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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
21

Příprava a katalytické vlastnosti fosfinoferrocenového guanidinu / Synthesis and catalytic properties of phosphinoferrocene guanidine

Bárta, Ondřej January 2016 (has links)
Title: Synthesis and catalytic properties of phosphinoferrocene guanidine Author: Ondřej Bárta Institution: Faculty of Science, Charles University in Prague, Department of Inorganic Chemistry Supervisor: prof. RNDr. Petr Štěpnička, Ph.D. Polar phosphine ligands proved to be useful in homogeneous and biphasic catalysis. Most of these phosphines bears anionic functional groups. On the other hand, functionalization of phosphines by cationic substituents is still quite uncommon, although these functional groups possess properties that could improve catalytic performance of the catalyst. In this regard, nitrogenous bases are particularly attractive due to their inherent basicity and the ability to enter into hydrogen bonding interactions. This thesis describes the synthesis of a novel ferrocene-based phosphine functionalized with guanidine moiety, viz. N-[1′-(diphenylphosphino)ferrocenylmethyl]guanidine (3). This compound was obtained by direct guanylation of 1′-(diphenylphosphino)- 1-(aminomethyl)ferrocene (2) (see scheme). Compound 3 was further used to prepare palladium complexes including the unusual zwitterionic complex [PdCl3(3H)]. The molecular structures of the prepared complexes were determined by X-ray diffraction analysis. Catalytic properties of phosphine 3 and complex [PdCl3(3H)] were...
22

Pd catalysed C-C & C-O bond formation using bis-(dialkyl/diarylphosphino)ferrocene ligands

Milton, Edward J. January 2010 (has links)
A brief introduction explaining phosphine ligand properties, Pd catalysed cross-coupling reactions; the importance of the steps involved in the catalytic cycle (oxidative addition, transmetalation & reductive elimination), mechanistic studies and a comparison of various reactions will give an overview of important cross-coupling reactions and their limitations. The development of a “super-concentrated” (5M) Pd catalysed Kumada type coupling reaction has been developed for coupling a range of aryl bromide and chloride substrates with the Grignard reagents ((p-CF₃-C₆H₄)MgBr)) and PhMgBr in methyl-tetrahydrofuran (Me-THF). Using a range of bidentate ligands such as bis-phosphinoferrocenyl ligands, good conversions were achieved using small amounts of solvent; up to 10 times less than typical procedures in THF. The unsymmetrical Pt complexes of the form [Pt(P-P)Br₂], [Pt(P-P)(Ph)Br] and [Pt(P-P)Ph₂] have been synthesised and characterised. The variations of substituents on the ligand system and the steric bulk have been shown to have a dramatic effect on the rate of transmetalation. The results provide one explanation why 1,1’-bis(di tert-butylphosphino)ferrocene (dtbpf), an excellent ligand for certain Suzuki reactions, is quite poor in reactions where transmetalation is more difficult. Palladium dichloride complexes of the ferrocenylphosphine based ligands 1,1’-bis- (diphenylphosphino)ferrocene (dppf), 1,1’-bis-(diisopropylphosphino)ferrocene (dippf) and 1,1’-bis-(di-tert-butylphosphino)ferrocene (dtbpf) have been shown to be active in the Hiyama cross-coupling of p-bromoacetophenone and vinyltrimethoxysilane (CHCH₂Si(OMe₃)) in the presence of TBAF under thermal heating and microwave conditions. Ligands with the optimum balance for promoting the transmetalation, oxidative addition and reductive elimination steps along the reaction pathway have been identified. Competition experiments are consistent with slow transmetalation being an issue with the Hiyama reaction relative to the Suzuki coupling. A novel protocol has been developed for the synthesis of aryl-alkyl ethers via C-O bond activation under Pd catalysed conditions. Utilising the unsymmetrical 1-bis-(ditertbutyl-1’- bis-diphenylphosphino)ferrocene (dtbdppf) under optimised conditions with silicon based nucleophiles and NaOH or TBAF as an activator, the formation of methyl, ethyl, n-propyl and n-butyl ethers with a range of aryl halides was achieved in good yield.
23

