção de citocinas por macrófagos infectados por Leishmania infantum. Dessa forma, macrófagos de doadores normais foram infectados com L. infantum e posteriormente incubados com soro de indivíduos expostos a infecção na presença de anti-CD40L. A avaliação da infecção através da contagem de células infectadas e do número de parasitas intracelulares demonstrou que a presença do sCD40L sérico diminui o número de macrófagos infectados e o número de amastigotas intracelulares. O bloqueio da atividade do sCD40L com anticorpo específico reverteu este efeito, aumentando a infecção. Além disso, a análise de citocinas no sobrenadante das culturas de macrófagos por Luminex mostrou que a adição de sCD40L induziu a produção de IL-12, IL- 23, IL-27, IL-15 e IL-1. As concentrações destas citocinas correlacionaram-se inversamente com as taxas de infecção e com o número de parasitas intracelulares nos macrófagos infectados. Um segundo artigo com estes resultados foi publicado na PLOS One [2]. Estes resultados demonstram que o sCD40L sérico dos indivíduos expostos à LV melhora a capacidade microbicida e a produção de citocinas inflamatórias, sugerindo seu potencial uso na imunoterapia na LV humana, embora este seja um longo caminho a ser abordado em estudos futuros experimentais e clínicos.
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El, Hajjaji Samir. "Asymmetric transition metal-catalyzed alkyl addition to imines with chiral phosphine ligands." Thesis, University of Nottingham, 2010. http://eprints.nottingham.ac.uk/11185/.
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The research project presented in this thesis deals with the development of the alkylation of protected aldimines using organoaluminium and organozinc compounds as alkylating agents. To this end, efforts have been focused into the methylation reaction using trimethylaluminium and dimethylzinc. It was hoped to establish promising conditions using the methylate group and then to extend the catalytic system to other interesting nucleophiles. In the case of organoaluminium alkylation the reaction was extended to other nucleophiles, namely to the allyl and propargyl groups. The identificaton of suitable metal catalysts as well as diphosphine ligands was carried out by means of extensive high throughput screening. On the one hand [IrCl(COD)]2 proved to be very efficient when associated to AlMe3 or DABAL-Me3 in the non-enantioselective 1,2-addition reactions to aldimines (100% conversion in 3 h). On the other hand, [RhCl(COD)]BF4 was found to be able to efficiently catalyse the enantioselective 1,2-addition of Me2Zn to aldimine substrates (100% conversion in 3 h - up to 99% e.e.). A preliminary screening of a range of aldimines bearing different protecting groups aimed at selecting the most interesting substrate in terms of reactivity and ease of cleavage of the protecting group. Once this substrate had been identified, a range of derivatives was synthesised in order to appraise the scope of the newly developed reaction. The diphenylphosphinoyl (dpp) protecting group turned out to be the best activating group for aldimines tested within the framework of this study. In addition to being easy to introduce, the dpp group can also be removed easily under mild conditions. What is more, the presence of a phosphorus atom on this protecting group is a feature which was used to determine the enantiomeric excess by 31P NMR spectroscopy, thus providing a novel and efficient screening tool at disposal. In the course of this investigation, various issues were faced and tackled. One of them was the unexpected non-reproducibility taking place in the Rh-catalysed Me2Zn addition reaction; however, a deeper thinking of the reaction mechanism enabled us to solve this problem to eventually get a more robust catalytic system. Another one was the formation of a reduction product as a by-product of the Rh-catalysed Me2Zn addition reaction. Finally, several interesting attempts (Et2Zn addition, aliphatic imine synthesis), findings (effect of ligand bite angle) and hypotheses (testing of the BPM ligand) made during this study deserve to be studied further for improvement and optimisation.
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Alhalafi, Mona Hanash A. "Pyridone-substituted pyridyl imines as functionalised ligands in coordination chemistry and catalysis." Thesis, University of Leicester, 2018. http://hdl.handle.net/2381/42404.
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In this thesis, the synthesis and coordination chemistry of a series of novel NNN and NN proton responsive ligands are described. All the ligands and complexes have been characterized by a combination of multinuclear NMR spectroscopic techniques, mass spectrometry, IR spectroscopy and by single crystal X-ray diffraction studies. Chapter 1 presents an introduction to functional ligands/complexes and their applications in catalysis. In Chapter 2, the synthesis and characterisation of a series of OH-functionalised NNN pincer ligands are discussed. The coordination chemistry of these pyridone-substituted pyridyl-imines towards platinum group metals is thoroughly investigated. It is envisaged that these ligands can remain protonated or undergo deprotonation reactions on coordination to give complexes of the type L1PdX (X = Cl, OAc), [HL1PdCl][X] (X = Cl, PF6, OTf), HL1RuCl2(PPh3) and [HL1PtCl][PtCl3(DMSO)]. Additionally, the reactivity of the palladium chloride complexes towards stoichiometric amounts of AgPF6 is explored with a view to introducing two electron donor ligands (L) to the coordination sphere of the metal centre, including acetonitrile and 3,5-lutidine. In Chapter 3, the synthesis and reactions of two classes of OH-functionalised NN-bidentate ligands towards group 10 metal salts of Pd(II), Pt(II) and Ni(II) including Pd(OAc)2, (MeCN)2PdCl2 (DMSO)2PtCl2 and (DME)NiBr2 are described. A thorough investigation is performed to ascertain the preferred coordination mode and charge on the heterocyclic unit of the NN-ligand. In addition, the reactivity of a selection of the palladium complexes towards some two electron donor ligands (L), including acetonitrile and triphenylphosphine is also studied. Furthermore, the reactions of a selection of the resulting compounds towards acids and bases is investigated to explore their proton responsiveness. In Chapter 4, the NNN-Ru and -Pd complexes developed in Chapter 2 have been used as catalysts in transfer hydrogenation. Additionally, the NN-nickel complexes described in Chapter 3 have been investigated as pre-catalysts in ethylene oligo-/polymerisation. In both these types of catalysis the effect of the pendant OH group on the particular transformation is probed. Chapter 5 details the experimental work carried out in Chapters 2-4.
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Motoboli, Mpho Princess. "Synthesis and modelling of imine derivatives as ligands for Grubbs type pre–catalysts / by Mpho Princess Motoboli." Thesis, North-West University, 2010. http://hdl.handle.net/10394/4633.
