Dissertations / Theses on the topic 'Palladium'
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Bangun, Nimpan. "NMR study of palladium methoxide and palladium carbomethoxide complexes." Thesis, This resource online, 1993. http://scholar.lib.vt.edu/theses/available/etd-12052009-020137/.
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El, Allam Driss. "Les enthalpies de formation des alliages liquides : palladium-nickel, palladium-gallium, palladium-indium, nickel-gallium, nickel-indium, palladium-nickel-gallium et paladium-nickel-indium." Aix-Marseille 1, 1989. http://www.theses.fr/1989AIX11239.
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A l'aide d'un calorimetre tres haute temperature (1000c
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Oh, Seung-Hoon. "Low-temperature catalytic oxidation of carbon monoxide over palladium metal, hydrous palladium oxides, and anhydrous palladium oxides." [Gainesville, Fla.] : University of Florida, 2005. http://purl.fcla.edu/fcla/etd/UFE0013045.
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McNicholl, Ruth-Anne. "A study of hydrogen interactions with palladium and palladium alloys." Thesis, Queen's University Belfast, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.334511.
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Frey, Karin Marita Grossen Johannes Michael. "Untersuchung der Korrosion von Silber, Palladium und Silber-Palladium-Legierungen /." [S.l : s.n.], 1987. http://www.ub.unibe.ch/content/bibliotheken_sammlungen/sondersammlungen/dissen_bestellformular/index_ger.html.
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Kim, Jeha. "Structural and elastic properties of silver-palladium and copper-palladium superlattices." Diss., The University of Arizona, 1993. http://hdl.handle.net/10150/186275.
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I prepared Ag/Pd and Cu/Pd superlattices using both sputtering and molecular beam epitaxy. For the Ag/Pd (t(Ag):t(Pd) = 1:1) superlattices, I observed two distinctive behaviors in the structural coherence length ξ as a function of modulation wavelength Λ. Using Brillouin light scattering (BLS) I observed a 50% enhancement of the shear elastic constant c₅₅ and a 16% increase of c₁₁ with decreasing Λ. Annealing study showed that a high structural order of the films in the growth direction was strongly correlated to the increase of c₅₅. For the 3:1 and 1:3 Ag/Pd samples, I also observed a monotonic increase of the Rayleigh velocity υ(R) (or c₅₅) with decreasing Λ and similar behavior in the structural coherence length to the 1:1 samples. In conclusion, the recrystallization of the alloy and the formation of extended interfaces by intermixing at the Ag-Pd interfaces are responsible for a large enhancement of c₅₅. Using BLS for the Cu/Pd superlattices, I observed a 24% decrease of c₅₅ as Λ was decreased to ∼30-40 Å, followed by a rapid increase for smaller Λ. The observed homogeneous strain in the growth direction showed a strong relationship with c₅₅. The strain was localized at the interface and the Cu/Pd films were in compressive stress for Λ < 38 Å. In conclusion, a localized strain at the interfaces in Cu/Pd is related to the softening in c₅₅. The measurements of in-plane lattice spacing d[220] indicated a structural transformation of the films at Λ = 14 Å from an incoherent to a coherent structure. However, the in-plane strain did not show any relationship with the softening of c₅₅. For single crystalline Cu/Pd superlattices, well-defined RHEED streaks showed incommensurate growth of Cu(111) on Pd(111) layer. The measured shear elastic constant c₅₅ showed a 26% decrease with respect to the largest Λ film with a peak at Λ ≃ 40 Å. Unlike the sputtered films, while c₅₅ decreases by 26% with decreasing Λ, the Cu/Pd films show no change in d(avg)[111] for Λ > 40 Å. I observed no in-plane anisotropies in υ(R) as predicted from theory for single crystal films.
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Zuideveld, Martin Alexander. "Solvolysis of palladium-carbon bonds in palladium(II) complexes containing diphosphine ligands." [S.l. : Amsterdam : s.n.] ; Universiteit van Amsterdam [Host], 2001. http://dare.uva.nl/document/60731.
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Todorova, Mira. "Oxidation of Palladium surfaces." [S.l.] : [s.n.], 2004. http://deposit.ddb.de/cgi-bin/dokserv?idn=971639868.
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Williamson, Anna Maria. "Studies on novel palladium." Thesis, Imperial College London, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.252246.
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Sparkes, Robert P. "Carbocations in palladium crystals." Thesis, University of Oxford, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.249213.
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Sukirthalingam, Sukanthini. "Palladium catalysed cyclisation processes." Thesis, Queen's University Belfast, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.335444.
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Morris, James Alan. "Palladium-ruthenium bimetallic cascades." Thesis, University of Leeds, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.405707.
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Ostovar, Peyman. "Palladium-catalysed neuroleptic synthesis." Thesis, Imperial College London, 1989. http://hdl.handle.net/10044/1/47601.
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Rojas, Anthony J. (Anthony Jose). "Palladium reagents for bioconjugation." Thesis, Massachusetts Institute of Technology, 2018. http://hdl.handle.net/1721.1/120905.
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Thesis: Ph. D., Massachusetts Institute of Technology, Department of Chemistry, 2018.Cataloged from PDF version of thesis.
Includes bibliographical references.
