Dissertations / Theses on the topic 'Phosphine'
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1
Phung, Quang Linh. "Synthèse de ligands chiraux de type phosphine-phosphite et phosphine-carbène N-hétérocyclique pour la catalyse asymétrique." Rouen, 2005. http://www.theses.fr/2005ROUES033.
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La catalyse organométallique est une méthode de choix pour la synthèse de composés chiraux. Afin d'atteindre une selectivité et efficacité élevées en catalyse asymétrique, plusieurs paramètres réactionnels doivent être optimisés, parmi lesquels le choix et la structure du ligand sont sans doute les points les plus importants. Nous avons développé deux familles de ligands bidentates de type phosphine-phosphite et phosphine-carbène N-hétérocyclique. Ces deux séries de ligands possèdent une caractéristique structurale commune, à savoir un centre asymétrique adjacent à la phosphine. Cette proximité du centre stéréogène et de l'atome de phosphore pourrait avoir un effet positif sur l'énantiodiscrimination. Les ligands phosphine-phosphites ont été testés en hydrogénation (ee jusqu'à 84%) et hydroformylation (pas d'induction asymétrique) asymétriques catalysées par le rhodium. Les ligands phosphine-carbènes N-hétérocycliques ont été testés en hydrogénation et hydrosilylation asymétriques catalysées à l'iridium (pas d'induction asymétrique), et avec des résultats prometteurs dans le couplage de Suzuki-MiyauraCatalytic asymmetric synthesis using organometallic reagents has become one of the most active areas of research in modern organic synthesis. To achieve the highest levels of reactivity and selectivity in catalytic enantioselective reactions, several reactions parameters must be optimized. Among them, the selection and design of the chiral ligand is perhaps the most crucial step. We have developed two families of bidentate ligands : phosphine-phosphite and phosphine N-heterocyclic carbene. These two series of ligands have a chiral center to the α-position next to the phosphine moiety. This stereogenic α-position could be of great importance since the phosphorus atom is directly associated with the transition metal in the asymmetric reaction. Phosphine-phosphite ligands were tested in the Rh-catayzed asymmetric hydrogenation (ee up to 84%) and hydroformylation (no asymmetric induction). Phosphine N-heterocyclic carbene ligands were tested in the Ir-catalyzed asymmetric hydrogenation and hydrosilylation (no asymmetric induction), and with promising results in the Suzuki-Miyaura cross-coupling reaction
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Deerenberg, Sirik. "Stereogenic phosphorus containing phosphine-phosphite ligands in asymmetric catalysis." [S.l. : Amsterdam : s.n.] ; Universiteit van Amsterdam [Host], 2000. http://dare.uva.nl/document/57171.
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Javierre, Guilhem. "Understand the inversion mechanism of P-stereogenic compound using kinetic studies and in silico modeling." Thesis, Ecole centrale de Marseille, 2018. http://www.theses.fr/2018ECDM0001/document.
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La thèse consiste en l'étude de la racémisation d'hydrogéno-phénylphosphinates d'alkyle, des molécules centrées sur un phosphore stéréogénique. Pour cela, nous avons synthétisé les composés d'intérêt puis étudié leur cinétique de racémisation en utilisant l'HPLC chirale et la RMN du phosphore. La première étude théorique (SMD//M06-2X/6-31++G**) sur l’énantiomérisation d’un phosphinate d’alkyle après une SN2 par un alcool a montré comme mécanisme le plus favorable une syn-addition de l’alcool sur la double liaison P=O du phosphinate à l’opposé du groupement alkoxy. Les études cinétiques d’inversion du phosphinate d’éthyle dans l’éthanol à reflux ont montré une barrière de 135 kJ.mol-1 en moyenne, en excellent accord avec ce modèle (136 kJ.mol-1). L’ajout de base lors de l’étude cinétique ont montré une accélération de l’inversion avec une barrière maximum mesurée à 121,5 kJ.mol-1 montrant un effet de catalyse basique. Les modèles cinétiques et théoriques réalisés à ce jour ont suggéré que la base activerait l’alcool pour faciliter son addition. Les premiers résultats sur l’influence du groupement alkyle ont montré une dépendance globale de l’inversion à la taille du groupement, mais certains modèles DFT, notamment avec l’adamantyle, n’étaient pas en accord avec cette hypothèseThis thesis is about the racemization of alkyl hydrogeno-phenylphosphinate, a molecule centered on a stereogenic phosphorus atom. We have synthetized compounds of interest, and studied their kinetic of racemization with chiral HPLC and phosphorus NMR. The first theoretical study (SMD//M06-2X/6-31++G**) about the enantiomerization of alkyl phosphinate after an SN2 with an alcohol have shown that the most favored mechanism was a syn-addition of the alcohol onto the double bond P=O on the opposite side of the alkoxy group. Kinetic studies with ethyl phosphinate in ethanol under reflux have shown an inversion barrier around 135 kJ.mol-1, in excellent agreement with this model (136 kJ.mol-1). The addition of a basic compound during kinetic measurements has shown a decreasing of the barrier to 121.5 kJ.mol-1, showing a catalytic effect. Kinetic and theoretical models have suggested that the mechanism would go through an activation of the alcohol by the basic compound which would facilitate its addition. The first tests about the nature of the alkyl group of phosphinate and alcohol have shown a general dependency of the barrier with the hindrance, but some DFT models, especially with adamantyl, have been in disagreement with this hypothesis
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Gonschorowsky, Miriam. "Beiträge zur Chemie hydrophiler Phosphane." [S.l.] : [s.n.], 2004. http://deposit.ddb.de/cgi-bin/dokserv?idn=973540788.
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Nickel, Thomas. "Neue Synthesen chiraler und polar funktionalisierter Phosphanliganden." [S.l. : s.n.], 2000. http://deposit.ddb.de/cgi-bin/dokserv?idn=963282336.
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Harrison, Mark Anthony. "EXPOSURE TO PHOSPHINE GAS DURING APPLICATION OF MAGNESIUM PHOSPHIDE IN STORED PRODUCT WAREHOUSES." VCU Scholars Compass, 1990. http://scholarscompass.vcu.edu/etd/4909.