Advances in the coordination chemistry of nitroaromatic phosphines : synthesis and supramolecular chemistry of alkyl/aryl carbo-benzene derivatives / Avancées en chimie de coordination des phosphines nitroaromatiques : synthèse et chimie supramoléculaire de dérivés alkyl - aryl-carbo-benzènes

Zhu, Chongwei 14 December 2017 (has links)
Le manuscrit est divisé en six chapitres et deux parties indépendantes, la première étant consacrée à l'étude de l'effet de substituants nitro sur des ligands phosphines aromatiques (L). Une série de (N-phényl-benzimidazol-1-yl)diphénylphosphines substituées par 1 à 3 groupes nitro à différentes positions des noyaux N-phényle et benzimidazolyle, a été synthétisée, et comparée au parent non nitré et à l'homologue N-méthyl-benzimidazolium cationique. Dans les complexes trans-L2RhICl(CO) correspondants, des variations faibles mais systématiques de la fréquence d'élongation C=O IR et du déplacement chimique RMN 103Rh fournissent une quantification empirique des effets régio-spécifiques des substituants nitro sur le caractère donneur global du ligand. Les produits secondaires dinucléaires (µ-CO)(LRhCl)2 donnent des cristaux de clathrate uniques à teneur élevée (6,7:1) en solvate de dichlorométhane. La deuxième partie, regroupant cinq chapitres, concerne l'étude de nouveaux types de carbo-mères fortement p-conjugués, principalement conçus pour pallier la faible solubilité limitante du noyau carbo-benzène. La synthèse et la caractérisation des hexaaryl-carbo-benzènes de référence sont revisitées. Une voie de synthèse en 12 étapes améliorée du dérivé hexaphényle connu et de l'homologue p-bis-3,5-di-tert-butylphényle est décrite. Les deux carbo-benzènes ont été entièrement caractérisés, en particulier par analyse par diffraction des rayons X et par électrochimie. Leur utilisation dans les cellules solaires photovoltaïques organiques s'est avérée freinée par leur faible solubilité empêchant la formation de couches minces de haute qualité. Le troisième chapitre porte sur une série de p-dialkyl-tétraphényl-carbo-benzènes à deux chaînes aliphatiques R = CnH2n +1, n = 2, 4, 8, 14, 20. Leur synthèse basée sur l'addition nucléophile de RMgBr sur la [6]péricyclynedione clé conduit à la fois aux dialkyl- et mono-alkyl-carbo-benzènes réduits, le processus de réduction étant supprimé en utilisant un réactif RLi/CeCl3. Une augmentation spectaculaire de la solubilité dans les solvants chlorés a été observée pour n = 8. Un empilement p-p direct des cycles en C18, guidé par les forces de dispersions aliphatiques, a été montré pour la première fois dans la structure cristalline du dérivé bis-tétradécyle, appuyant l'existence de l'allotrope du carbone 3D ?-graphityne (carbo-mère putatif du graphite). Le quatrième chapitre décrit deux trialkoxyaryléthynyl-tétraphényl-carbo-benzènes et l'étude des propriétés mésogènes de l'un d'entre eux. Une mésophase rectangulaire colonnaire, mise en évidence à 115 °C par des analyses DSC, POM et PXRD, ouvre des perspectives pour une étude systématique des cristaux liquides apparentés. Les constantes du réseau 3D sont cohérentes avec les images STM 2D du carbo-mésogène sur HOPG. Le cinquième chapitre décrit trois carbo-mères de squelette de bis- et ter-phényles, conçus pour leur relation aux fils moléculaires OPP ou OPE. Un carbo-terphényle a montré un très faible potentiel de réduction (-0,39 V/SCE), sans précédent en série carbo-mère. Dans le dernier chapitre, de nouveaux types de carbo-mères sont illustrés: les carbo-barrélènes et les carbo-stilbènes. Leur préparation repose sur l'addition de triyne dinucléophiles sur un ou deux équivalents d'un précurseur [6]péricyclyne (di)one. Dans la série tricyclique, deux carbo-barrélènes non macro-aromatiques et un dérivé bis-butatriénique partiellement réduit, se sont révélés suffisamment stables pour permettre une caractérisation complète, y compris par cristallographie. Le rôle de cage d'un carbo-barrélène vis-à-vis de petites molécules telles que NH4+, même si elle n'a pas encore été clairement établie, a été étudiée théoriquement et expérimentalement. Les carbo-stilbènes ont été obtenus sous forme