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The Grubbs type pre–catalysts are widely used for olefin metathesis. The pre–catalysts
exhibit high activity and selectivity, but low stability and short lifetimes
Salicylideneanilines (SA) are Schiff bases that can be derived from the reaction of
amine derivatives with salicylaldehyde and 2–hydroxy–1–naphthaldehyde. These
ligands were synthesized to improve the activity, stability and lifetime of the Grubbs
first and second generation pre–catalysts. In an attempt to improve on these properties
both theoretical and experimental investigations were conducted.
Molecular modelling was done using Material Studio, Dmol3 (PW91/GGA/DNP) to
evaluate potential imine derivative as ligands for Grubbs type pre–catalysts, for the
metathesis reaction with 1–octene. Forty five ligands were chosen to investigate
properties for suitable ligands. The usefulness of the HOMO energy as preliminary
criteria for screening suitable ligands was investigated. The HOMO energy of
possible ligands was calculated against the well defined Verpoort ligand. In this study
the ligand with lower energy than that of the Verpoort's ligand was considered.
Analysis of the electron density, electrostatic potential, Fukui functions, HOMOLUMO
orbitals and population analysis were used to address the research problem.
The second criteria included being found in literature, synthesis procedure as well as a
high yield. The two most promising ligands were chosen to be synthesized. These
ligands were used in the synthesis of new Grubbs 1 and 2 type pre–catalysts. The third
criteria were the dissociation energy (Ru–N) for the new Grubbs type pre–catalysts for
activation properties that may influence the hemilability. Furthermore molecular
modelling helped to gain insight into the mechanism of the 1–octene metathesis
reaction by using the Potential Energy Surface (PES) scan.
Both ligands were successfully synthesized according to literature methods. The
ligands were characterized by MS, IR and NMR techniques. The synthesis of
substituted Grubbs 1 type pre–catalysts was unsuccessful. The substituted Grubbs 2
type pre–catalysts were obtained and characterized by MALDI–TOF and NMR
techniques. The two substituted Grubbs 2 type pre–catalysts were tested for metathesis
activity with 1–octene. Only one substituted pre–catalyst was active for metathesis.
This catalyst was less active and selective than the Grubbs first and second generation
pre–catalysts but showed an increased lifetime.Thesis (M.Sc. (Chemistry))--North-West University, Potchefstroom Campus, 2011.
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Salazar, Garza Gustavo Adolfo. "Microwave-Assisted Synthesis and Photophysical Properties of Poly-Imine Ambipolar Ligands and Their Rhenium(I) Carbonyl Complexes." Thesis, University of North Texas, 2017. https://digital.library.unt.edu/ark:/67531/metadc1011818/.
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The phenomenon luminescence rigidochromism has been reported since the 1970s in tricarbonyldiimine complexes with a general formula [R(CO)3LX] using conventional unipolar diimine ligands such as 2,2;-bipyridine or 1,10-phenanthroline as L, and halogens or simple solvents as X. As a major part of this dissertation, microwave-assisted synthesis, purification, characterization and detailed photoluminescence studies of the complex fac-[ReCl(CO)3L], 1, where L = 4-[4,6-bis(3,5-dimethyl-1H-pyrazol-1-yl]-N,N-diethylbenzenamine are reported. The employment of microwaves in the preparation of 1 decreased the reaction time from 48 to 2 hours compared to the conventional reflux method. Stoichiometry variations allows for selective preparation of either a mononuclear, 1, or binuclear, fac-[Re2Cl2(CO)6], 2, complex. The photophysical properties of 1 were analyzed finding that it possesses significant luminescence rigidochromism. The steady state photoluminescence emission spectra of 1 in solution shift from 550 nm in frozen media to 610 nm when the matrix becomes fluid. Moreover, a very sensitive emission spectral analysis of 0.1 K temperatures steps shows a smooth transition through the glass transition temperature of the solvent host. Furthermore, synthetic modifications to L have attained a family of ambipolar compounds that have tunable photophysical, thermophysical and other material properties that render them promising candidates for potential applications in organic electronics and/or sensors - either as is or for their future complexes with various transition metals and lanthanides.
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He, Fan. "Transition metal complexes with N-heterocyclic carbene ligands : synthesis and reactivity." Thesis, Strasbourg, 2015. http://www.theses.fr/2015STRAF031/document.
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L’objectif de ce travail est la synthèse de complexes contenant des ligands NHC protiques fonctionnalisés avec un groupement imine dans le but de développer des méthodologies de synthèse donnant accès à des ligands pNHC ainsi que la synthèse des groupes imidazolide anioniques liés par le C et leurs complexes homo et hétéro-dinucléaires. Dans le cas des imidazoles sans groupe fonctionnel, la déprotonation à l’aide de n-butyl lithium a permis l’obtention de (1-aryl-1H-imidazol-2-yl)lithium avec de bons rendements. La réaction de (1-aryl-1H-imidazol-2-yl)lithium avec [Ir(cod)(μ-Cl)]2 ou [Rh(cod)(μ-Cl)]2 a conduit à des complexes dinucléaires bipontés en C2,N3. Dans le cas de l’imidazole possédant une fonctionnalité imine, le complexe de l’Ir(I) lié au N de l’imidazole peut se tautomériser en complexe de l’Ir(I) imine avec un ligand pNHC suite à la réaction d’abstraction du chlorure à température ambiante, alors que la tautomérisation de l’analogue du Rh(I) nécessite une température de 110°C. La déprotonation des complexes de l’Ir(I) et Rh(I) liés par le N de l’imidazole avec addition de [Ir(cod)(μ-Cl)]2 ou de [Rh(cod)(μ-Cl)]2 in situ permet l’obtention de complexes homo et hétéro-dinucléaires. La métallation des sels d’imidazolium fonctionnalisés avec un groupement imine s’est avére être une méthode efficace pour la synthèse de complexes métallés ayant un ligand pNHC et a été étendue des complexes bidentes aux complexes chélatants pNHCThe purpose of this work is the synthesis of complexes containing imine-functionalized protic NHC ligands in order to further develop synthetic methodologies giving access to pNHC, C-bound ‘anionic’ imidazolide, and homo- and heterodinuclear complexes. In the case of imidazoles without functional group, deprotonation with n-butyl lithium afforded (1-aryl-1H-imidazol-2-yl)lithium in good yield. Reaction of (1-aryl-1H-imidazol-2-yl)lithium with [Ir(cod)(μ-Cl)]2 or [Rh(cod)(μ-Cl)]2 yielded a doubly C2,N3-bridged dinuclear complex. In the case of imine-functionalized imidazole, the Ir(I) N-bound imidazole complex can tautomerize to Ir(I) imine-functionalized pNHC complex chloride abstraction at room temperature, while in the Rh(I) analog the tautomerization can be achieved at 110 °C. In situ deprotonation of the N-bound imidazole Ir(I) or Rh(I) complexes, followed by addition of [Ir(cod)(μ-Cl)]2 or [Rh(cod)(μ-Cl)]2 led to the isolation of homo- and heterodinuclear complexes. The metalation of imine-functionalized imidazolium salts is also an effective procedure for synthesis of pNHC metal complexes, and it was extended from bidentate to pincer-type pNHC complexes
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Le, Fur Nicolas. "Synthèse et métallation des sulfoxydes benzodiaziniques. Synthèse asymétrique de sulfoxydes aromatiques, métallation et applications." Rouen, 2004. http://www.theses.fr/2004ROUES046.