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The use of phosphine gas requires that respiratory protection be used if exposures exceed the OSHA permissible exposure limit. As with other chemical exposures limits many of the references used to establish occupational health guidelines date back to the 1930’s and 1940’s. This is quite common and is the case with phosphine gas. Initial planning for fumigations involving magnesium phosphide requires that a hazard assessment be performed. Expected worker exposures based on previous monitoring or test data was not readily available. Many current practices and procedures for fumigations are based on recommendations from applicators who used the product in the 1950’s and 60’s. Unfortunately, many of the recommendations were based on personal opinion and experience rather than actual exposure monitoring data. Not until the 1980's were comprehensive applicator exposure assessments being conducted for different tasks involving magnesium phosphide. As a result, it is necessary to generate current applicator exposure data and compare the data to current occupational exposure limits for phosphine gas.
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Roscoe, Jane Caroline. "Unsymmetrical tridentate phosphine ligands." Thesis, University of Central Lancashire, 1991. http://clok.uclan.ac.uk/20127/.
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A general synthetic route, via phosphonium salts and phosphine oxides has been developed for the preparation of unsymmetrical triphosphine ligands, which necessarily contain one central chiral phosphorus atom. The ttparent" tridentate phosphine is (2- diphenylphosphinoethyl)(3-diphenylphosphinopropyl) phenylphosphine, Ph2P(CH2)3PPh(CH2)2PPh2, "eptp". Other tridentates were prepared by varying the substituents at one phosphorus atom to form the analogous ligands with a general formula of R2P(CH2)3PPh(CH2)2PPh2 where R=p-FC6H4, p-C1C6H4, o-CH30C6H4. The ligands were found to complex readily with nickel(Il) and palladium(ll) to form air-stable complexes containing square planar species such as [NiI(eptp)]+ in solution. Complexes were isolated using C104, PF6- and 1 as counterions, and were characterised by elemental analysis, magnetic and conductance measurements, infrared spectroscopy, and especially by 31 P nmr spectroscopy where the three non-equivalent phosphorus nuclei, all coupled to one another, provided a wealth of useful data. Crystals were grown for a single-crystal X-ray crystallographic study of the Ni12 complex of eptp, which showed one weakly bonded iodo ligand at the apex of a square pyramid. This is the site at which a substrate molecule would be expected to coordinate in any asymmetric homogeneous catalytic application; the other side of the square plane was sterically crowded. The unit cell contained four molecules, two of each enantiomer. The nickel(II)-triphosphine complexes were screened for catalytic activity in the hydrogenation of alkenes. In this investigation they were all found to be inactive for hydrogenation at ambient conditions. However addition of a little NaBH4 produced colourless solutions, presumably nickel(0) complexes, which in air were found to be excellent oxidation catalysts, rapidly oxidising added phosphines to phosphine oxides. The phosphine oxide intermediate in the tridentate phosphine ligand synthesis, Ph2P(0)(CH2)3P(0)Ph(CH2)2PPh2, teptp02, provided an attractive stage at which to investigate resolution of the two enantiomers, since the final trichlorosilane reduction stage of the phosphine oxides to phosphines is known to be stereospecific. 31P nmr studies showed strong chiral recognition between eptp02 and (+)-camphorsulphonic acid in CDCI3. The novel mixed phosphine/phosphine oxide ligand eptp02 was found to coordinate exclusively via phosphorus to palladium(Il) in [PdC12(eptpO2)21 or via the phosphine oxide groups to lanthanum(lII). It would also coordinate simultaneously to both, and so is ideally suited to the preparation of very unusual heterobinuclear complexes containing one oxophilic f-block metal ion (e.g. La 3 ) and one 'soft' d-block metal ion (e.g. Pd2+). Such complexes presumably contain macrocyclic rings involving both types of metal ion. Various other routes to unsymmetrical tridentate ligands were investigated which involved some unusual mixed bidentate ligands. A new route to bisphosphine monoxides, Ph2P(CH2)P(0)Ph2, has been developed in this programme. These monoxides provided a simple route to new tn- and tetra- phosphine oxides such as eptp03 and the "2,3,2"-tetraoxide , Ph2P(0)(CH2)2P(0)Ph(CH2)3P(0)Ph(CH2)2P(0)Ph2. In collaboration with The University of Barcelona, (Campus of Tarragona), the bisphosphine monoxides with -(CH2)2- and -(CH2)4- backbones were converted to ligands containing both a phosphine sulphide and a phosphine oxide group e.g. Ph2P(S)(CH2)2P(0)Ph2. This ligand and the bisphosphine monoxide, were found to coordinate to tin(II) chloride through the phosphine oxide only. Whereas various alkyl and aryl substituents at phosphorus have been extensively investigated in polyphosphine ligands by previous workers, the pyridyl substituent has not been used in this way. This would be an interesting substituent as it is sterically similar to phenyl but electronically quite different. New routes to a pyridyl substituent at phosphorus were investigated, producing the previously unknown pyridyltriphenyiphosphonium salt [PPh3(2-py)]Br and the ligand 6-bromo-2(diphenylphosphino)pyridine. When hydrolysed phosphonium salts containing a pyridyl group were found to lose the pyridyl group in preference to phenyl, so elaboration to di- and tri-phosphines was not possible.
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Plancq, Sabine. "Heteronuclear carbonyl phosphine complexes." Thesis, Heriot-Watt University, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.335276.
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Hutton, Gordon Eric. "Stereocontrol with phosphine oxides." Thesis, University of Cambridge, 1994. https://www.repository.cam.ac.uk/handle/1810/273009.
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Passays, Johan. "Nouveaux ligands mixtes de type phosphore / carbène N-hétérocyclique : synthèse et applications en catalyse asymétrique." Thesis, Rouen, INSA, 2011. http://www.theses.fr/2011ISAM0008.
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Une méthode simple et efficace a été développée pour la préparation de ligands bifonctionnels associant les motifs phosphine ou phosphite d'une part, et carbène Nhétérocyclique(NHC) ou imidazolium d'autre part. Dans un premier temps, une série de ligands diphénylphosphine-carbène chiraux portant un centre stéréogène en a de la phosphinea été développée à partir b-hydroxyesters. Une famille de ligands a ainsi été développée afin d'évaluer l'influence de l'encombrement stérique de différents groupements alkyles en a de la phosphine et de la nature des groupements aromatiques portés sur l'imidazole sur leur activité catalytique. L’étude s’est ensuite étendue à la synthèse de ligands de type dialkylphosphine carbène et phosphite-carbène. Ces différents ligands ont été complexés avec des métaux tels que l’iridium ou le rhodium de manière à en étudier l’activité en hydrogénation asymétriqueA straightforward method for the preparation of new bidentate ligands containing aphosphine or a phosphite and a carbene function was developed. Different phosphorus-imidazolium compounds were prepared according to this method. First, diphenylphosphine-NHC ligands featuring a stereogenic center a to the phosphine were synthesized from b-hydroxyesters. This strategy was then extended to the preparation of phosphite-imidazoliumand dialkylphosphine-imidazolium compounds. Complexation of these phosphorus-NHCligands with different metals like Ir or Rh was performed in order to study there catalytic properties in asymmetric hydrogenation
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Alcaraz, Gilles. "Espèces déficientes en électrons et cycles tendus alpha-phosphorés." Toulouse 3, 1995. http://www.theses.fr/1995TOU30126.