de mélanges. En l'absence d'analyse cristallographique, ils ont été attribués aux diastéréoisomères cis et trans sur la base de la spectroscopie RMN 1H et des calculs DFT. / The manuscript is divided into six chapters and two independent parts, the first part being dedicated to the investigation of the effect of nitro substituents on aromatic phosphine ligands (L). A series of (N-phenyl-benzimidazol-1-yl) diphenylphosphines substituted with 1 to 3 nitro groups at different positions of the N-phenyl and benzimidazolyl cores, were synthesized, and compared with the non-nitrated parent and cationic N-methyl-benzimidazolium counterpart. In the corresponding trans-L2RhICl(CO) complexes, prepared in two steps and fully characterized, moderate but systematic variations of the C=O IR stretching frequency and 103Rh NMR chemical shift provide an empirical quantification of regio-specific effects of the nitro-substituents on the global donating character of the P-ligand. Dinuclear (µ-CO)(LRhCl)2 side-products were shown to give unique clathrate crystals with a high content (6.7:1) of dichloromethane solvate. The second part, gathering five chapters, concerns the study of new types of highly p-conjugated carbo-mers, primarily devised to palliate the limiting poor solubility of the aromatic C18 carbo-benzene core. The synthesis and characterization of reference hexaaryl-carbo-benzenes are revisited. An improved 12-step synthetic route to the long known hexaphenyl derivative and p-bis-3,5-di-tert-butylphenyl homologue is described. Both carbo-benzenes were fully characterized, in particular by X-ray diffraction analysis and electrochemistry. Their use in organic photovoltaic solar-cells was found to be hampered by their very low solubility preventing the formation of high quality thin films. The third chapter focusses on a series of p-dialkyl-tetraphenyl-carbo-benzenes with two aliphatic chains R = CnH2n+1, n = 2, 4, 8, 14, 20. The synthetic route based on nucleophilic addition of RMgBr to a key [6]pericyclynedione ultimately led to both the dialkyl- and reduced mono-alkyl-carbo-benzenes, the reduction process being found suppressed by using a RLi/CeCl3 reactant. A dramatic enhancement of solubility in chlorinated solvents was observed for n = 8. A direct p-p stacking of C18 rings, driven by aliphatic dispersions forces, could be evidenced for the first time in the X-ray crystal structure of the bis-tetradecyl derivative, giving experimental support to the existence of the a-graphityne 3D carbon allotrope (putative carbo-mer of graphite). The fourth chapter describes two trialkoxyarylethynyl-tetraphenyl-carbo-benzenes and the study of the mesogen properties of one of them. A columnar rectangular mesophase, evidenced at 115 oC by DSC, POM and PXRD analyses, opens prospects for a systematic study of related liquid crystals. The 3D lattice constants are consistent with 2D STM images of the carbo-mesogen deposited on HOPG. The fifth chapter reports on three skeletal carbo-mers of bis- and ter-phenyls, devised for their acquaintance with OPP or OPE molecular wires. A carbo-terphenyl was found to exhibit a very low first reduction potential (-0.39 V/SCE), unprecedented in the carbo-mer series. In the last chapter, new types of carbo-mers are exemplified: carbo-barrelenes and carbo-stilbenes. Their preparation relies on the addition of triyne dinucleophiles to either one or two equivalents of a [6]pericyclyne(di)one precursor. In the tricyclic series, two non-macroaromatic carbo-barrelenes and one partially reduced bis-butatrienic derivative, both containing two sp3-C bridgeheads, were found to be sufficiently stable to allow full characterization, including by crystallography. The cage-ability of a carbo-barrelene toward small molecules such as NH4+, albeit not clearly proven yet, was investigated both theoretically and experimentally. The carbo-stilbene product was evidenced as an unseparated mixture of two isomers. In the absence of crystal of suitable quality for crystallography, they were assigned to the cis and trans diastereoisomers on the basis of 1H NMR spectroscopy and DFT calculations.
24