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Dans une première partie, la synthèse de 15 nouveaux sulfoxydes benzodiaziniques a été décrite. La métallation de ces molécules suivie de l'addition de divers électrophiles a permis de confirmer le bon pouvoir ortho-directeur du groupe sulfoxude mais aussi son caractère nucléofuge lorsqu'il se situe sur la partie diazinique de la molécule. Lors de l'addition d'électrophiles prochiraux (aldéhydes, imines), le groupe sulfoxyde a montré une diastéréosélectivité modeste à totale selon l'encombrement de l'électrophile. La décomposition thermique du groupe tert-butylsulfinyle en acide sulfénique a été observée et mise à profit pour la préparation de structures polycycliques de type benzisothiazoline. Dans une seconde partie, la synthèse asymétrique de sulfoxydes aromatiques tert-butylés a été réalisée. Ces molécules énanttiopures ont été préparées par l'addition de lithiens aromatiques (benzène, naphtalène, pyridine, quinoléine et pyridazine) sur le tert-butanethiosulfinate de tert-butyle. Une étude de la métallation de ces molécules a permis de montrer une totale induction asymétrique du groupe tert-butylsulfinyle lors de l'addition d'imines N-tosylées prochirales en tant qu'électrophiles. Des applications de ces nouveaux amino-sulfoxydes chiraux ainsi obtenus ont été explorées que ce soit comme précurseurs d'amines optiquement actives ou comme nouveaux ligands chiraux de type N-S pour la catalyse asymétrique. Par ailleurs, la cyclisation thermique de ces molécules a conduit à la formation d'analogues chiraux de type benzisothiazolineThe syntheses of 15 new sulfinylbenzodiazines have been described. Their metalation was studied and confirmed the good ortho directing power as well as the leaving group abilities of the sulfoxide groups. The use of prochiral electrophiles (aldehydes, imines) has highlighted modest to high diastereoselectivities during the addition step depending on the steric hindrance of the electrophile. Thermal decomposition of the tert-butanesulfinyl group to sulfenic acid has been observed leading to cinnolinic benzisothiazoline-like structures. In a second part, several enantiopure aromatic tert-butanesulfoxides have been synthesised. They were prepared by the substitution of tert-butanethiosulfinate by an aryllithium (benzene, naphthalène, pyridine, quinoline et pyridazine). The subsequent metalation of these molecules was studied and a complete asymmetric induction of the tert-butanesulfinyl group was found when prochiral imines were used. Application of these new chiral amino-sulfoxides as enantiopure amine precursors or as new N-S type ligands for asymmetric catalysis have been explored. Finally, thermal cyclisation of these amino-sulfoxides led to chiral analogs of benzisothiazoline structures
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De, Jongh Leigh-Anne. "Imine-donor complexes with group 6 and group 11 transition metals : coordination and dynamics." Thesis, Stellenbosch : Stellenbosch University, 2008. http://hdl.handle.net/10019.1/2001.
Full textAbstract:
Thesis (MSc (Chemistry and Polymer Science))--Stellenbosch University, 2008.In this study the coordination of ligands with several coordination sites, 2-aminoazoles (2- amino-4-methylthiazole), 2-aminobenzothiazole, 2-aminobenzoimidazole and 2- aminothiazoline and a biguanidine (N-(2-methylphenyl)imidodicarbonimidic diamide) to soft metal centres [gold(I) (group 11), chromium(0) (group 6) and tungsten (0) (group 6)] was investigated. The aminoazoles have three coordination sites, an exocyclic amine nitrogen, an endocyclic imine nitrogen and an endocyclic thioether sulphur. The biguanidine ligand has three sites for deprotonation, one central amine and two imine nitrogens, and at least five sites available for nitrogen coordination.
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Perman, Jason Alexander. "Solid-State Synthesis of Imide Ligands for the Self-Assembly of Metal-Organic Materials." Scholar Commons, 2011. http://scholarcommons.usf.edu/etd/3747.
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In this research project, reduction or complete elimination of organic solvents is explored in the synthesis of cyclic imides using a technique that brings reagents into favorable position to react. Cocrystal Controlled Solid-State Synthesis (C3Sy3), takes advantage of supramolecular interactions such as hydrogen bonding and π-π stacking to form a cocrystal which can sequential be heated to complete the condensation reaction and produce a desirable product. Twenty-five successful condensation reactions result in high and clean yield.
C3Sy3 of cyclic imides with auxiliary hydrogen bonding moieties like carboxylic acid, carboxylate or pyridyl groups are amenable to form additional solid-state materials. These moieties are useful in forming coordinate covalent bonds with metal cations. Using these C3Sy3 synthesized molecules as ligands, various Metal-Organic Materials (MOMs) are self-assembled. These MOMs offer unique qualities owing to the properties of the cyclic imides. With the addition of accessible carbonyl groups, they may participate as hydrogen bond acceptors or hydrophilic groups. Various degrees of rotation of N-phenyl substituents around the imide plane allow for structural flexibility as a route to supramolecular isomers in MOMs. The ease in imide synthesis may allow the fast scale-up of these ligands for industrial application. Similar ligands are generally synthesized by cross-coupling or substitution reactions that require expensive catalyst and various organic solvents.