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Les -phosphinocarbenes et les -phosphinonitrenes sont des entites presentant un fort caractere nucleophile. En presence de boranes, la formation d'adduits de type carbene-acide de lewis et nitrene-acide de lewis a ete demontree sans ambiguite. La caracterisation par spectroscopie rmn d'un adduit phosphinocarbene-borane a pu etre realisee. Dans le second chapitre, une methode de synthese originale de phosphino-2h-azirines par cycloaddition (1+2) d'un phosphinosilylcarbene sur des nitriles est presentee. Les phosphino-2h-azirines se comportent soit comme des phosphines vraies soit comme des dipoles-1,4. Elles peuvent egalement par reaction d'extension de cycle conduirent a des 1,2#5-azaphosphetes. Dans le troisieme chapitre, la reactivite de la bromophenyldiazirine en presence de phosphines a ete etudiee. D'un point de vue mecanistique nous avons demontre que la premiere etape de l'attaque met en jeu une isodiazirine transitoire. D'un point de vue synthetique, le comportement de la bromophenyldiazirine comme pourvoyeur de fragment nc(ph)n+ a ete mis a profit pour engendrer toute une gamme d'especes polyphosphorees cationiques acycliques, cycliques et macrocycliques. En presence de stannylphosphine, l'obtention d'un heterocycle phosphore (le 1,3,2#5-diazaphosphete) demontre clairement l'enorme potentiel de la reaction mise en jeu
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李慧敏 and Huai-min Li. "Photochemical studies of binuclear platinum and rhodium complexes withbridging isocyanide, phosphite and phosphine ligands." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 1989. http://hub.hku.hk/bib/B31231603.
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Swor, Charles D. (Charles David) 1982. "Synthesis, coordination chemistry, and reactivity of functionalized phosphines: Toward water-soluble macrocyclic phosphine complexes." Thesis, University of Oregon, 2011. http://hdl.handle.net/1794/11264.
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xx, 290 p. : ill. (some col.)Macrocyclic phosphine compounds have long been sought as ligands for transition metal complexes because of their strong binding properties. Despite considerable effort in this field, no general methods for synthesizing phosphine macrocycles or their complexes have been developed. This dissertation describes attempts to synthesize an iron complex with a water-soluble macrocyclic tetraphosphine ligand for use in separating nitrogen from natural gas. Chapter I reviews previous syntheses of macrocyclic phosphine ligands and their complexes, focusing on ligand synthesis, coordination chemistry, and demetallation of the complexes. Chapter II reports on the synthesis of water-soluble secondary bidentate phosphine ligands, their coordination chemistry with iron(II), and attempts to use these complexes as templates for forming a macrocyclic iron-phosphine complex by reactions with carbon electrophiles. Over the course of treating these iron complexes with various carbon electrophiles, an interesting reaction between bromomaleic anhydride and proton sponge was discovered. Chapter III explores the product, 4-maleicanhydrido-1,8-bis-(dimethylamino)naphthalene (MAPS). Due to its conjugated donor-acceptor network, which is disrupted upon protonation, MAPS acts as a colorimetric version of a proton sponge. The attachment of MAPS to amine-functionalized solid supports, forming solid-supported proton sponge reagents, is also described. Chapter IV discusses the synthesis of an iron(II) complex of the water-soluble phosphine 1,2-bis(di(hydroxymethyl)phosphino)ethane (DHMPE). Although unbound hydroxymethylphosphines commonly react with NH-functional amines via the phosphorus Mannich reaction, this and other complexes of DHMPE do not undergo this reaction. Further investigation with hydroxymethylphosphine-boranes suggests that the currently-accepted mechanism of the phosphorus Mannich reaction is incorrect, and an alternate mechanism is proposed. Chapter V discusses the synthesis and functionalization of copper(I) complexes of water-soluble phosphines. Unlike the complexes described in Chapter I, these complexes readily react with α,ω-dihalides or di(acyl chloride)s, forming complexes whose mass spectra correspond to those with macrocyclic phosphine ligands. Unlike most macrocyclic tetraphosphine complexes, these complexes can be demetallated by treatment with sulfide. Finally, a new synthesis of water-soluble macrocycles, based on lessons learned during the course of these investigations, is proposed. This dissertation includes previously published and unpublished co-authored material.
Committee in charge: Dr. Michael M. Haley, Chairperson; Dr. David R. Tyler, Advisor; Dr. Darren W. Johnson, Member; Dr. Shih-Yuan Liu, Member; Dr. Mark H. Reed, Outside Member
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Devillard, Marc. "Dérivés ambiphiles : chimie de coordination d'un phosphine-alane, synthèse et réactivité de phosphine-boréniums." Toulouse 3, 2014. http://thesesups.ups-tlse.fr/2647/.