Příprava a katalytické vlastnosti ferrocenofanových fosfinů / Synthesis and catalytic properties of ferrocenophane phosphines

Škoch, Karel January 2012 (has links)
6 Title: Sythesis and catalytic properties of ferrocenophane phosphines Author: Karel Škoch Institution: Faculty of Science, Charles University in Prague, Department of Inorganic Chemistry Supervisor: prof. RNDr. Petr Štěpnička, Ph.D. Keywords: ferrocene, ferrocenophane, phosphine ligands, palladium, asymetric catalysis, aza- Morita-Baylis-Hillman reaction, asymetric allylic alkylation Abstract: This Thesis describes the preparation of five sterically and electronically different ferrocene phosphines, (R)-1,1'-[1-(diarylphosphino)propan-1,3-diyl]ferrocenes (R)-1a-e, and a study into their coordination and catalytic properties. The key precursor of the phosphine synthesis, chiral alcohol (R)-2, was prepared according to the procedure described in the literature. Alcohol (R)-2 was converted with retention of configuration to diarylphosphines (R)-1a-e in one-step reaction with trimethylsilylchloride and sodium iodide and then with the corresponding diarylphosphine. Phosphines 1a-e were characterized by NMR and MS methods. For the basic representative 1a the following palladium(II) complexes were prepared: [PdCl(LNC )(1a)] (10, LNC = 2-[(dimethylamino)methyl]phenyl-C1 ,N) and trans- [PdCl2(1a)2] (9a). In addition, the isomeric complex cis-[PdCl2(1a)2] (9b) was isolated from the reaction mixture after catalytic...
25

Ancillary Ligand Effects On The Anticancer Activity Of Ruthenium(II) Piano Stool Complexes

Das, Sangeeta 09 1900 (has links)
The thesis “Ancillary Ligand Effects on the Anticancer Activity of Ruthenium (II) Piano Stool Complexes” is an effort to design better antitumor metallodrugs based on ruthenium(II) complexes with various H-bond donor/acceptor ligands and to understand their mechanism of action. Chapter 1 presents a brief review of metallodrugs and their mechanism of action. Different classes of metallodrugs are discussed. A short discussion on ruthenium based anticancer drugs and their established mechanism of action is also included in this chapter. Chapter 2 deals with the synthesis, characterization and anticancer activity of Ru(II) complexes with P(III) and P(V) ligands. The effect of a strong hydrogen bond acceptor on the cytotoxicity of the complexes has been investigated which allows comparison of complexes with ligands possessing a strong hydrogen bond donor or hydrogen bond acceptor. Partial oxidation of the tertiary phosphine ligands leads to a decrease in cytotoxicity of the ligand, while coordination to ruthenium resulted in a significant increase in the cytotoxicity. A molecular mechanism of action for these complexes was suggested on the basis of various biophysical studies. These complexes bind DNA through non-intercalative interactions which lead to the destabilization of the double helix of the DNA and also unwinding of the negatively supercoiled DNA. Results show that the presence of a hydrogen bond acceptor on the ligand is not capable of enhancing interactions with DNA in comparison with hydrogen bond donor groups. Cellular studies of these complexes showed that inhibition of DNA synthesis and apoptosis occur on treatment with these complexes. Interestingly, these complexes are found to be not only cytotoxic but also antimetastatic. Chapter 3 deals with the synthesis, characterization and anticancer activity of Ru(II) complexes with biologically active S containing heterocyclic ligands and their mechanistic study. Complexation of ruthenium with mercaptobenzothiazole (MBT) gave the most cytotoxic complex (H3) in the series. Heterocyclic Ru(II) complexes behave differently as evidenced by cellular and biophysical studies. Unlike phosphine complexes, H3 shows biphasic melting of DNA at higher concentrations which suggests two different types of interaction with DNA. Chapter 4 deals with synthesis and characterization of water soluble multiruthenated hydrophilic ruthenium(II) complexes with urotropine. An increase in cytotoxicity and binding affinity has been observed with increase in the number of ruthenium atoms per molecule. The complex with three ruthenium atoms showed the best activity. However cytotoxicity of the complexes decreases with decrease in the lipophilicity of the complexes. Chapter 5 describes studies on the interaction of Ru complexes with water, ss-DNA, AMP, GMP and GSH by various spectroscopic techniques. Hydrolysis of Ru-Cl bond in the complexes correlates with the cytotoxicity. Chapter 6 reports the summary of the observations of the thesis and the future prospects of metallodrugs.
26