Metal-organic materials are a class of compounds amenable to crystal engineering owing to the directional coordinate covalent bonds between metal or metal clusters and organic ligands. They are characterized by X-ray diffraction, spectroscopy, volumetric and gravimetric analysis. The C3Sy3 imides were used to construct various MOMs, from discrete nanostructures to extended 3-periodic frameworks that possess viable internal space for applications pertaining to porous materials. Structural characterization by single crystal X-ray diffraction and structure-function relations are addressed. Gas sorption experiments show that many of these materials are structurally robust and retain crystallinity after evacuation. Ion exchange and guest uptake experiments using the synthesized materials demonstrate their potential as agents for sequestration.
The bottom-up synthesis of metal-organics materials is leading the field of crystal engineering with built-in properties, showing promise by combining attributes from both inorganic and organic components.
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Aal, Frouke [Verfasser]. "Synthese und Koordinationschemie mehrzähniger Imidazolin-2-imin-Liganden / Frouke Aal." München : Verlag Dr. Hut, 2013. http://d-nb.info/1042878528/34.
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Wu, Xianghong Gorden Anne Elizabeth. "Synthesis and applications of 2-quinoxalinol salens and their metal complexes." Auburn, Ala., 2008. http://hdl.handle.net/10415/1425.
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Winston, Scott. "Functionlised N-heterocyclic carbenes and amido imino mixed donors as supporting ligands in organometallic catalysis." Thesis, University of Southampton, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.274654.
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Reich, Blair Jesse Ellyn. "Cyanide-catalyzed C-C bond formation: synthesis of novel compounds, materials and ligands for homogeneous catalysis." Texas A&M University, 2005. http://hdl.handle.net/1969.1/4987.
Full textAbstract:
Cyanide-catalyzed aldimine coupling was employed to synthesize compounds
with 1,2-ene-diamine and ñ-imine-amine structural motifs: 1,2,N,N'-
tetraphenyletheylene-1,2-diamine (13) and (+/-)-2,3-di-(2-hydroxyphenyl)-1,2-
dihydroquinoxaline (17), respectively. Single crystal X-ray diffraction provided solidstate
structures and density functional theory calculations were used to probe isomeric
preferences within this and the related hydroxy-ketone/ene-diol system. The enediamine
and imine-amine core structures were calculated to be essentially identical in
energy. However, additional effects-such as ÃÂ conjugation-in 13 render an enediamine
structure that is slightly more stable than the imine-amine tautomer (14). In
contrast, the intramolecular hydrogen bonding present in 17 significantly favors the
imine-amine isomer over the ene-diamine tautomer (18).
Aldimine coupling (AIC) is the nitrogen analogue of the benzoin condensation
and has been applied to dialdimines, providing the first examples of cyclizations effected
by cyanide-catalyzed AIC. Sodium cyanide promoted the facile, intramolecular
cyclization of several dialdimines in N,N-dimethylformamide, methanol, or
dichloromethane/water (phase-transfer conditions) yielding a variety of six-membered
heterocycles. Under aerobic conditions, an oxidative cyclization occurs to provide the
diimine heterocycle.
Cyanide-catalyzed aldimine coupling was employed as a new synthetic method
for oligomerization. Nine rigidly spaced dialdimines were oxidatively coupled under
aerobic conditions to yield conjugated oligoketimines and polyketimines with
unprecedented structure and molecular weight (DP = 2 - 23, ~700 -8200 g/mol). The ñ- diimine linkage was established based on IR spectroscopy, NMR spectroscopy, size
exclusion chromatography, and X-ray crystallographic characterization of the model
oxidized dimer of N-benzylidene-(p-phenoxy)-aniline. Cyclic voltammetry indicates ptype
electrical conductivity, suggesting they are promising candidates for plastic
electronic devices.
The cyanide-catalyzed benzoin condensation reaction of 4-substituted
benzaldehydes followed by oxidation to the diketone, and the Schiff Base condensation
of two equivalents of o-aminophenol provides 2,3-(4-X-phenyl)2-1,4-(2-
hydroxyphenyl)2-1,4-diazabutadiene. The ligand is given the moniker X-dabphol.
These ligands are readily metallated to form M-X-dabphol complexes. The copper
complexes catalytically fix CO2 with propylene oxide to yield propylene carbonate. DFT
studies along with a comparison with Hammet parameters help validate and elaborate on
the catalytic cycle and the catalytic results obtained. The nickel complex is competent
for olefin epoxidation. Synthesis, characterization, X-ray structure, DFT analysis, and
catalytic activity of the parent nickel dabphol complex are reported.
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Fels, Sabine. "Höherkoordinierte Komplexverbindungen des Siliciums, Germaniums und Zinns mit chiralen O,N,O´-Liganden." Doctoral thesis, Technische Universitaet Bergakademie Freiberg Universitaetsbibliothek "Georgius Agricola", 2016. http://nbn-resolving.de/urn:nbn:de:bsz:105-qucosa-211546.
Full textAbstract:
Aufgrund ihrer Eigenschaften und möglicher Anwendungen werden Siliciumkomplexe mit O,N,O´-Ligandsystemen in der Literatur beschrieben. Jedoch fehlen bisher Untersuchungen zur Strukturaufklärung. Im Rahmen dieser Arbeit wurden zahlreiche Silicium-, Germanium- und Zinnkomplexe mit chiralen O,N,O´-Liganden synthetisiert und strukturanalytisch charakterisiert. Dazu wurden die Liganden durch Kondensationsreaktionen von enantiomerenreinen Aminosäuren mit aromatischen ortho-Hydroxyaldehyden bzw. Acetylaceton hergestellt. Die weitere Umsetzung der Liganden mit Elementhalogeniden der Gruppe 14 führte zu den angestrebten Komplexverbindungen. Alle hergestellten Verbindungen wurden umfassend charakterisiert (NMR-, UV/Vis-, IR-Spektroskopie, Elementaranalyse, Einkristallstrukturanalyse, Drehwert). Quantenchemische Berechnungen an einfachen Modellverbindungen sowie an hergestellten Silicium- und Zinnkomplexen führten zu einem grundlegenden Verständnis der Festkörper-NMR-Parameter dieser Verbindungsklasse.
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Kokel, Nicolas. "Réductions asymétriques de doubles liaisons catalysées par des complexes du rhodium coordinés par les ligands chiraux aminophosphinephosphinites." Lille 1, 1988. http://www.theses.fr/1988LIL10068.