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Ce travail porte sur la chimie des dérivés ambiphiles combinant une base et un acide de Lewis de type PE (E = B, Al). Le premier chapitre aborde l'étude d'adduits phosphine-boranes et phosphine-boréniums dans lesquels le phosphore et le bore sont en positions peri d'un noyau naphthalène. Dans une première partie, l'influence du squelette carboné ainsi que des substituants portés par le bore sur l'interaction donneur-accepteur PB au sein d'une famille de phosphine-boranes a été étudiée par des méthodes expérimentales et théoriques. Dans une deuxième partie, ce système a été étendu à la préparation de boréniums stabilisés intramoléculairement par la phosphine. L'acidité de ces espèces cationiques du bore a été estimée par différentes méthodes expérimentales et leur réactivité vis-à-vis de petites molécules a été étudiée. Le deuxième chapitre porte sur l'étude en coordination d'un ligand monophosphine-alane à espaceur Csp2 vis-à-vis des métaux chlorures des groupes 9 à 11. L'influence de la géométrie du fragment métallique et de la nature des co-ligands sur le mode de coordination du ligand ambiphile ont été étudiées. Une attention particulière a été portée sur la chimie de coordination à l'or(I) qui a permis d'accéder à un complexe actif en cycloisomérisation catalytique. Le troisième chapitre explore plus avant la chimie de coordination du ligand monophosphine-alane et se concentre sur le comportement de type Z d'un tel ligand. La capacité de l'aluminium à accepter un transfert de densité électronique de la part de l'or(I) et du platine(0) a été étudiée par des méthodes expérimentales et théoriques. Dans le cas des complexes d'or, la nature du co-ligand a été variée et son influence sur la force de l'interaction a été étudiée. Finalement, le complexe de platine(0) a fait l'objet d'une étude en réactivité vis-à-vis du dihydrogèneThis work deals with the chemistry of ambiphilic derivatives that combine a Lewis base and a Lewis acid of general formula PE (E = B, Al). The first chapter deals with the study of phosphine-borane and phosphine-borenium adducts in peri position on a naphthalene backbone. First, the influence of the naphthyl backbone and the substituents at boron on the PB donor-acceptor interaction was studied with different analytical methods. This system was then applied to the prepration of boreniums stabilized intramolecularly by the phosphorus. The Lewis acidity as well as the reactivity of such species toward small molecules were studied. The second chapter focuses on the coordination chemistry of a phosphine-alane ambiphilic ligand containing a Csp2 linker toward M-Cl bonds in transition metal fragments of groups 9 to 11. The gold chemistry has been studied particularly in detail as well as the capability of the resulting complexes to promote cycloisomerisation processes catalytically. The third chapter further explores the coordination chemistry of the phosphine-alane ligand and focuses on its ability to behave as a Z-type ligand. The propensity of the aluminum atom to accept electron density from the isoelectronic gold(I) and platinum(0) has been assessed by experimental and computational means. The influence of the organic co-ligand on the strength of the interaction was also investigated. Finally, the reactivity of the platinum complex toward dihydrogen has been studied
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Prabagar, Jasotha. "Synthesis of bulky phosphine ligands." Thesis, University of Oxford, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.437012.
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Lavender, Mark Harley. "Phosphine stabilised di-iron complexes." Thesis, University College London (University of London), 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.283749.
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Wells, F. J. "Tertiary phosphine complexes of vanadium." Thesis, Imperial College London, 1987. http://hdl.handle.net/10044/1/46906.
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Dai, Xuedong 1970. "Synthesis of novel phosphine ligands." Thesis, Massachusetts Institute of Technology, 1995. http://hdl.handle.net/1721.1/36078.
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Tyzack, Charles Richard. "Stereocontrolled synthesis using phosphine oxides." Thesis, University of Cambridge, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.620349.
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Javierre, Guilhem. "Understand the inversion mechanism of P-stereogenic compound using kinetic studies and in silico modeling." Electronic Thesis or Diss., Ecole centrale de Marseille, 2018. http://www.theses.fr/2018ECDM0001.
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La thèse consiste en l'étude de la racémisation d'hydrogéno-phénylphosphinates d'alkyle, des molécules centrées sur un phosphore stéréogénique. Pour cela, nous avons synthétisé les composés d'intérêt puis étudié leur cinétique de racémisation en utilisant l'HPLC chirale et la RMN du phosphore. La première étude théorique (SMD//M06-2X/6-31++G**) sur l’énantiomérisation d’un phosphinate d’alkyle après une SN2 par un alcool a montré comme mécanisme le plus favorable une syn-addition de l’alcool sur la double liaison P=O du phosphinate à l’opposé du groupement alkoxy. Les études cinétiques d’inversion du phosphinate d’éthyle dans l’éthanol à reflux ont montré une barrière de 135 kJ.mol-1 en moyenne, en excellent accord avec ce modèle (136 kJ.mol-1). L’ajout de base lors de l’étude cinétique ont montré une accélération de l’inversion avec une barrière maximum mesurée à 121,5 kJ.mol-1 montrant un effet de catalyse basique. Les modèles cinétiques et théoriques réalisés à ce jour ont suggéré que la base activerait l’alcool pour faciliter son addition. Les premiers résultats sur l’influence du groupement alkyle ont montré une dépendance globale de l’inversion à la taille du groupement, mais certains modèles DFT, notamment avec l’adamantyle, n’étaient pas en accord avec cette hypothèseThis thesis is about the racemization of alkyl hydrogeno-phenylphosphinate, a molecule centered on a stereogenic phosphorus atom. We have synthetized compounds of interest, and studied their kinetic of racemization with chiral HPLC and phosphorus NMR. The first theoretical study (SMD//M06-2X/6-31++G**) about the enantiomerization of alkyl phosphinate after an SN2 with an alcohol have shown that the most favored mechanism was a syn-addition of the alcohol onto the double bond P=O on the opposite side of the alkoxy group. Kinetic studies with ethyl phosphinate in ethanol under reflux have shown an inversion barrier around 135 kJ.mol-1, in excellent agreement with this model (136 kJ.mol-1). The addition of a basic compound during kinetic measurements has shown a decreasing of the barrier to 121.5 kJ.mol-1, showing a catalytic effect. Kinetic and theoretical models have suggested that the mechanism would go through an activation of the alcohol by the basic compound which would facilitate its addition. The first tests about the nature of the alkyl group of phosphinate and alcohol have shown a general dependency of the barrier with the hindrance, but some DFT models, especially with adamantyl, have been in disagreement with this hypothesis
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Horiuti, Toshihide. "Studies on Enantioselective Addition to C=C Bonds Catalyzed by Transition Metal-Phosphine-Phosphite Complexes." Kyoto University, 1997. http://hdl.handle.net/2433/202317.
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Li, Huai-min. "Photochemical studies of binuclear platinum and rhodium complexes with bridging isocyanide, phosphite and phosphine ligands /." [Hong Kong] : University of Hong Kong, 1989. http://sunzi.lib.hku.hk/hkuto/record.jsp?B12428541.
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Nijland, Aike. "On Tris(hydroxymethyl)phosphine-mimicking Non symmetrical Bis(phosphines) in Coordination Chemistry, Catalysis, and Cytotoxity." Thesis, Université Paris-Saclay (ComUE), 2017. http://www.theses.fr/2017SACLX003.