physicochemical properties in comparison to their linear counterparts. Here we detail a method for a divergent macrocyclization of unprotected peptides by crosslinking two cysteine residues with bis-palladium organometallic reagents. These synthetic intermediates are prepared in a single step from commercially available aryl bis-halides. Two bioactive linear peptides with cysteine residues at i, i + 4 and i, i + 7 positions, respectively, were cyclised to introduce a diverse array of aryl and bi-aryl linkers. These two series of macrocyclic peptides displayed similar linker-dependent lipophilicity, phospholipid affinity, and unique volume of distributions. Additionally, one of the bioactive peptides showed target binding affinity that was predominantly affected by the length of the linker. Collectively, this divergent strategy allowed rapid and convenient access to various aryl linkers, enabling the systematic evaluation of the effect of appending unit on the medicinal properties of macrocyclic peptides. Chapter 2: We report the use of a sulfonated biarylphosphine ligand (sSPhos) to promote the chemoselective modification of cysteine containing proteins and peptides with palladium reagents in aqueous medium. The use of sSPhos allowed for the isolation of several air-stable and water-soluble mono- and bis-palladium reagents, which were used in an improved protocol for the rapid S-arylation of cysteines under benign and physiologically relevant conditions. The cosolvent-free aqueous conditions were applied to the conjugation of a variety of biomolecules with affinity tags, heterocycles, fluorophores, and functional handles. Additionally, bispalladium reagents were used to perform macrocyclization of peptides bearing two cysteine residues. Chapter 3: The synthesis of palladium oxidative addition complexes of unprotected peptides is described. Incorporation of 4-halophenylalanine into a peptide during solid phase peptide synthesis allows for subsequent oxidative addition at this position of the unprotected peptide upon treatment with a palladium precursor and suitable ligand. The resulting palladium-peptide complexes are solid, storable, water-soluble, and easily purified via high-performance liquid chromatography. These complexes react rapidly with thiols at low micromolar concentrations in an aqueous buffer, offering an efficient method for bioconjugation. Using this strategy, peptides can be rapidly functionalized with small molecules to prepare modified aryl thioether sidechains. Additionally, peptide-peptide and peptide-protein ligations are demonstrated under dilute aqueous conditions.
by Anthony J. Rojas.
Ph. D.
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Li, Meiling. "Palladium catalysed allene carbocyclisation." Thesis, University of Oxford, 2010. http://ora.ox.ac.uk/objects/uuid:747420b6-c11f-451c-83c7-fa9fca5f7752.
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In this thesis, firstly, a Pd-catalysed diastereoselective carbocyclisation of allenes with aryl halides or vinyl iodides was designed and developed to form arylative or vinylative spirolactam compounds. High yields and diastereoselectivities were obtained in the presence of Pd2(dba)3/dppe and K2CO3 in DMSO at 70 °C, particularly when spiropiperidin-2-ones were formed. The method is simple to perform and broad in scope. Having established the diastereoselective methodology for the arylative or vinylative allene carbocyclisation, a Pd-catalysed enantioselective version was developed by using bisoxazolines as chiral ligands. Aryl halides and vinyl iodides were investigated in this carbocyclisation. High yields and enantioselectivities were obtained in the presence of Pd(OAc)2, a bisoxazoline ligand L7d derived from L-isoleucine and Ag3PO4 in 1,2-dichloroethane at 70 °C. No olefin isomerisation was observed when cis-vinyl iodides were used. The method is mild, efficient and broad in scope. A palladium catalysed diastereoselective allene carbocyclisation reaction was developed via enamine catalysis and palladium catalysis, which allows for the efficient carbocyclisation of formyl or ketone allenes. Good yields and high diastereoselectivities were obtained in the presence of Pd(OAc)2 and pyrrolidine in toluene at 60 °C when formyl allenes were investigated. The cyclisation is diastereoselective and can also performed as a catalytic asymmetric reaction by using prolinol derivatives as chiral catalysts. Good yields and high diastereo- and enantioselectivities were obtained in the presence of catalyst (S)-L19. Additionally, a boronic acid catalysed ene carbocyclisation of acetylenic dicarbonyl compounds was developed. An attempted transesterification of a β-ketoester substrate bearing a pendent terminal alkyne substituent at the β-position led to the discovery of an efficient 3-nitrobenzeneboronic acid catalysed ene carbocyclisation of acetylenic dicarbonyl compounds. The reaction is easy to perform, efficient, broad in scope and provides a convenient transition metal-free alternative to existing catalytic protocols.
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Sadig, Jessie E. R. "Palladium-catalysed heterocycle synthesis." Thesis, University of Oxford, 2012. http://ora.ox.ac.uk/objects/uuid:c9608957-d215-4a15-87e3-5871c1391946.
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Chapter 1 is a literature review of selected palladium-catalysed aryl C-N and C-S bond forming reactions. The application of these reactions to the synthesis of heterocycles is also discussed. Chapter 2 highlights the importance of the benzimidazole motif and gives a brief discussion of the existing routes to this scaffold. The utility of N-(o-halophenyl)imidoyl chlorides and imidates as precursors to heterocycles is demonstrated in a palladium-catalysed reaction with N-nucleophiles to afford benzimidazole products. Chapter 3 provides a brief introduction to the synthesis of benzothiazoles and describes efforts towards the use of our established substrates for the preparation of these heterocycles. This is achieved via reaction of N-(o-chlorophenyl)imidoyl chlorides with a sulfur nucleophile in a metal-free process. Chapter 4 is a literature review of palladium-catalysed carbonylation chemistry with specific focus on aminocarbonylation and thiocarbonylation reactions of aryl halides. Heterocycle syntheses which employ such carbonylative methods are also discussed. Chapter 5 describes existing protocols for the synthesis of quinazolinones. A novel palladium-catalysed synthesis of these heterocycles from the reaction of our imidate substrates with an amine and carbon monoxide is described. This further demonstrates their utility as general heterocycle precursors
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Hollingworth, Charlotte. "Palladium mediated allylic fluorination." Thesis, University of Oxford, 2013. http://ora.ox.ac.uk/objects/uuid:8c61b9e9-b143-4c5e-b151-7e62bf4ecc03.
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In this thesis, the construction of the allylic fluorides under palladium catalysis was investigated. Chapter 1 provides a general introduction to organofluorine compounds and the use of palladium for the formation of both Csp2- and Csp3-F bonds. The aims of the thesis are presented. In Chapter 2 the identification that a p-nitrobenzoate is the optimum leaving group under Pd-catalysis to give allyl fluorides is described. A range of allylic fluorides was synthesized in 35->95% yield using the nucleophilic fluorinating reagent, TBAF(tBuOH)4. To further develop this transformation we have examined the effect of a variety of leaving groups and phosphine ligands. This methodology led to the development of the first transition metal mediated C-18F bond formation. The development of Ir-catalysed fluorination of allylic carbonates to give allylic fluorides is also discussed. This system provided access to branched, E- and Z-linear allylic fluorides in a regioselective manner. This methodology was also translated to 18F radiochemistry. In Chapter 3 the synthesis of allylic fluorides via a C-H functionalisation with Pd and nucleophilic source of fluorine was investigated. Comprehensive screening of Pd sources, fluoride reagents and additives was performed. The presence of a quinone was found to be crucial for this transformation. Chapter 4 describes the synthesis and characterization of a series of allylpalladium(II) complexes and their subsequent reactivity towards a range of electrophilic fluorination reagents. Chapter 5 gives full experimental procedures and characterization data for all compounds.