Nickel mediated negishi and oxidative couplings / Couplages de negishi et couplages oxydants à base de complexes de nickel

Ohleier, Alexia 14 March 2017 (has links)
Ce projet de recherche porte sur la formation de nouvelles liaisons C-C et la production de produits chimiques valorisables grâce à l'utilisation de complexes de nickel chélatés. La première partie de cette thèse est dédiée à des complexes bis-phosphines de nickel employés comme catalyseurs pour le couplage croisé de Negishi. Le précatalyseur [(dcpp)Ni(n2-toluene)] (dcpp = 1,3 bis(dicyclohexylphosphino)propane) permet de coupler efficacement des chloro-arènes avec des organozinciques en utilisant de faibles charges catalytiques (0,2 mol% - 0,1 mol%) et des conditions douces (THF, 60 °C). Une étude mécanistique fondée sur des réactions stœchiométriques et des calculs DFT prouve la présence d'intermédiaires Ni(0)/Ni(II) au cours de la catalyse et exclut tout passage par un mécanisme de type Ni(I)/Ni(III). La seconde partie de ce travail porte sur le couplage oxydant entre l'éthylène et le CO2 sur des complexes de nickel chélatés par des bis-phosphines ou des bis-NHC. Une étude cinétique de l'équilibre entre [(dcpp)Ni(C2H4)] et [(dcpp)nickelalactone] a été réalisée. Le complexe [(dcpp)nickelalactone] peut ensuite être réduit et fonctionnalisé en dérivé du propanol en présence de pinacolborane. Des études mécanistiques et catalytiques préliminaires ont eté menées. De plus, de nouvelles méthodologies de synthèses ont été développées afin d'obtenir les premiers complexes [(bis-NHC)Ni(C2H4)] et [(bis-NHC)nickelalactone]. / The aim of this research project is to promote the formation of new C-C bonds and the production of valuable chemicals by using chelated nickel complexes. The first part of this thesis is dedicated to [nickel(bis-phosphine)] complexes employed as catalysts for Negishi cross coupling reactions. Designed Ni(0) precatalyst [(dcpp)Ni(n2-toluene)] (dcpp = 1,3-bis(dicyclohexylphosphino)propane) promotes efficiently the Negishi cross coupling between aryl chlorides and phenylzinc chloride derivatives at low catalyst loadings (down to 0.2 mol% - 1 mol%) under mild conditions (THF, 60°C). Mechanistic investigations relying on stoichiometric reactions and DFT calculations prove the involvement of Ni(0)/Ni(II) intermediates rather than Ni(I)/Ni(III) species during the catalysis. The second part of this work deals with the oxidative coupling between ethylene and CO2 at bis-phosphine and bis-NHC chelated nickel complexes for the production of value-added chemicals. The equilibrium between [(dcpp)Ni(C2H4)] and [(dcpp)nickelalactone] has been investigated by kinetic studies. The subsequent cleavage of [(dcpp) nickelalactone] by pinacolborane leads to its reductive functionalization into a propanol derivative. Preliminary mechanistic and catalytic investigations have been undertaken. Moreover, new methodologies are provided for the synthesis of the first [(bis-NHC)Ni(C2H4)] and [(bis-NHC)nickelalactone] complexes.

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