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La bis(phosphine) non symétrique Ph2P(CH2)2P(CH2OH)2 a été conçue et synthétisée afin d’imiter la tris(hydroxyméthyl)phosphine, une structure intéressante pouvant être utilisée en catalyse avec des métaux de transition car elle peut changer la sphère de coordination de ceux-ci. Si l’hydroxyméthylphosphine est liée à une donneur de diphénylphosphine possédant un pont éthane-1,2-diyl, ce dernier devrait permettre d’augmenter la stabilité du complexe à travers son effet chélatant, pour fournir un complexe mieux défini. Afin de comprendre l’origine de phénomènes indésirables provenant d’hydroxy-méthylphosphines, nous avons également synthétisé leurs analogues munis des fonctions bis(méthoxyméthyl)phosphine et aminométhylphosphines ainsi que les 2,6-dihydroxy-phosphinanes. Ces bis(phosphines) ont été utilisées pour former des complexes avec différents métaux de transition (Co(II), Ni(II), Ru(II), Rh(I), Pd(II), et Pt(II)). Il est à noter que des effets de liaisons hydrogènes ont sur la stéréochimie ont été observés, et que des arguments provenant de la littérature concernant la coordination d’hydroxyméthylphosphines ont été réfutés. Certains complexes possèdent également une activité cytotoxique importante envers des cellules cancéreuses humaines. Les ligands ont également été employés avec succès en catalyse, avec du rhodium pour réaliser des hydrogénations d’enamides et avec des métaux du groupe 10 pour effectuer l’hydro-phosphination du formol par PH3The non-symmetrical bis(phosphine) Ph2P(CH2)2¬P(CH2OH)2 was designed and synthesized as a mimic of tris(hydroxymethyl)phoshine; this structure is appealing for use in transition metal catalysis but is known to show unpredictable reactivity in transition metal coordination spheres. Having a hydroxymethylphosphine connected to a conventional diphenylphosphine donor with an ethane-1,2-diyl bridge should provide increased stability through the chelate effect and thus better-defined coordination complexes. To obtain data concerning the origin of the undesired acitivity of hydroxymethylphosphines, we also synthesized aprotic bis(methoxy) and aminomethylphosphine and cyclic dihydroxyphosphinane analogues of the non-symmetrical bis(phosphine). These bis(phosphines) have been used to form coordination complexes with a number of transition metals (Co(II), Ni(II), Ru(II), Rh(I), Pd(II), and Pt(II)). Significant hydrogen bonding influence on stereochemistry were observed and some arguments regarding hydroxymethylphosphine coordination in the literature were refuted. A selection of the complexes has also been shown to possess significant cytotoxic activity against a human cancer cell line. The ligands have also been employed successfully as ligands in two catalytic systems, viz. RhI catalysed hydrogenation and group 10 metal catalysed hydrophosphination of formaldehyde
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Dallanegra, Romaeo. "Cationic rhodium complexes with chelating phosphine and phosphine alkene ligands. Application in dehydrogenation and dehydrocoupling reactions." Thesis, University of Oxford, 2011. http://ora.ox.ac.uk/objects/uuid:c6841db3-aadf-428f-bd4e-a16e9eaa3511.
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A series of cationic Rh(I) diphosphine and phosphine-alkene complexes have been isolated and fully characterised. The reactivity of these species towards hydrogenation, dehydrogenation and dehydrocoupling reactions has been investigated. The use of potentially hemilabile ligands DPEphos and XANTphos in the intramolecular dehydrogenation chemistry of tricyclopentylphosphine is reported. The comparison in reactivity of these isolated diphosphine phosphine-alkene complexes towards hydrogenation and with acetonitrile is discussed along with their ability to dehydrocouple secondary silane, Ph₂SiH₂, and amine-borane H₃B·NMe₂H. The acceptorless dehydrogenation of a tethered cyclopentane with cationic Rh(I) diphosphine complexes has also been extended to include thioethers. Isolated cationic Rh(I) phosphine-alkene complexes with labile fluorobenzene ligands are found to act as a source of the reactive 12-electron [Rh{PR₂(ƞ²-C₅H₇)}]+ (R = cyclopentyl (Cyp)/ iPr) fragment in solution and can coordinate two amine-borane ligands (either H₃B·NMe₃, H₃B·NMe₂H or H₃B·NMeH₂) in a novel and unique bis-σ-binding mode. The catalytic activity of some of these isolated complexes in the dehydrocoupling of H₃B·NMe₂H and H₃B·NMeH₂ has been determined. With a view to further understanding the mechanism of catalytic transition metal assisted amine-borane dehydrogenation and dehydrocoupling, known B-N intermediates H₃B·NMe₂BH₂·NMe₂H and [H₂B·NMeH]₃ were also coordinated to the [Rh{PCyp₂(ƞ²-C₅H₇)}]+ fragment and investigated with regard to their role in the catalytic cycle. Structure activity relationships determined from stoichiometric reactions of cationic Rh(I) diphosphine fluorobenzene complexes with amine-boranes enabled the design of a highly efficient homogeneous catalyst capable of dehydrogenating H₃B·NMe₂H to [H₂BNMe₂]₂ at 0.2 mol% loading in 30 minutes at 298 K. Rapid dehydrogenation and dehydrocoupling of H₃B·NMeH₂ to form high molecular weight poly(N-methylaminoborane) with a low PDI has also been achieved. Investigations using model aminoborane H₂B=NiPr₂ and intermediate B-N species H₃B·NMe₂BH₂·NMe₂H and [H₂B·NMeH]₃ has helped establish an overall mechanistic rationale for this process.
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Oba, Boussou Gabriel. "Phosphine-boranes. Cyclométallation stéréosélective et résolution dynamique." Toulouse 3, 2000. http://www.theses.fr/2000TOU30148.
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Ce travail, effectue au laboratoire d'heterochimie fondamentale et appliquee, s'est donne comme objectif la synthese de nouvelles phosphine-boranes originales obtenues a partir de la reaction de cyclozirconation. Dans le chapitre i, une mise au point bibliographique sur les phosphine-boranes comportant plus de 150 references, traite de la nature de la liaison p-b, de leurs parametres physico-chimiques, de leur stabilite et des proprietes chimiques qui en decoulent. Dans la chapitre ii, l'etude de la reaction de cyclozirconation de derives diallyliques et tetraallyliques comportant un heteroelement a permis de preparer des heterocycles fonctionnalises dans des configurations differentes. En effet, en modifiant les substituants portes par l'heteroelement (si, ge), nous avons pu obtenir soit des modeles en configuration cis, soit des modeles en configuration trans. La configuration trans confere a ces systemes di et tetrafonctionnalises une chiralite (c 2 symetrique). Dans le chapitre iii, l'etude de la cyclometallation a ete etendue aux systemes diynes ou enynes. La necessite de substituer la partie terminale de l'insature acetylenique provoque des encombrements steriques qui ne favorisent pas toujours la cyclometallation (en particulier dans les essais de synthese de phospholes, boroles). Dans le chapitre iv, nous avons montre que la reaction de cyclozirconation pouvait etre conduite a partir de la phenyldiallylphosphine-borane. De nouveaux phospholanes, de nouvelles di et tetraphosphine-boranes ont pu etre ainsi synthetises. Dans le chapitre v, des phosphines et polyphosphines scalemiques ont ete preparees. La methode utilisee est basee sur l'induction importante apportee par une diamine chirale, la (-) sparteine, sur les phosphures de lithium configurationnellement labiles. Cette resolution dynamique a permis de preparer des phosphines p stereogeniques avec des exces enantiomeriques eleves.