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Bheeter, Linus Paulin. "catalyseurs à base de ligands carbène N-hétérocycliques dérivés de fer et de nickel pour les réactions catalytiques d'hydrosilylation et d'hydroboration." Thesis, Rennes 1, 2014. http://www.theses.fr/2014REN1S182.
Full textAbstract:
Ces travaux de thèse portent sur le développement de catalyseurs à base de ligands carbène N-hétérocycliques dérivés de fer et de nickel, deux métaux de transition abondants, pour les réactions de hydrosilylation et de borylation. Le premier chapitre porte sur les travaux réalisés à l’aide de complexes de fer du type [Cp(NHC)Fe(CO)₂][X] (X = I, PF₆) possédant des ligands de type benzimidazole ou imidazole et leur évaluation en hydrosilylation de dérivés carbonylés. Le deuxième chapitre traite de l’utilisation de complexes demi-sandwichs de nickel du type CpNi(NHC) en hydrosilylation d’aldéhydes, de cétones, d’aldimines et de cétimines. Enfin le troisième chapitre est consacré à la réaction de borylation catalysée par des complexes de nickel demi-sandwich CpNi(triazole)X et des complexes de nickel possédant deux ligands chélatants anioniques de type carbene N-hétérocyclique fonctionnalisé par un bras amidoThe research work described in this manuscript has for main objective the development of new homogeneous catalytic systems based on N-heterocyclic carbene (NHC) iron and nickel complexes for hydrosilyation and borylation reactions. The first chapter describes the use of [Cp(NHC)Fe(CO)₂][X] (X = I, PF₆) complexes bearing benzimidazole or imidazole NHC type ligands for hydrosilylation of benzaldehyde and acetophenone. In a second chapter, we have shown that half-sandwich NHC-nickel complexes in the presence of a catalytic amount of NaHBEt3 can be efficient catalysts for the reduction of aldehydes, ketones, aldimines and ketimines in the presence of diphenylsilane. In the last chapter, two new series of non-classical NHC-nickel triazole complexes had been developed: (i) one series with half sandwich NHC-nickel triazole complexes and (ii) another one based on chelating anionic amido-functionalized N-heterocyclic carbene nickel complexes. The two series of complexes were then evaluated in catalytic borylation cross coupling reaction
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Cao, Yu. "I. Synthesis Of Anthraquinone Derivatives For Electron Transfer Studies In DNA. II. Characterization Of The Interaction Between Heme And Proteins." Digital Archive @ GSU, 2011. http://digitalarchive.gsu.edu/chemistry_diss/55.
Full textAbstract:
Anthraquinone (AQ) derivatives with relatively high reduction potentials have been synthesized to afford good candidates for electron transfer studies in DNA. Electron withdrawing groups on the anthraquinone ring gave derivatives with less negative reduction potentials. The anthraquinone imide (AQI) derivatives had reduction potentials less negative than AQ derivatives. The AQI ring system was subject to base-induced hydrolysis.
Water-soluble sulfonated tetraarylporphyrins have been studied in a wide variety of contexts. Herein, we report the first synthesis of a pentasulfonated porphyrin bearing an internal cyclic sulfone ring. Treatment of 5,10,15,20-tetrakis(4-sulfonatophenyl)porphyrin (TPPS4) with fuming H2SO4 gave a structure consistent with initial sulfonation followed by dehydration to give a sulfone bridge between an ortho-position of one of the phenyl groups and a β-pyrrole position on the porphine ring (TPPS4Sc). The structure was established by ESI-MS and 1HNMR. The Soret absorption is red shifted by about 32 nm compared to that of TPPS4.
Streptococcus pyogenes obtains iron by taking up heme from the environment during infection. One of the heme uptake pathways is the Sia or Hts pathway. The initial protein in this pathway is Shr, which has two heme-binding NEAT domains, NEAT1 nearer the N-terminus, and NEAT2 nearer the C-terminus. We report biophysical characteristics of these two NEAT domains. To assess stability of this domain towards heme release, denaturation studies of the Fe(II) and Fe(III) forms were performed. For each domain, both the Fe(II) and the Fe(III) forms behave similarly in thermal denaturation and guanidinium denaturation. Overall, NEAT2 is more stable than NEAT1. Spectral signatures, sequence alignment and homology modeling for both domains suggest that one of the axial ligands is methionine. NEAT2 autoreduces as the pH increases and autooxidizes as the pH decreases. Heme uptake from the host environment is the only iron acquisition pathway in S. pyogenes; inhibition of this pathway might be an approach to infection control. Compounds that might inhibit the heme uptake pathway were selected via virtual screening.
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Trifonova, Anna. "Synthesis of Novel Chiral Bicyclic Ligands and their Application in Iridium-Catalyzed Reactions." Doctoral thesis, Uppsala : Acta Universitatis Upsaliensis, 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-5783.
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Gietz, Twyla Mae, and University of Lethbridge Faculty of Arts and Science. "Lithium complexes of ketoimines and novel alkynyl imines and diimines : discoveries in the attempted synthesis of PACNAC." Thesis, Lethbridge, Alta. : University of Lethbridge, Dept. of Chemistry and Biochemistry, c2010, 2010. http://hdl.handle.net/10133/2481.
Full textAbstract:
Two different methodologies were used to attempt the synthesis of a novel P‐N ligand,
denoted as PACNAC for the similarity to the analogous NACNAC and ACAC ligands.
Although the synthesis of PACNAC was not successful, each methodology led to interesting
discoveries. First, a number of lithium complexes of ketoimines were isolated and studied by Xray
crystallography and NMR spectroscopy revealing some interesting substituent based effects
on the structure, solubility and solution state behaviour. The X‐ray data of the two known and
two related novel ketoimines were also collected and compared to the lithium complexes.
Secondly, the synthesis of novel alkynyl imines along with the new alkynyl diimines by novel
synthetic routes and studied by x‐ray crystallography, NMR, electrochemistry, and UV‐Visible
spectra.xvi, 134 leaves : ill. (some col.) ; 29 cm + 1 CD-ROM
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Zanin, Maria Eduarda. "Pneumopatia experimental : expressão genica de Fas, Fas-ligante, Bcl-w e citocinas em pulmões de camundongos da linhagem /balb/c submetidos a exposição fungica (Lentinus edodes - Shitake e Aspergillus fumigatus)." [s.n.], 2002. http://repositorio.unicamp.br/jspui/handle/REPOSIP/311775.