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Setayandeh, Samaneh S. "Hydrogen Properties in Palladium." Thesis, Griffith University, 2021. http://hdl.handle.net/10072/404154.
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In this project the palladium-hydrogen system was investigated, using computational and experimental approaches. Computational modelling, employing ab initio calculations based on density functional theory (DFT), were done with the Quantum Espresso package, to investigate the electronic and phonon properties of PdH and its superabundant vacancy phase (Pd3VacH4), assuming that octahedral or tetrahedral lattice interstices are occupied by hydrogen, and to relate these to important physical properties, in particular the atomic volume of hydrogen in Pd and the superconducting transition temperature of PdH.
The driver for the computational part of this project was the history of DFTbased publications in the literature predicting such widely different phonon band structures that confident interpretations of the results really could not be made. Therefore, a systematic approach was followed to compare the calculated electron and phonon properties of PdH and Pd3H4 with six different DFT schemes, within the harmonic approximation. The results highlighted the excellent agreement for the electron band structure and the sensitivity of the phonon properties to the details of the schemes employed, and also confirmed the need to include anharmonicity of the H potential to obtain realistic phonon results.
The calculations predicted dynamic instability for octahedral Pd3VacH4, although the calculated lattice constant agreed with the estimated zerotemperature experimental value. This structure requires new calculations accounting for anharmonicity. The calculated lattice constant for Pd3VacH4 in the tetrahedral case was larger than any experimental value, so this alternative, while dynamically stable, is certainly not observed.
While the absolute lattice constant of PdH varied considerably between DFT schemes, it was found that the partial atomic volume of H in Pd, a relative measure, was rather robust against differing computational approaches. A significant discrepancy was demonstrated between the average DFT predictions for the atomic volume assuming octahedral-only interstitial occupancy and that calculated from neutron diffraction measurements on Pd and PdHx. Calculations for PdH with mixed octahedral and tetrahedral occupancy showed that PdH containing around 20% tetrahedral H would have the correct atomic H volume.
Within the harmonic approximation, the calculated superconducting transition temperature of octahedral PdH varied by a factor of nearly three across the six DFT schemes employed. This shows that a reliable DFT approach is needed before attempting to account for anharmonicity of the H potential. In the tetrahedral case, less discrepancy was observed between the characteristic measures of superconductivity, due to the smaller contribution of high-frequency optical branches to the electron-phonon coupling parameter, but the actual values predicted for the transition temperature should be relatively reliable because the tetrahedral site, being relatively small, should be more nearly harmonic than the octahedral site. The transition temperatures calculated for tetrahedral PdH were higher than those measured experimentally, making partial tetrahedral occupancy an interesting possibility from the superconductivity point of view.
For the experimental part of this project, high-resolution gravimetry was used to survey the pressure-composition behaviour of PdHx and PdDx formed above their critical points and cooled to room temperature, to determine if this preparation route leads to extra hydrogen and deuterium absorption compared to passage through the two-phase region. It was found that supercritical absorption shifted the low-pressure portion of the desorption isotherm towards higher concentration. However, the isotherms were shifted towards the expected H/D concentration by cycling, apparently due to introducing misfit dislocations in the sample. Hydriding the sample at room temperature and heating it to 300 ℃ under pressure instead of first heating to 300 ℃ and then loading with hydrogen unexpectedly shifted the supercritcal isotherms at 300℃ to lower pressure, pointing to a further and previously unobserved influence of defects on the absorption-desorption behaviour.Thesis (PhD Doctorate)
Doctor of Philosophy (PhD)
School of Environment and Sc
Science, Environment, Engineering and Technology
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Powell, Luke Haydn William. "Palladium-catalysed enantioselective desymmetrisations." Thesis, University of Bath, 2005. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.425803.
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Tong, Xiu Qiang. "Lattice strain induced (Gorsky effect) diffusion of hydrogen in palladium and palladium alloys." Thesis, Queen's University Belfast, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.334683.
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Rayee, Quentin. "Dépôts électrochimiques d’argent, de palladium et d’alliages argent-palladium en solvants eutectiques profonds." Doctoral thesis, Universite Libre de Bruxelles, 2020. http://hdl.handle.net/2013/ULB-DIPOT:oai:dipot.ulb.ac.be:2013/303218.