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Pope, Simon Johnathan Albert. "Syntheses and studies on transition metal complexes involving phosphine ligands towards the syntheses of macrocyclic phosphines." Thesis, University of Southampton, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.302349.
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Laitinen, R. (Riitta). "New heterodonor phosphine and bipyridine ligands." Doctoral thesis, University of Oulu, 1999. http://urn.fi/urn:isbn:9514252292.
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Abstract
Twenty-seven phosphine and six bipyridine ligands were synthesised and characterized. Additionally, a new route to the family of phosphine ligands via o-thioanisyldichlorophosphine was found. The phosphine ligands contain thiomethylphenyl, methoxyphenyl, dimethylaminophenyl, pyridyl, naphthyl and anthracenyl groups, and the bipyridine ligands thiomorpholine and piperidine groups. Metal complexes of 3-pyridyldiphenylphosphine, 6,6'-bis(methylthiomorpholine)-2,2'-bipyridine and 4,4'-dimethyl-6,6'-bis(methylthiomorpholine)-2,2'-bipyridine were prepared.
Ligands and complexes were characterized by 1H-, 13C-, 31P- and two-dimensional HSQC-NMR spectroscopy, and crystal structures were determined for the ligands and two of the metal complexes. Tertiary phosphine ligands were prepared for catalytic purposes and tested in hydroformylation reaction at the Helsinki University of Technology and the University of Joensuu. Bipyridine ligands were designed for bimetallic coordination.
The phosphine ligands cover a wide range of electronic and steric properties. The spectroscopic parameters and crystal structures were studied with the purpose of charting trends in the basicities and steric effects of the ligands.
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Shepperson, Ian. "Phosphine ligands for fluorous biphasic catalysis." Thesis, Keele University, 2002. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.288436.
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Caldas, Hugo de Sousa Machado Feliciano. "Phosphine ligands for fluorous biphase catalysis." Thesis, Keele University, 2003. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.288440.
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Harmat, Nicholas J. S. "Chiral phosphine oxides in asymmetric induction." Thesis, University of Cambridge, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.317929.
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Armstrong, S. K. "Homoallylic amine synthesis using phosphine oxides." Thesis, University of Cambridge, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.596156.
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This thesis will describe the development of a new route to homoallylic amines 9, in four steps from alcohols 1, or acetals 2, which may themselves have to be synthesised. The synthesis is stereoselective, and generates E-9 and Z-9 quite separately, thereby avoiding the sometimes difficult separation of these isomers. Alkenes 3, readily available from alcohols 1 or acetals 2, undergo regio- and stereo-selective 1,3-dipolar cycloadditions with nitrile oxides 4 or nitrones 6. The resulting heterocycles 5 and 7 are reductively cleaved to give β-hydroxy-δ-aminoalkyldiphenylphosphine oxides 8. These alcohols undergo Horner-Emmons-type elimination of sodium diphenylphosphinite to give homallylic amines 9, stereospecifically. Isoxazolines 5, resulting from nitrile oxide cycloadditions, undergo stereoselective reduction, and give rise to primary amines 9, R3 = H. Isoxazolines 7, resulting from nitrone cycloadditions, give rise to secondary amines 9, R3 = alkyl or aryl. When the alkoxy substituted alkenes 3, R1 = OR are used, protected enol ethers 9, R1 = OR, R3 = Ac are the final products. The vital cycloaddition and reduction steps are both high yielding, although the elimination is often less so.
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Cartwright, Jonathan. "Organometallic chemistry of ruthenium phosphine complexes." Thesis, University of Warwick, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.307976.
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Norman, Timothy. "Imido and phosphine bridged organometallic complexes." Thesis, University College London (University of London), 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.243522.
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Morton, David Alexander Vodden. "Structural studies of metal phosphine complexes." Thesis, University of Bristol, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.303770.
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Armstrong, Susan Katherine. "Phosphine oxides in homoallyic amine synthesis." Thesis, University of Cambridge, 1991. https://www.repository.cam.ac.uk/handle/1810/272612.
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Herd, Oliver. "Neue Synthesen wasserlöslicher und axialchiraler Phosphanliganden." [S.l. : s.n.], 1999. http://deposit.ddb.de/cgi-bin/dokserv?idn=95704965X.
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Kühnel, Michael. "Neue Synthesewege zur Darstellung wasserlöslicher sulfonierter Phosphane." [S.l. : s.n.], 2002. http://deposit.ddb.de/cgi-bin/dokserv?idn=965427692.
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Pfletschinger, Andreas. "Neue temperaturschaltbare Phasentransferliganden für Palladium-katalysierte C-C-Kreuzkupplungen Konzept, Darstellung und grundlegende energetische Evaluation /." [S.l. : s.n.], 2002. http://deposit.ddb.de/cgi-bin/dokserv?idn=966001826.
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Thösen, Christoph. "Zur Synthese chiraler, zweizähniger Bis(trifluormethyl)phosphan-Liganden." [S.l. : s.n.], 2003. http://deposit.ddb.de/cgi-bin/dokserv?idn=968749895.
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Wei, Muh-Mei. "Nouveaux ligands phosphine chiraux pour l'hydrogénation asymétrique." Toulouse 3, 2013. http://thesesups.ups-tlse.fr/2240/.