Full textAbstract:
Orientador: Ricardo de Lima ZollnerDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Ciencias Medicas
Made available in DSpace on 2018-08-08T20:21:25Z (GMT). No. of bitstreams: 1 Zanin_MariaEduarda_M.pdf: 1416849 bytes, checksum: a8f43b38009831f8aa92831c13bdc49e (MD5) Previous issue date: 2002
Resumo: Atualmente, o interesse pelas reações provocadas pelo fungo Lentinus edodes, cogumelo Shiitake, tem aumentado acompanhando sua popularidade nos países do Ocidente, onde ele é cada vez mais empregado na culinária e como ¿elixir de boa saúde¿. Paralelamente, tem crescido o número de relatos de reações alérgicas provocadas pelo consumo e manuseio do cogumelo, principalmente em produtores, que entram em contato com os esporos, facilmente inalados, e desenvolvem reações como tosse, calafrios e febre após o contato. As respostas iniciadas após a exposição fúngica devem-se aos sistemas de modulação da resposta imune, tais como subtipos de célula T recrutados para a resposta (TH1 ou TH2), tipos de citocinas secretadas e apoptose. Nosso estudo foi direcionado para a observação dos mecanismos de resistência e susceptibilidade às reações pulmonares e sistêmicas (células esplênicas) contra o Shiitake, baseados na expressão gênica das citocinas IL-2, IL-4, IL-5, IL-12, TNF-a e IFN-g, e componentes apoptóticos Fas, Fas¿Ligante (Fas-L) e Bcl-w nos camundongos BALB/c submetidos à exposição de esporos de Shiitake e Aspergillus fumigatus, utilizado como parâmetro de comparação, uma vez que as reações por ele provocadas são amplamente descritas na literatura. Dessa forma, os resultados obtidos evidenciam a modulação direcionada para células TH1 provocadas pelos esporos de Shiitake e Aspergillus fumigatus nos animais estudados, com expressão aumentada das citocinas IL-12, TNF-a e IFN-g, tanto local quanto sistemicamente, além do aumento de linfócitos nos pulmões. O estudo dos componentes apoptóticos revelou a expressão da molécula Fas apenas nos pulmões e células esplênicas dos animais expostos aos esporos de Shiitake e Aspergillus fumigatus, com observação de apoptose in situ pelas técnicas de Feulgen e TUNEL realizadas nos pulmões desses animais, sugerindo a modulação desses fungos na ocorrência da apoptose
Abstract: The Lentinus edodes (Shiitake mushroom) is one the most popular edible mushrooms in the world. The indoor cultivation of Shiitake can lead to allergic symptoms in mushroom worker¿s, in contrast to outdoor cultivation where problems occur sporadically. Simultaneously have been growth relates of allergic reaction elicited by the consumption and handily of this mushroom, mainly between workers which inhaled the spores released during manipulation of Shiitake. These spores reaching the terminal area of the lung producing symptoms that suggest a delayed hypersensibility reaction with clinical symptoms of dispnea, cough, chills, and fever. The immune response after fungal exposition is attributed to the modulation of this response by the T cells subsets recruited (TH1 or TH2), cytokines release and apoptosis. The aim of this study was to verify the resistance and susceptibility to the Shiitake by the analyzes of molecular expression of cytokines IL-2, IL-4, Il-5, IL-12, TNF-a and IFN-g and apoptotic components Fas, Fas-L and Bcl-w, in lung and spleen cells of BALB/c submitted to Shiitake and Aspergillus fumigatus spores exposure, as a positive control of response. We found a over expression of cytokines IL-12, TNF-a, and IFN-g, in both compartments, systemic and locally (spleen cells and lung respectively), moreover, the lymphocytes were increased, suggesting the TH1 driving response evoked by exposure to Aspergillus fumigatus and Shiitake spores. The study of apoptotic components demonstrated the expression of Fas only in lungs and spleen cells of exposed animals to spores. The presence of apoptosis in lung was confirmed by the Feulgen and TUNEL techniques, suggesting the fungal modulation of apoptosis
Mestrado
Clinica Medica
Mestre em Clinica Medica
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Cheruku, Pradeep. "Asymmetric Hydrogenations : Syntheses of Ligands and Expansion of Substrate Scope." Doctoral thesis, Uppsala universitet, Institutionen för biokemi och organisk kemi, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-9353.
Full textAbstract:
Asymmetric hydrogenation has emerged as a versatile methodology to obtain a wide range of chiral precursors. This thesis focused on the synthesis of new chiral ligands and the expansion of the substrate scope of asymmetric hydrogenations. Paper I described the synthesis and evaluation of N,P-ligands for the Ir-catalyzed hydrogenations of unfunctionalized olefins. The substrate scope of Ir-catalyzed asymmetric hydrogenations is limited to a narrow range of “test” olefins. The foremost focus of this thesis was to expand the substrate scope of Ir-catalyzed asymmetric hydrogenations. Papers II and III disclosed the potential of the N,P-ligated Ir complexes in hydrogenation of the enol phosphinates. This substrate class is attractive because the hydrogenated products are chiral alkylphosphinates that can be transformed into chiral alcohols and chiral phosphines without sacrificing enantiopurity. A wide range of enol phosphinates were hydrogenated to excellent conversions and enatioselectivities. The hydrogenation of purely alkyl-substituted enol phosphinates in very high conversions and ee values was emphasized in these studies. Paper IV described the investigation of unfunctionalized enamines as substrates in Ir-catalyzed hydrogenation studies. The hydrogenation results and structural limitations of the substrates are presented. Paper V described the asymmetric hydrogenation of diphenylvinylphosphine oxides, di- and trisubstituted vinyl phosphonates. The hydrogenation of diphenylvinylphosphine oxides gives direct access to protected chiral phosphines. The hydrogenated products of vinylphosphonates are highly synthetically useful in pharmaceutical and material chemistry. Hydrogenation of E/Z mixtures of carboxyethyl vinylphosphonates with perfect enantioselectivities was striking in these studies. In paper VI, we have reported the development of a new, highly enantioselective synthetic route to building blocks with CF3 at the chiral center. Several functionalized and unfunctionalized CF3-substituted olefins were hydrogenated with varied degree of success. This methedilogy is useful in the formation of chiral fluorine-containing molecules for a wide range of applications. Paper VII described the hydrogenation of imines using the phosphine-free Cp*Ru/diamine complexes. Chiral version of this reaction was also examined. Despite the modest results, this is the first study to use phosphine-free Cp*Ru/diamine complexes as catalysts for the reduction of C=N double bonds.