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Le recours aux solvants eutectiques profonds se présente comme une alternative potentielle aux limitations rencontrées en milieux aqueux pour la réalisation de dépôts électrochimiques. La transposition des procédés électrochimiques des milieux conventionnels vers ces nouveaux milieux n’est pas immédiate et nécessite d’entreprendre des études fondamentales visant à comprendre l’impact de la nature des solvants eutectiques profonds sur différents processus survenant à l’interface électrochimique. Dans cette optique, le présent travail examine les mécanismes impliqués dans la formation de dépôts d’argent, de palladium et du mélange Ag-Pd en solvants eutectiques profonds à l’aide de plusieurs techniques voltampérométriques (voltampérométries cyclique, différentielle, alternative, hydrodynamique, à balayage linéaire) et de mesures chronoampérométriques. Le choix du dépôt d’argent a été retenu comme système modèle et a été étendu à la réalisation d’alliage Ag-Pd qui présente un intérêt plus appliqué. Les solvants eutectiques profonds sélectionnés pour cette recherche sont obtenus en mélangeant du chlorure de choline avec de l’urée (ChCl-U) ou avec de l’acide oxalique (ChCl-Ox). Le comportement électrochimique de AgCl en ChCl-U est fortement affecté par la nature de l’électrode. Sur carbone et platine, une importante surtension pour le dépôt à 3D est requise, alors qu’aucune surtension n’est nécessaire sur électrode d’or en raison d’un processus de dépôt à 2D (dépôt en soustension) de l’argent sur l’or. Ce mécanisme de dépôt en sous-tension est peu sensible à la nature du solvant eutectique profond et très similaire à celui obtenu en solution aqueuse avec une concentration équivalente en chlorures. Le recours à des monocristaux a permis d’examiner l’influence de la cristallographie sur le dépôt en sous-tension. Une attention particulière a été portée à la présence de thiourée en milieu ChCl-U et celle-ci affecte profondément les dépôts métalliques d’Ag en modifiant la coordination des espèces Ag(I) et l’adsorption des espèces constitutives du ChCl-U à la surface d’une électrode d’or. Les mesures voltampérométriques du PdCl2 en ChCl-U ont permis de distinguer quatre régions en potentiel où ont lieu respectivement (des potentiels les plus positifs vers les plus négatifs) un dépôt en sous-tension confirmé par des mesures de désorption oxydative de CO, un dépôt à 3D, la formation d’hydrure de palladium (PdHx) et, à des potentiels bien inférieurs, un processus d’inhibition du dépôt. L’utilisation du ChCl-Ox a mis en évidence que la formation de PdHx dépendait du pH apparent du solvant eutectique. L’étude du mélange de AgCl et de PdCl2 a révélé la coexistence de phases distinctes associées à des alliages de différentes compositions formés lors du dépôt électrochimique. Les proportions entre les différentes phases sont très sensibles aux conditions de température, potentiel de dépôt et concentration des précurseurs métalliques, et l’influence de ces différents paramètres est discutée en détail. De plus, un processus de remplacement galvanique de l’argent par le palladium a également été mis en évidence avec l’appui de mesures XPS.Doctorat en Sciences
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Yang, Zhiqiang. "Preparation of palladium, palladium sulfide, cadmium selenide nanoparticles and magnesium oxychloride, magnesium hydroxide nanorods." Diss., Manhattan, Kan. : Kansas State University, 2008. http://hdl.handle.net/2097/891.
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Vicente, Aurélie. "Hydrogénation du citral sur catalyseurs bimétalliques supportés rhodium-germanium, palladium-germanium et palladium-étain." Poitiers, 2008. http://www.theses.fr/2008POIT2338.
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Ce travail est consacré à la préparation de catalyseurs bimétalliques supportés Rh-Ge, Pd-Ge et Pd-Sn pour l’hydrogénation sélective du citral en alcools a,b-insaturés. Pour les catalyseurs à base de Rh, l’étude porte sur l’influence de la nature des sels précurseurs utilisés. L’existence d’interactions entre les deux métaux des différents systèmes bimétalliques est mise en évidence par diverses techniques de caractérisation (EDX, réaction modèle de déshydrogénation du cyclohexane, RTP sous H2, IRTF de CO adsorbé). La réaction d’hydrogénation sélective du citral a montré qu’il est possible de modifier profondément les propriétés de ces métaux par les ajouts Ge et Sn, et ainsi former des alcools insaturés. L’adsorption de CO suivie par IRTF sur les catalyseurs Rh-Ge/TiO2 révèle la formation d’espèces Rh≥1+ avec ajout de Ge, lesquelles permettraient l’activation de la fonction carbonyle du citral. De plus, la présence de chlore issu des sels précurseurs semble être favorable à la formation de ces espèces Rh≥1+ sur ces systèmes bimétalliques. Pour le palladium, une bonne sélectivité en alcools insaturés est obtenue lorsqu’il y a formation d’un alliage de type Pd3M (avec M = Ge ou Sn), formation mise en évidence par différentes caractérisations (RTP et XPS). Cet alliage induit un transfert d’électron de Sn vers Pd constaté aussi bien par IRTF que par XPS, qui peut expliquer une adsorption favorisée de la liaison C=O du citralThis work was devoted to the preparation of supported bimetallic Rh-Ge, Pd-Ge and Pd-Sn catalysts for the selective hydrogenation of citral to its corresponding a,b-unsaturated alcohols. In the case of Rh catalysts, the influence of Rh and Ge salt precursors has been studied. The existence of interactions between the two metals for the different bimetallic systems has been highlighted by several characterization methods (EDX, cyclohexane dehydrogenation reaction, TPR under H2, FTIR of adsorbed CO). The reaction of selective hydrogenation of citral showed that the addition of Ge or Sn to Rh and Pd allowed one to strongly modified the catalytic properties of these metals. The adsorption of CO followed by FTIR on Rh-Ge/TiO2 revealed the formation of Rh≥1+ species due to Ge addition. These species would activate the carbonyl group of citral. Moreover, the presence of chlorine resulting from precursor salts seemed favourable to the formation of these Rh≥1+ species. In the case of Pd catalysts, the different characterizations (TPR and XPS) proved the formation of Pd3M alloy (with M = Ge or Sn). This alloy induced an electron transfer from Sn to Pd, evidenced by FTIR and XPS. The formation of these Pd-Snd+ sites could then explain a favoured adsorption of the carbonyl group of citral, which leads to high selectivity in unsaturated alcohol
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Beyer, Andreas. "Reaktivmembranen aus Polyacrylsäure-Palladium-Verbundsystemen." [S.l.] : [s.n.], 2001. http://deposit.ddb.de/cgi-bin/dokserv?idn=963799169.
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Markmann, Jürgen. "Mikrostrukturuntersuchungen an kaltgewalztem nanokristallinem Palladium." Karlsruhe : FZKA, 2005. http://bibliothek.fzk.de/zb/berichte/FZKA7126.pdf.
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Lindh, Jonas. "Palladium(II)-Catalyzed Coupling Reactions." Doctoral thesis, Uppsala universitet, Avdelningen för organisk farmaceutisk kemi, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-130031.