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Parmi les réactions catalytiques asymétriques, l'hydrogénation occupe une place particulière. Les ligands phosphine chiraux ont un rôle important pour l'hydrogénation. Ce projet est consacré aux nouveaux ligands ferrocéniques pour l'hydrogénation asymétrique. La première partie, les nouveaux ligands {1,2-(TosNRCH2)(PPh2)C5H3}FeCp (R = H, Me) ont été entièrement synthétisés et caractérisés. Les complexes avec les précurseurs [Ru(p-cymene)Cl2]2, [RhCp*Cl2]2, [IrCp*Cl2]2, [Rh(COD)Cl]2 and [Ir(COD)Cl]2 ont été isolés et caractérisés. Une liaison N-H···Cl intramoléculaire a été étudiée par RMN à température variable et par des calculs DFT. L'addition de triéthylamine aux complexes précédent permet de former des ligands amidophosphine ferrocèniques coordinés de façon bidendate (κ2:P,N). Ces complexes ont ensuite été utilisés en catalyse d'hydrogénation. L'hydrogénation de l'arène a été observée en présence des complexes du RhI. L'analyse de TEM a montré la présence de nanoparticules métalliques de rhodium. La deuxième partie, un nouveaux ligands P,S ferrocènique, {1,2-(BrC6H4SCH2)(PPh2)C5H3}FeCp a été synthétisé et entièrement caractérisé pour le greffer dans des materiaux mésoporeux. La dernière partie, la coordination du ligand bis(triazol)diphosphine, de structure de symétrie C2 avec [Ir(COD)Cl]2, [PtCl2(PhCN)2] and [PdBr2(CH3CN)2] a été étudiée. Les complexes ont été isolés et entièrement caractérisés. La coordination de [Ir(COD)Cl]2 a été étudiée pour différents ratio P/Ir. Des activités excellentes ont été observées pour l'hydrogénation d'imine par ces complexes d'iridiumAsymmetric hydrogenation has advanced the field of asymmetric catalytic technology. Chiral phosphine based ligands have played a significant role for asymmetric hydrogenation. The first part of the thesis is devoted to the synthesis and characterization of new P,N ferrocenyl ligands {1,2-(TosNRCH2)(PPh2)C5H3}FeCp (R = H, Me) and their coordination chemistry with [Ru(p-cymene)Cl2]2, [RhCp*Cl2]2, [IrCp*Cl2]2, [Rh(COD)Cl]2 and [Ir(COD)Cl]2. Intra and inter molecular N-H···Cl bonds were investigated by variable temperature NMR and DFT calculations. Addition of triethylamine to the complexes with R = H allows removing the tosylamide acidic hydrogen atom giving rise to a ferrocenyl amidophosphine ligand coordinated in a bidendate fashion (ê2:P,N). Several complexes were assessed as precatalysts in the hydrogenation and transfer hydrogenation of acetophenone. Heterogeneous hydrogenation catalysis of the arene was observed in the presence of the RhI complex. The TEM and high resolution TEM showed the formation of metallic nanoparticles. In the second part, new P,S ferrocene-based {1,2-(BrC6H4SCH2)(PPh2)C5H3}FeCp ligands have been successfully synthesized and characterized in view of the catalysts anchored on mesoporous materials. In the final part, new complexes of a C2-symmetric bistriazolyl diphosphine coordinated to [Ir(COD)Cl]2, [PtCl2(PhCN)2] and [PdBr2(CH3CN)2] have been synthesized and characterized. The coordination chemistry with [Ir(COD)Cl]2 has been studied as a function of the P/Ir ratio. Hydrogenation and transfer hydrogenation processes catalyzed by these Ir complexes have been investigated, with excellent activities found for the hydrogenation of imines
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Bontemps, S. "Ligands ambiphiles phosphine-borane : synthèse et coordination." Phd thesis, Université Paul Sabatier - Toulouse III, 2006. http://tel.archives-ouvertes.fr/tel-00192021.
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Dans le premier chapitre, une étude bibliographique présente les rôles joués par les acides de Lewis du groupe 13, principalement du bore, en chimie organométallique. Même si dans ce domaine, ils sont principalement utilisés comme co-adduit, de rares exemples montrent que placés au sein d'un complexe métallique, ils peuvent (a) réaliser l'activation intramoléculaire d'une liaison M-X, (b) servir de point d'ancrage pour approcher un substrat riche en électrons du centre réactif et (c) interagir directement avec le métal lui-même.Dans le second chapitre, la synthèse et l'étude de la structure adoptée par les ligands ambiphiles sont discutées. Les facteurs régissant les préférences structurales des composés mono, di et triphosphine-borane sont étudiés.
Dans le troisième chapitre, l'étude de la coordination de composés ambiphiles monophosphine-borane PB est réalisée vis-à-vis de complexes plan carré d8 ML4. Deux modes de coordination sont mis en évidence présentant un acide de Lewis non impliqué dans la coordination P→M, puis en interaction avec un chlorure porté par le métal P→M-Cl→B.
Dans le quatrième chapitre, l'utilisation des composés diphosphine-borane PBP permet de mettre en évidence un troisième mode de coordination faisant apparaître une interaction M→B pour des complexes de rhodium, platine et palladium. L'analyse de cette interaction montre une forte dépendance vis-à-vis de la nature du métal.
Enfin, dans le cinquième chapitre la variation de la nature du précurseur métallique, ainsi que la modulation de l'acidité de Lewis du site accepteur conduisent à deux complexes d'or présentant une interaction originale Au-B par la coordination des composés mono-phosphine-borane PB.
L'ensemble de ce travail a été effectué en associant études expérimentales et études théoriques réalisées par Karinne Miqueu de l'Université de Pau et des Pays de l'Adour.
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Henderson, Steven G. D. "Spectroscopic studies of platinum halo-phosphine complexes." Thesis, University of Edinburgh, 1986. http://hdl.handle.net/1842/28226.
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Gammon, Jonathan J. "Chiral base-mediated desymmetrisation of phosphine sulfides." Thesis, University of York, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.516645.
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Douglas, Thomas Mark. "Chemistry of cationic rhodium alkyl phosphine complexes." Thesis, University of Oxford, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.504386.
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Nelson, Adam Stephen. "The asymmetric dihydroxylation of allylic phosphine oxides." Thesis, University of Cambridge, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.627579.
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Clayden, Jonathan Paul. "The asymmetric epoxidation of allylic phosphine oxides." Thesis, University of Cambridge, 1992. https://www.repository.cam.ac.uk/handle/1810/272241.
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O'Brien, Peter Andrew. "Enantio- and diastereoselective reactions with phosphine oxides." Thesis, University of Cambridge, 1995. https://www.repository.cam.ac.uk/handle/1810/271960.
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Lake, Andrew J. "Advances in polyaromatic and ferrocenyl phosphine chemistry." Thesis, Loughborough University, 2010. https://dspace.lboro.ac.uk/2134/6329.