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Wegermann, Camila Anchau. "Interações de ligantes imínicos com peptídeos amiloides e metais essenciais implicados em processos neurodegenerativos." Universidade de São Paulo, 2018. http://www.teses.usp.br/teses/disponiveis/46/46136/tde-20072018-093655/.
Full textAbstract:
A terapia de quelação tem sido descrita na literatura como uma ferramenta importante no combate de processos neurodegenerativos como a doença de Alzheimer (AD). Esta doença é caracterizada pela agregação de peptídeos β-amiloides, formando fibrilas, que parece ser induzida ou facilitada em presença de íons metálicos como Cu2+, Zn2+ ou Fe3+. Vários compostos já foram testados e descritos como ligantes competitivos para coordenar e retirar estes íons dos agregados proteicos em condições patológicas, na chamada hipótese da cascata amiloide. O presente projeto visou investigar a reatividade de ligantes imínicos, derivados de oxindóis, na quelação de cobre(II) e zinco(II), numa tentativa de inibir ou evitar a formação de agregados relacionados à AD. Foram sintetizados seis compostos imínicos, sendo duas hidrazonas inéditas: isahim e isahpy e quatro bases de Schiff: isapn, misapn, isaen e misaen, as três últimas também inéditas. Os compostos foram caracterizados por espectroscopia FTIR, RMN, UV/VIS e por análise elementar CHN e espectrometria de massas ESI-MS/MS. Os valores das constantes de estabilidade (log β 2,7 - 5,1) para a formação dos complexos [ML]2+ e do aduto [(Aβ1-16)2•isahim] em solução aquosa foram determinadas por espectroscopia UV/VIS. As formas de interação dos compostos isapn, misapn e isahim com o peptídeo Aβ1-16 foram analisadas por espectroscopia 1H RMN, observando-se uma forte interação com as histidinas His6, His13 e His14 e com os carboxilatos do peptídeo. A eficácia dos ligantes foi testada frente ao processo de inibição da agregação do peptídeo Aβ1-40 na presença e ausência de íons Cu2+ ou Zn2+ por turbidimetria. Estudos de docking e dinâmica molecular suportam que a interação dos ligantes imínicos com o peptídeo Aβ1-16 ocorre nos mesmos sítios de coordenação dos íons metálicos. Os resultados indicam que os compostos aqui estudados podem atuar como eficientes inibidores de agregação dos peptídeos amiloides implicados na AD.Chelation therapy has been considered in the literature an important tool in neurodegenerative processes like Alzheimer disease (AD). This disease is characterized by aggregation of β-amyloid peptides that seems to be improved in the presence of metal ions, particularly copper, zinc and iron. Several compounds have been tested and reported as competitive ligands to withdrawal these metal ions from protein aggregates in pathologic conditions, in the \"amyloid cascade hypothesis\". The present project aims to investigate the reactivity of imine ligands, particularly those derived from oxindoles, in the chelation of copper(II) and zinc(II) ions trying to inhibit or avoid aggregate formation related to AD. Six iminic compounds were synthesized, being two of them hydrazones: isahim and isahpy and four Schiff bases: isapn, misapn, isaen, and misaen. The compounds were characterized by spectroscopic analysis (FTIR, NMR, UV/VIS), elemental analysis CHN and mass spectrometry ESI-MS/MS. The corresponding stability constants (log β 2,7-5,1) for each complex formation [ML]2+ as well as for the adduct [(Aβ1-16)2•isahim] in aqueous solution were determined by UV/VIS spectroscopy. Interactions of compounds isapn, misapn and isahim with the Aβ1-16 peptide were detected and analyzed by 1H NMR spectroscopy, indicating a strong interaction among the compounds and the histidines His6, His13 e His14 as well as the carboxylate residues in the peptides. The ligands efficiency toward the inhibition aggregation process for the Aβ1-40 peptide were evaluated in the presence, and in absence of Cu2+ or Zn2+ ions by turbidimetry. Computational calculations (docking and molecular dynamics) indicated that the interaction of the imine ligand with the Aβ1-16 peptide occurs in the metal coordination sites. The results indicate that these imine compounds studied may act as efficient inhibitors of amyloid peptides implicated in AD.
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Diesen, Jarle Sidney. "Asymmetric Hydrogenations of Imines, Vinyl Fluorides, Enol Phosphinates and Other Alkenes Using N,P-Ligated Iridium Complexes." Doctoral thesis, Uppsala universitet, Avdelningen för organisk kemi, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-8971.
Full textAbstract:
The research described in this thesis is directed toward the efficient, enantioselective synthesis of chiral products that have useful functionality. This goal was pursued through catalytic asymmetric hydrogenation, a reaction class that selectively introduces one or two stereocenters into a molecule in an atom-efficient step. This reaction uses a small amount (often <1 mol%) of a chiral catalyst to impart stereoselectivity to the product formed. Though catalytic asymmetric hydrogenation is not a new reaction type, there remain many substrate classes for which it is ineffective. The present thesis describes efforts to extend the reaction to some of these substrates classes. Some of the products synthesized in these studies may eventually find use as building blocks for the production of chiral pharmaceuticals, agrochemicals, or flavouring or colouring agents. However, the primary and immediate aim of this thesis was to develop and demonstrate new catalysts that are rapid and effective in the asymmetric hydrogenation of a broad range of compounds. Paper I describes the design and construction of two new, related chiral iridium compounds that are catalysts for asymmetric hydrogenation. They each contain an N,P-donating phosphinooxazoline ligand that is held together by a rigid bicyclic unit. One of these iridium compounds catalyzed the asymmetric hydrogenation of acyclic aryl imines, often with very good enantioselectivities. This is particularly notable because acyclic imines are difficult to reduce with useful enantioselectivity. The second catalyst was useful for the asymmetric hydrogenation of two aryl olefins. In Paper II, the class of catalysts introduced into Paper I is expanded to include many more related compounds, and these are also applied to the asymmetric hydrogenation of prochiral imines and olefins. By studying a range of related catalysts that differ in a single attribute, we were able to probe how different parts of the catalyst affect the yield and selectivity of the hydrogenation reactions. Whereas iridium catalysts had been applied to the asymmetric hydrogenation of imines and largely unfunctionalized olefins prior to this work (with varied degrees of success), they had not been used to reduce fluoroolefins. Their hydrogenation, which is discussed in Paper III, was complicated by concomitant defluorination to yield non-halogenated alkanes. To combat this problem, several iridium-based hydrogenation catalysts were applied to the reaction. Two catalysts stood out for their ability to produce chiral fluoroalkanes in good enantioselectivity while minimizing the defluorination reaction, and one of these bore a phosphinooxazoline ligand of the type described in Papers I and II. Enol phosphinates are another class of olefins that had not previously been subjected to iridium-catalyzed asymmetric hydrogenation. They do, however, constitute an attractive substrate class, because the product chiral alkyl phosphinates can be transformed into chiral alcohols or chiral phosphines with no erosion of enantiopurity. Iridium complexes of the phosphinooxazoline ligands described in Papers I and II were extremely effective catalysts for the asymmetric hydrogenation of enol phosphinates. They produced alkyl phosphinates from di- and trisubstituted enol phosphinate, β-ketoester-derived enol phosphinates, and even purely alkyl-substituted enol phopshinates, in very high yields and enantioselectivities.