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Sustainable chemical processes are becoming increasingly important in all fields of synthetic chemistry. Catalysis can play an important role in developing environmentally benign chemical processes, and transition metals have an important role to play in the area of green chemistry. In particular, palladium(II) catalysis includes many key features for successful green chemistry methods, as demonstrated by a number of eco-friendly oxidation reactions catalyzed by palladium(II). The aim of the work presented in this thesis was to develop novel and greener palladium(II)-catalyzed coupling reactions. In striving to achieve this aim, the first open-vessel, room-temperature palladium(II)-catalyzed oxidative Heck reaction, using oxygen from the air as the reoxidant of palladium, was developed. In a further investigation of the palladium(II)-catalyzed oxidative Heck reaction, base-free conditions for the transformation were identified and suitable conditions for microwave-assisted oxidative Heck reactions were established. A convenient and low-cost palladium(II)-catalyzed method for the synthesis of styrene derivatives, by coupling arylboranes with vinyl acetate, was developed. The reaction mechanism was studied using ESI-MS, which enabled the detection of cationic palladium intermediates in ongoing productive reactions, and a plausible catalytic cycle was proposed. In an attempt to make the oxidative Heck and the styrene synthesis reactions more attractive from an industrial point of view, conditions for continuous flow synthesis were identified. The results were generally good and rapid synthesis of the desired products was obtained. The first palladium(II)-catalyzed C–P bond-forming Hirao-type reaction, employing arylboranes instead of the commonly used aryl halides, was developed. An ESI-MS study was performed, and a plausible catalytic pathway was suggested. Finally, a novel method for synthesizing aryl ketones from benzoic acids and nitriles, via palladium(II)-catalyzed decarboxylation of the benzoic acids, was established. Further, the reaction mechanism was studied by ESI-MS and a plausible catalytic route presented.
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Zargarian, Davit. "Palladium-catalyzed carbonylation of alkynes." Thesis, University of Ottawa (Canada), 1992. http://hdl.handle.net/10393/7555.
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This thesis describes the palladium-catalyzed carbonylation of alkynes with formic acid. Terminal alkynes react with formic acid in the presence of catalytic amounts of Pd(OAc)$\sb2$ and suitable phosphine ligands (120 psi of CO gas pressure, 100-110$\sp\circ$C) to produce the unsaturated carboxylic acids CR(COOH)=CH$\sb2,$ 1, and (E)-CHR=CH(COOH), 2. The combined yields of 1 and 2 for various R's range from 60 to 90%. The regioselectivity is approximately 90:10 in favour of 1 when R is a phenyl or a straight chain alkyl group; 2 is the favoured product when R is t-Bu and the exclusive one when R is SiMe$\sb3.$ Under similar conditions, internal alkynes react with formic acid to produce the unsaturated carboxylic acids (E)-CR(COOH)=CHR$\sp\prime$, 3, and (E)-CHR=CR$\sp\prime$(COOH), 4, also in 60-90% combined yields. The regioselectivity of this reaction, however, is not as high as for terminal alkynes. Oxalic acid can be used instead of formic acid in both of these reactions. The most suitable phosphine ligands for alkyne hydrocarboxylation in the present system are PPh$\sb3$ and dppb (1,4-bis(diphenylphosphino)butane). In some cases, using a mixture of these two ligands remarkably improves the reaction yields; the implications of such ligand synergism are discussed. On the basis of deuterium labelling studies and other experimental results, a reaction mechanism has been proposed which involves the addition of the O-H bond of formic acid to form a cationic hydrido(alkyne) intermediate. This intermediate is thought to undergo a sequence of reactions, including hydride and CO insertions, to give the acid product and regenerate the active catalyst. Terminal alkynes undergo dicarbonylation upon reacting with formic acid and/or water in a catalytic system consisting of $\rm PdCl\sb2/CuCl\sb2/O\sb2/CO$ (room temperature, atmospheric pressure); the products are monosubstituted maleic anhydrides and the corresponding maleic and fumaric acids in 30-75% combined yields. The product distribution is influenced by both the steric bulk of the alkyne substituent and the amount of water present in the reaction medium. Internal alkynes are unreactive in this system. Among the solvents tested, THF is the most suitable one. Phosphines and phosphites completely inhibit the reaction. In contrast to most systems in which CuCl$\sb2$ acts as the principal oxidant for converting Pd(0) to Pd(II), the role of CuCl$\sb2$ in the present system seems to be secondary to that of oxygen. For instance, modest catalytic turnovers are observed in the absence of CuCl$\sb2$, whereas no catalysis occurs if oxygen is excluded from the system, even in the presence of excess CuCl$\sb2$. These and other observation are rationalized by invoking various oxidation schemes involving oxygen as the main oxidant. The role of CuCl$\sb2$ is thought to be one of facilitating the catalysis by forming a heterometallic Cu/Pd complex.
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Zhao, Jian. "Palladium migrations and aryne annulations." [Ames, Iowa : Iowa State University], 2007.
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Flegeau, Emmanuel Ferrer. "Palladium cross-couplings of oxazoles." Thesis, University of Edinburgh, 2008. http://hdl.handle.net/1842/3171.
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A review covering the literature until April 2008 concerning organometallic reactions to funcionalise oxazoles is described. A protocol for the functionalisation of the oxazole 2- and 4-positions using the Suzuki coupling reaction is described. 2- Aryl-4-trifloyloxazoles undergo rapid, microwave-assisted coupling with a range of aryl and heteroaryl boronic acids in good to excellent yields. The methodology is similarly effective using 4-aryl-2-chlorooxazoles as the coupling partner and has been extended to the synthesis of a novel class of homo- and heterodimeric 4,4- linked dioxazoles. In addition, a regioselective Suzuki-Miyaura cross-coupling of 2,4-dihalooxazoles followed by a Stille coupling has been successfully developed. The procedure affords convergent syntheses of trisoxazoles in high yield and in a minimum number of steps. Furthermore, C-2 direct arylation of oxazoles is discussed. This methodology is extended to the synthesis of C2-C4’ linked bis and tris oxazoles of the type found in the Ulapualide A family of natural products.
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Yusop, Rahimi Muhammad. "Palladium chemistry in chemical biology." Thesis, University of Edinburgh, 2011. http://hdl.handle.net/1842/5734.
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A range of fluorescein derivatives were synthesised via Pd0-mediated cross-coupling chemistry of the mono triflate of fluorescein with a variety of boronic acids and the optical properties of each dye was studied. Among these derivatives, a new multicolour pH–dependant anthofluorescein which was highly sensitive to pH changes and viscosity changes was identified. Work was carried out to explore intracellular catalysis based on the immobilisation of Pd0 nanoparticles on microspheres. The entrapped Pd0 nanoparticles were rapidly taken up by cells, stay harmlessly within the cytoplasm for days and were shown to carry out novel cell-based chemistry. This included an allylcarbamate cleavage and a Suzuki-Miyaura cross-coupling reaction for the in situ generation of a mitochondria-localized “switch-on” fluorophore.