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Condensation of Ph2PCH2OH with a range of polyaromatic substituted secondary amines afforded a new set of 'hybrid' phosphine ligands of the type {RCH2N(CH2PPh2)CH2}2 and RCH2N(CH2PPh2)CH2CH3 (R = various planar aromatic groups). The coordination chemistry of these new mono and bidentate ligands towards a range of transition metal centres including Mo(0), Au(I), Rh(I), Ni(II), Pd(II), Pt(II) and Ru(II) was investigated. Ditertiary phosphines of the form {RCH2N(CH2PPh2)CH2}2 were found to be capable of bridging two transition metal centres in addition to forming rare examples of nine-membered cis- and trans- chelate complexes. Single crystal X-ray analysis of these coordination compounds revealed several types of inter- and intramolecular packing interactions (including a C-H···Pt interaction and slipped intermolecular π····π stacking), and also confirmed the rare trans-diphosphine coordination mode. Fluorescent emission measurements have been undertaken on these new tertiary phosphines and their coordination compounds, and these luminescent properties are discussed. A preliminary investigation into the chemosensory behaviour of selected compounds has been undertaken. Using RPCH2OH (RP = Ph2P, Cy2P or AdP = 1,3,5,7,-tetramethyl-2,4,8-trioxa-6- phosphaadamantane) as a versatile precursor, a range of ferrocenyl (Fc) tertiary phosphines have been prepared from a selection of primary and secondary amines. The coordination chemistry of these new mono and bidentate ligands towards several transition metal centres including Cr(0), Mo(0), Au(I), Rh(I), Ru(II), Pd(II) and Pt(II) was investigated. In particular, the previous chemistry was expanded to prepare several new diferrocenyl phosphines of the form {FcCH2N(CH2PR)CH2}2. In a similar manner to their polyaromatic counterparts, these ditertiary phosphines were found to be capable of coordination through both bridging and cis- / trans-chelating modes. Notably, single crystal X-ray analysis was used to confirm the formation of an extremely rare example of a dimeric trans, trans-[Rh(CO)Cl{phosphine}2]2 complex; thought to be the first crystallographically characterised metallacycle containing an Rh2Fe4 arrangement of metal centres. In addition to this {FcCH2N(CH2PR)CH2}2 chemistry, a rare example of a triferrocenyl ditertiary ii phosphine, {FcCH2N(CH2PPh2)CH2}2Fc, was prepared, as well as a macrocyclic ditertiary ferrocenyl phosphine, C10H8Fe(CH2N(CH2PPh2)CH2)2CH2. The coordination chemistry of {FcCH2N(CH2PPh2)CH2}2Fc led to the formation of two unusual examples of pentametallic diphosphine coordination complexes with a Fe3Au2 and Fe3Ru2 arrangement of metal centres. The development of a new phosphinoamine, (Ph2P)2NCH2Fc, and a new ferrocenyl iminophosphine, Ph2PCH(Ph)CH2C(H)NCH2Fc, are also discussed, in addition to a brief investigation of their coordination chemistry. Electrochemical measurements have also been undertaken on these ferrocenyl ligands and their respective coordination compounds (when purity, yield and stability would allow), and their redox chemistry discussed. A series of novel phosphorus(III) containing ligands of the forms (R)N(CH2PPh2)2 and (R)NHCOCH2N(CH2PPh2)2 (R = functionalised planar aromatic or ferrocenyl group) have been prepared. The phosphines were found to readily coordinate several transition metals including Pt(II), Pd(II) and Ru(II) to form a series of new cis- chelate and bridged bimetallic complexes. Analysis by single crystal X-ray diffraction revealed several types of inter- and intramolecular hydrogen bonding within the molecular structures of the phosphines and their coordination compounds, including the formation of several intermolecular 1D chains and the presence of an intramolecular N-H···N bond, which forces a 'scorpion-like' conformation.
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Jatcko, Mark Edward. "Ionization-structure relationships in metal-phosphine interactions." Diss., The University of Arizona, 1989. http://hdl.handle.net/10150/184942.
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The techniques of valence photoelectron spectroscopy (PES), X-ray diffraction, molecular orbital calculations, and multi-nuclear NMR are combined in a comparison of metal-phosphine bonding in a series of phosphine substituted molybdenum and tungsten metal carbonyl complexes, M(CO)(6-n)(P)(n) [n = 1,2,3,4,6]. The phosphine, P, represents either the mono-dentate phosphine, PMe₃, or one phosphine unit in the diphosphines, Me₂P(CH₂)ₓPMe₂, [x = 1, bis(dimethylphosphino)methane (DMPM); x = 2, 1,2-bis(dimethylphosphino)ethane (DMPE)]. Comparison of PMe₃ and the diphosphines in mono-dentate coordination (i.e. η¹-Mo(CO)₅DMPE) indicates the σ-donor strength is essentially identical for the three phosphines studied. Comparison of PMe₃ and the diphosphines in cis-chelating geometries reveals essentially identical charge at the coordinated phosphorus atoms and nearly identical charge at the metal center for cis-M(CO)₄(PMe₃)₂ and cis-M(CO)₄DMPE despite different local P-M-P bond angles. The X-ray crystal structures reveal a "twist" of the phosphine ligand when in sterically strained coordination geometries. The phosphine twist results in a "bent" metal-phosphine bond and is evaluated based on both electronic and steric considerations. The phosphine twist principle is used in studies on the nature of phosphine ligand electronic effects in the M(CO)(6-n)(P)(n) series at high substitution numbers, n. The PES data of the DMPE complexes for n = 4, cis-Mo(CO)₂(DMPE)₂, and n = 6, Mo(DMPE)₃, show symmetric metal electronic structure, but also a deviation from the previously observed additive behavior of phosphine electronic effects. The PES data for cis-Mo(CO)₂(PMe₃)₄ reveal a symmetric metal electronic structure due to sterically induced ligand-ligand interactions in this metal carbonyl complex. Multi-nuclear NMR data (³¹P and ⁹⁵Mo) are presented and the results discussed in light of the important ligand-ligand interactions observed in the PES studies. In addition, comparison of the NMR results for the mono-dentate and chelating phosphine complexes and the PES metal electronic structures provides a possible contribution to the ring chelate effect that is observed in the ³¹P and ⁹⁵Mo chemical shifts. The ring chelate effect refers to the unexplained relative differences between the ³¹P and ⁹⁵Mo chemical shifts of the cis-(PR₃)₂ complexes and the chelating diphosphine analogues.
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Merle, Nicolas. "Transition metal complexes of chelating phosphine boranes." Thesis, University of Bath, 2006. https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.426296.
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