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Hernández, Olmos Victor. "Diseño de ligandos quirales con estructura de imino- y aminopiridina. Aplicación a la reacción de Henry Enantioselectiva." Doctoral thesis, Universitat de València, 2010. http://hdl.handle.net/10803/41726.
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Cettolin, M. "IRON AND RUTHENIUM CATALYSTS FOR THE REDUCTION OF C=O AND C=N BONDS." Doctoral thesis, Università degli Studi di Milano, 2018. http://hdl.handle.net/2434/543550.
Full textAbstract:
In this PhD thesis recent developments in Iron and Ruthenium Catalysts for the Reduction of C=O and C=N bonds are reported. In Part A the synthesis and reactivity of new iron complexes promoting the reduction of C=O and C=N bonds is reported. The state of the art in homogenous iron catalyzed hydrogenations is introduced in Chapter 1 followed by the results obtained with each class of iron complexes. Chapter 2 shows the synthesis, characterization and reactivity of BINOL-derived tetra isonitrile iron complexes. Two different families were designed differing in the length of the arm bearing the isonitrile group. Those complexes proved to promote asymmetric transfer hydrogenation (ATH) and asymmetric hydrogenation (AH) of acetophenone under basic conditions. Although the initial results were encouraging, the further attempts to improve the performances were mostly ineffective. Lack of activity, enantioselectivity and reproducibility issues convinced us to not proceed further.
Chapter 3 reports a new class of isonitrile-phosphine ligands called PCCP: a chelating system bearing phosphine and isonitrile groups in the same BINOL-derived scaffold. Design, synthesis and characterization of the PCCP ligand are here reported. Once the corresponding iron complex was obtained, ATH of acetophenone was performed but only racemic 1-phenylethanol was yielded. Synthesis of the second generation of PCCP is still undergoing.
Chapter 4 is mainly dedicated to the synthesis and the catalytic properties of the (cyclopentadienone)iron pre-catalyst [bis(hexamethylene) cyclopentadienone] iron complex 81. In the first part of the chapter the synthesis of 81 by the reaction of cyclooctyne with Fe(CO)5 and the investigation of its catalytic properties in C=O bond reduction is reported. As a result of the peculiar reactivity of cyclooctyne, 81 was formed in good yield (56%) by intermolecular cyclative carbonylation/complexation with Fe(CO)5. 81 was fully characterized and its crystal structure was determined by using XRD. Catalytic tests revealed that, upon in situ activation with Me3NO, 81 promotes the hydrogenation of ketones, aldehydes, and activated esters as well as the transfer hydrogenation of ketones and shows a higher activity than the classical “Knölker complex” 30. Studies on the hydrogenation kinetics in the presence of 81 and 30 suggest that this difference in activity is probably caused by the better stability of the 81-derived complex than that of the in situ generated Knölker–Casey catalyst. In the second part of Chapter 4 the first catalytic transfer hydrogenation of non-activated imines promoted by a Fe-catalyst 81 in the absence of Lewis acid co-catalysts is reported. Use of the (cyclopentadienone)iron complex 81 allowed to reduce a number of N-aryl and N-alkyl imines in very good yields using iPrOH as hydrogen source. The reaction proceeds with relatively low catalyst loading (0.5-2 mol%) and, remarkably, its scope includes also ketimines, whose reduction with a Fe-complex as the only catalyst has little precedents. Based on this new methodology, we developed a one-pot catalytic transfer hydrogenation protocol for the reductive amination of aldehydes/ketones, which provides access to secondary amines in high yield without the need to isolate imine intermediates.
Chapter 5 is focused on the catalytic performances of BINOL-derived (cyclopentadienone)iron complexes recently synthesized in our group. Those iron complexes showed good activity in asymmetric hydrogenation of ketones and although the ee values are clearly inferior to the best literature examples of ketone asymmetric hydrogenation, they still represent the best results obtained so far with chiral (cyclopentadienone)iron complexes. Their reactivity in imine reduction (AH and ATH) was investigated and the results are reported. Both pre- and in situ formed imines were screened and promising results were obtained for acetophenone-derived imines.
Part B of this thesis is focused on the use of ruthenium and Trost Ligand as catalyst for asymmetric hydrogenation of ketones. This research was carried out during my Erasmus+ Placement in LIKAT (Leibniz Institute for Catalysis, Rostock, Germany) under the supervision of Prof. Dr. J.G. de Vries and Dr. Sandra Hinze.
In Chapter 6, we described the use of Trost ligand as ligand in the AH of ketones. Trost ligand was screened in the presence of several metal salts and found to form active catalysts when combined with ruthenium sources in the presence of hydrogen and a base. Reaction optimization was carried out by screening different Ru sources, solvents and bases. Under the optimized conditions, the complex formed by combination of Trost ligand with RuCl3(H2O)x in the presence of Na2CO3, is able to promote the AH of several ketones at r.t. with good yields and up to 96% ee. The reaction kinetics measured under the optimized conditions revealed the presence of a long induction period, during which the initially formed Ru species is transformed into the catalytically active complex by reaction with hydrogen.