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Dumrongchai, Nuethip. "Palladium Catalyzed Multicomponent Cascade Reactions." Thesis, University of Leeds, 2007. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.487516.
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This Thesis is divided into three parts: Introduction (Chapter 1), Result and Discussion (Chapter 2) and Experimental (Chapter 3). The Introduction (Chapter 1) provides a review of the recent literature relating to the 1,3dipolar cycloaddition reactions. It· covers nitrones, azomethine ylides and azomethine imines. The Result and Discussion. section (Chapter 2) deals with the author's work which is . concerned with developing four novel multicomponent cascade reactions. These are (i) a 3- component cascade involving bifunctional aryl halide! Michael acceptors, allene and arriine or sulphonamide nucleophiles (ii) a 3-component cascade involving bifunctional arylhalide! Michael acceptors, carbon monoxide and primary ~nes (iii) a 4-component cascade involving a bifunctional aryliodide! aldehyde, hydrazines, allene and· a dipolarophile and (iv) a 3-component cascade involving 2-bromomethyl iodobenzene, carbon monoxide and / ' hydrazines. { Cascade (i) and (ii) employ a common bifunctional Michael acceptor! arylhalide and a series of these were prepared all of which had an a, .p- unsaturated amide as the Michael acceptor. In·niost caSe these contained a chiral amide function while enabled the author to study chiral induction and diastereomer product ratios. In series (i) product yields ranged from 54-75% but there was essentially no chiral induction (dr's 1:1-1:1.6). Series (ii) gave a range of interesting isoindolones in 61-78% yield but again there was no significant chiral induction (dr 1:1-1:1.7). In both series we concluded the chiral amide centre is too distant from the site of the newly created chiral centre to have a controlling influence. Series (iii), the 4-component cascade proceeded regia-and stereoselectively in 55-72% yield. The IH NMR spectra of the pyrazolidine products showed line broadening due to N-Ione pair inversion processes which was confirmed by variable temperature IH NMR studies. An approximate inversion barrier of 12-15 Kcals.morl wa~ estimated. The final series, series (iv), was only briefly studi~d with two examples completed in 61-64% yield. .The thesis concludes (Chapter 3) with full experimental details' of all new compounds together with their appropriate physical, spectroscopic and analytical data.
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Cooper, Ian Ronald. "Palladium-indium bimetallic cascade processes." Thesis, University of Leeds, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.401087.
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Marchbank, John David. "Palladium-catalysed cascade ring syntheses." Thesis, University of Leeds, 2004. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.405708.
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Sheridan, Kelly Jane. "Palladium catalysed co/alkyne reactions." Thesis, University of Liverpool, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.428220.
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Cleghorn, Simon John Charles. "Electrocatalytic hydrogenation at palladium electrodes." Thesis, University of Southampton, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.332771.
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Henderson, William Howell. "Palladium-Mediated C-H Activations." The Ohio State University, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=osu1318003095.
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Broderick, Meghann. "Characterization of Stabilized Palladium Nanocatalysts." VCU Scholars Compass, 2010. http://scholarscompass.vcu.edu/etd/2201.
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Metal nanoparticles have received much interest for their application in catalysis due to high surface-to-volume ratios resulting in more available active sites. Ideally these catalysts are heterogeneous and allow for facile separation from the catalytic reaction mixture making them ideal for industrial application. Dispersed metal nanoparticles are explored due to their high reactivity in solution and are stabilized by surfactants and polymers. However, it is difficult to determine whether or not a catalyst is truly heterogeneous as a certain degree of leaching from the metal nanoparticle is inevitable. Determining the mechanisms involved in nanocatalysis is also a challenge. In this study, a series of dispersed palladium nanocatalysts in the Suzuki reaction with phenylboronic acid and bromobenzene were characterized before and after catalysis to determine what changes occur. Samples where characterized before and after the catalytic reaction by XPS, SEM, and EDS to monitor changes in particle size and composition. Reaction mixtures after catalysis were analyzed by ICP-MS for leached palladium species to determine if concentrations were high enough for homogeneous catalysis to take place. The dispersed palladium nanoparticles studied experienced growth during the catalytic process and a significant amount of leaching. XPS analysis indicates the presence of aromatic species on the particle surface after the catalytic reaction. The aromatic species is likely biphenyl, the product of the catalytic reaction, as the presence of boron and bromine was not found in XPS and EDS analysis.
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Švejd, Michal. "Typologie zákazníka nákupního centra Palladium." Master's thesis, Vysoká škola ekonomická v Praze, 2008. http://www.nusl.cz/ntk/nusl-4704.
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Stěžejní částí diplomové práce je vlastní marketingové šetření, které proběhlo v nákupním centru Palladium za asistence společnosti Property Value Solutions, s.r.o., která na výzkum dohlížela a má velký zájem na vyhodnocení výsledků, které budou prezentovány managementu Palladia.
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Boysen, Ryan Bradley. "Development of palladium L-edge X-Ray absorption spectroscopy and its application on chloro palladium complexes." Thesis, Montana State University, 2006. http://etd.lib.montana.edu/etd/2005/boysen/BoysenR0506.pdf.
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X-ray Absorption Spectroscopy (XAS) is a synchrotron-based experimental technique that can provide information about geometric and electronic structures of transition metal complexes with unoccupied d orbitals. Combination of metal L-edge and ligand K-edge XAS has the potential to define the experimental ground state electronic structure. We developed a quantitative treatment for Pd L-edge spectroscopy based on the already established Cl K-edge XAS for a series of chloro palladium complexes, which are precatalysts in numerous organic transformations. We found that Pd-Cl bonds are highly covalent (23% per Cl in [PdC4]2-, 34% per Cl in [PdCl6]2-, and 46% in PdCl2). Dipole integrals for Pd(2p→4d) transitions of 42 eV for Pd(II) and 48 eV for Pd(IV) LIII-edges and 39 eV and 35 eV, respectively, at these Pd oxidation states for the LII-edges were determined. Application of the metal-ligand covalencies and transition dipole integrals by describing the ground state bonding in PdCl2 with bridging Cl ligands was demonstrated. In future studies, a similar approach will be utilized for palladium phosphine, allyl, olefin complexes in order to define their experimental electronic structure and correlate this with their observed reactivity.
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Brits, Johannes Hendrik Wilhelmus Machiel. "Study on the thermodynamics and kinetics of the stripping of palladium from a typical palladium organic." Master's thesis, University of Cape Town, 2005. http://hdl.handle.net/11427/11784.
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Includes bibliographical references.The aim of this thesis was to investigate the thermodynamics and the kinetics of the stripping of palladium from a typical palladium organic. The thesis firstly characterizes the thermodynamic effects of temperature and strip acid normality on the stripping of palladium and secondly investigates the kinetics of the palladium stripping reaction by exploring the effect of impeller speed and type on the overall volumetric mass transfer coefficient. which was the major focus of this thesis.
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Ji, Jianhua. "Regioselective Coupling Reactions of Diiodophenol Derivatives." Thesis, University of North Texas, 1994. https://digital.library.unt.edu/ark:/67531/metadc277926/.
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Palladium catalyzed reactions of derivatives of 2,4-diiodophenol are explored. Coupling reactions with a series of terminal alkynes and formylation are found to be efficient and regioselective. Coupling with stananne reagents and alkenes do not work. The nature of the oxygen protecting group is critical. The phytotoxic natural product, Eutypine, is synthesized by using regioselective formylation and alkyne coupling. An approach to the plant antimicrobial compound Plicatin B is examined.
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Püntener, Kurt Andreas. "Chirale Palladium-Komplexe mit dreizähnigen Stickstoffliganden /." [S.l.] : [s.n.], 1994. http://e-collection.ethbib.ethz.ch/show?type=diss&nr=10888.
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Unterhalt, Holger. "Summenfrequenzerzeugungsspektroskopie an Platin- und Palladium-Modellkatalysatoren." [S.l.] : [s.n.], 2002. http://www.diss.fu-berlin.de/2002/123/index.html.
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Sävmarker, Jonas. "Palladium-Catalyzed Carbonylation and Arylation Reactions." Doctoral thesis, Uppsala universitet, Avdelningen för organisk farmaceutisk kemi, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-167720.
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Palladium-catalyzed reactions have found widespread use in contemporary organic chemistry due to their impressive range of functional group tolerance and high chemo- and regioselectivity. The pioneering contributions to the development of the Pd-catalyzed C-C bond forming cross-coupling reaction were rewarded with the Nobel Prize in Chemistry in 2010. Today, this is a rapidly growing field, and the development of novel methods, as well as the theoretical understanding of the various processes involved are of immense importance for continued progress in this field. The aim of the work presented in this thesis was to develop novel palladium(0)- and palladium(II)-catalyzed reactions. The work involved in achieving this aim led to the development of a Mo(CO)6-mediated carbonylative Stille cross coupling reaction for the preparation of various deoxybenzoins. The protocol utilized convenient gas-free conditions to facilitate the carbonylative coupling of benzyl bromides and chlorides with aryl and heteroaryl stannanes. Mo(CO)6-assisted conditions were then used in the development of a general protocol suitable for the aminocarbonylation of aryl triflates. Both electron-poor and electron-rich triflates were coupled with primary, secondary and aryl amines. In addition, DMAP was found to be a beneficial additive when using sterically hindered or poorly nucleophilic amines. An efficient and convenient method for the synthesis of styrenes from arylboranes was developed, employing the relatively inexpensive vinyl acetate as the ethene source under Pd(II)-catalyzed conditions. The reaction mechanism was studied using ESI-MS, and a plausible catalytic cycle was proposed. A method for the oxidative Heck reaction employing aryltrifluoroborates and aryl MIDA boronates was also developed. Electron-rich and electron-poor olefins were regioselectively arylated under microwave-assisted conditions. Various arylboron species were identified in an ongoing reaction using ESI-MS. Further investigations led to the development of a direct method for the synthesis of arylamidines from aryltrifluoroborates and cyanamides. Under Pd(II)-catalyzed conditions it was possible to insert the aryl into primary, secondary and tertiary cyanamides. Finally, a desulfitative method for the synthesis of aryl ketones was developed. A variety of aryl sulfinates were effectively inserted into alkyl- and aryl nitriles. The mechanism was further investigated using ESI-MS and a plausible catalytic cycle was proposed.
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Sullivan, Brian Thomas. "Spectroscopic ellipsometry of Palladium thin films." Thesis, University of British Columbia, 1987. http://hdl.handle.net/2429/27546.
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Spectroscopic ellipsometry is a nondestructive, ambient surface analysis technique for studying surfaces, interfaces and thin films. To take advantage of this method an automatic spectroscopic ellipsometer was designed and constructed for the microstructural characterization of thin films. This high precision instrument is capable of measuring in real-time the optical properties of bulk or thin film materials over the visible-UV region (1.5 - 6.0 eV). The microstructure of thin films can be determined from an effective medium theory analysis of the spectroellipsometric data to investigate how the film morphology evolves with varying preparation conditions and to determine the optimum deposition parameters.
In this thesis the pseudodielectric function of palladium films prepared by dc planar magnetron sputtering was measured while the substrate temperature, argon partial pressure and rf-induced substrate bias were varied independently during deposition. The film data are in excellent agreement with the effective medium theory of Sen, Scala, and Cohen, relevant for a random coated-particle microstructure where the grains are optically isolated from each other.
With increasing substrate temperature, the Pd volume fraction in the bulk was found to decrease slightly, while the rms microroughness of the film surface increased in magnitude. At 190° C, the rms microroughness was 80 ± 3 Awith the Pd volume fraction in the bulk region falling slightly to 97 ± 1% relative to the film deposited at 22° C.
For argon partial pressures below a transition pressure, Pt≃15 mTorr, the films consisted of densely packed grains, corresponding to the zone T in Thornton's structure zone model. Above this transition pressure, the films developed into a more voided columnar structure, characteristic of the zone 1 region. A microstructural analysis indicated a general trend towards increased porosity and microroughness of the films with higher argon pressures. The zone 1 region was best described optically by a random coated-particle microstructure and the electron microscopy confirmed that for thin films prepared at argon pressures higher than Pt, the grains became isolated by void boundaries. The optical data could not distinguish whether or not the films were 2- or 3-dimensionally isotropic.
With increasing rf-induced substrate biasing, the Pd film microstructure was modified in a manner similar to that obtained by varying the substrate temperature alone. Significant resputtering of the Pd films occurred, varying from 2 to 11 A/sec for bias voltages of -550 V to -1375 V, respectively. The measured deposition rate while bias sputtering was significantly higher than that expected upon the measured resputtering rate and several mechanisms were proposed to account for the enhancement in the deposition rate. The films were best characterized by a 2-dimensional isotropy which was supported by the columnar nature of the films observed by electron microscopy.
Finally, the dielectric function of the "best" palladium film is compared to optical constants of Pd previously reported in the literature for bulk and thin film specimens. While all the authors quote essentially the same values for the real part of the dielectric function, regardless of the preparation or measurement technique, the imaginary part differs up to a factor of two. Surface microroughness, bulk porosity and oxide layers are unable to account for the difference. A possible grain boundary scattering mechanism is suggested.Science, Faculty of
Physics and Astronomy, Department of
Graduate
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Clentsmith, Guy Kenneth Bruce. "Dinuclear palladium complexes with bridging hydrides." Thesis, University of British Columbia, 1991. http://hdl.handle.net/2429/29800.
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The palladium hydride dimer, [(dippp)Pd]₂(µ--H)₂, (2) (dippp = 1,3-bis(diisopropylphosphino)propane), was synthesized, and its interaction with lithium tetraethylborate examined. When the two compounds were mixed in stoichiometric amounts high yields of the adduct, [(dippp)Pd]₂(µ-H) ₂•LiBEt₄ (1) — previously isolated adventitiously by a co-worker — were obtained. Variable temperature ³¹P{¹H} NMR spectroscopy showed a condition of chemical equilibrium between 2 and 1, but the value of the equilibrium constant, Keq, could not be determined owing to its large magnitude. Extension of this chemistry to other sources of Li⁺ led to the isolation of the aluminate adduct, [(dippp)Pd]₂((µ-H)₂,•LiA1Et₄ (3). Likewise when NaBEt₄ was substituted an adduct formulated as [(dippp)Pd]₂(µ-H)₂•NaBEt₄ (4) was obtained.
The interaction of tetraethylborate salts with other transition-metals was also examined, with evidence of adduct formation for both [(dippp)Rh]₂(µ-H)₂ and [(dippp)Ni]₂(µ-H)₂ (6) with LiBEt₄. It was not possible to isolate these compounds as analytically pure samples. This general interaction is discussed in terms of metal basicity.
The reactivity of 2 towards organic donor species was also studied. Addition of excess donor results in the formation of tricoordinate Pd(0) species: (dippp)Pd(ɳ²-H₂C=CH₂) (5), (dippp)Pd(PPh₃) (7), and (dippp)Pd(DMAD) (8) (DMAD = dimethylacetylenedicarboxylate) were thus isolated. When a stoichiometric equivalent of donor was added to 2, no dimeric intermediates could be observed.Science, Faculty of
Chemistry, Department of
Graduate
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Robinson, I. K. "Computational studies of hydrogen in palladium." Thesis, University of Salford, 2015. http://usir.salford.ac.uk/45237/.
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A series of Monte-Carlo investigations on the Palladium Hydrogen system are presented. It is demonstrated that a simple long-range concentration-dependent attractive force reproduces the form of the pressure-composition isotherms well. Short range pairwise repulsive forces reproduce much of the hydrogen ordering seen within the lattice. A suitable scaling between the long and short range forces has been found which appears to reproduce both the isotherms and the short-range ordering to a reasonable degree. Programs have been written to generate virtual diffractograms in 1d and 2d in order to observe ordering in the simulations and inform those performing experimental diffraction studies. Studies have been performed of the isotope dependence of absorption taking into account the differing zero point energies of the three hydrogen isotopes.
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Farhad, Mohammad. "Studies on new trinuclear palladium compounds." Connect to full text, 2007. http://hdl.handle.net/2123/2477.
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Doctor of Philosophy(PhD)The present study deals with the synthesis and characterization of six tri-palladium complexes code named MH3, MH4, MH5, MH6, MH7 and MH8 that contained two planaramine ligands bound to the central or each of the terminal metal ions. The activity of the compounds against human cancer cell lines: A2780, A2780cisR and A2780ZD0473R, cell uptake, levels of DNA-binding and nature of interaction with salmon sperm and pBR322 plasmid DNA have also been determined. Whereas cisplatin binds with DNA forming mainly intrastrand GG adduct that causes local bending of a DNA strand, the tri-palladium complexes are expected to bind with DNA forming a number of long-range interstrand GG adducts that would cause a global change in DNA conformation. Among the designed complexes, MH6 that has two 2-hydroxypyridine ligands bound to each of the two terminal palladium ions is found to be most active. The compound also has the highest cell uptake and Pd-DNA binding levels. In contrast, MH8 which has two 4-hydroxypyridine ligands bound to each of the two terminal palladium ions is found to be least active. The results indicate that, as applied to the terminal metal centres, 2-hydroxypyridine would be more activating than 4-hydroxypyridine perhaps because of greater protection provided to the terminal centres from coming in contact with the solvent molecules. In contrast, when bound to the central metal centre, 4-hydroxypyridine appears to play a slightly greater activating role than 2-hydroxypyridine or 3-hydroxypyridine, suggesting that non-covalent interactions such as hydrogen bonding associated with the ligand rather than its steric effect may be a more important determinant of antitumour property. The results illustrate structure-activity relationships and suggest that the tri-palladium complex containing two 2-hydroxypyridine ligands bound to each of the three metal centres or the compound that contains two 2-hydroxypyridine ligands bound to each of the two terminal metal centres and two 4-hydroxypyridine ligands bound to the central metal centre, may be much more active than any of the designed complexes.
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Amandusson, Helena. "Hydrogen extraction with palladium based membranes /." Linköping : Univ, 2000. http://www.bibl.liu.se/liupubl/disp/disp2000/tek651s.htm.
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Du, Toit Zita. "Simulation of a palladium extraction circuit." Thesis, Stellenbosch : University of Stellenbosch, 2006. http://hdl.handle.net/10019/536.
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