Rozprawy doktorskie na temat „Organometallic catalysts”
Kliknij ten link, aby zobaczyć inne rodzaje publikacji na ten temat: Organometallic catalysts.
Utwórz poprawne odniesienie w stylach APA, MLA, Chicago, Harvard i wielu innych
Sprawdź 50 najlepszych rozpraw doktorskich naukowych na temat „Organometallic catalysts”.
Przycisk „Dodaj do bibliografii” jest dostępny obok każdej pracy w bibliografii. Użyj go – a my automatycznie utworzymy odniesienie bibliograficzne do wybranej pracy w stylu cytowania, którego potrzebujesz: APA, MLA, Harvard, Chicago, Vancouver itp.
Możesz również pobrać pełny tekst publikacji naukowej w formacie „.pdf” i przeczytać adnotację do pracy online, jeśli odpowiednie parametry są dostępne w metadanych.
Przeglądaj rozprawy doktorskie z różnych dziedzin i twórz odpowiednie bibliografie.
1
Kerton, Francesca Maria. "Organometallic based transition metal catalysts". Thesis, University of Sussex, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.285060.
Pełny tekst źródła
2
Craig, Kim Meyer. "New concepts in catalyst design: homogeneous organometallic catalysts with tunable architectures". Thesis, University of Auckland, 2010. http://hdl.handle.net/2292/6114.
Pełny tekst źródłaStreszczenie:
This theses describes the development of homogeneous catalysts containing receptor elements which are capable of participating in reversible bonding interactions with groups bearing complementary functionality. This approach is amenable to combinatorial chemistry, and could facilitate catalyst development processes which are conventionally expensive and time-intensive. To date, the implication of reversible supra molecular interactions in anthropogenic organometallic catalysis are not widely understood.
3
Lev, Daniel Abraham. "Group 8 and 9 half sandwich complexes of N-heterocyclic phosphines : synthesis, reactivity, and catalysis /". Diss., Connect to a 24 p. preview or request complete full text in PDF format. Access restricted to UC campuses, 2004. http://wwwlib.umi.com/cr/ucsd/fullcit?p3158465.
Pełny tekst źródła
4
Pearson, Mark. "Organometallic reagents for catalytic cross-coupling". Thesis, University of Oxford, 1992. http://ora.ox.ac.uk/objects/uuid:c5eea9a0-8f0c-46bf-a1ea-28a40b79546d.
Pełny tekst źródłaStreszczenie:
Phosphine complexes of nickel and palladium provide the best catalysts for the homogeneous catalysed carbon-carbon bond forming reaction between an organometallic nucleophile and an organic electrophile. Use of a homochiral ligand on the catalyst can lead to stereoselectivity in the cross-coupling reaction, with high ee's of coupled product being obtained. The processes of selectivity in the transmetalation step of the catalytic cycle have not been elucidated and the initial aim of the project was to study these processes. Initial experiments using organotin derivatives as the organometallic nucleophile highlighted the problems of selectivity and the forcing conditions needed in the attempted transfer of a benzyl group from the tin to the palladium catalyst. The compounds [8- (dimethylamino)-1-naphthyl]methyldiphenyltin (60) and [2-((dimethylamino)methyl) phenyl]methyldiphenyltin (70) were prepared and their reactivity in the palladium catalysed cross-coupling with 2-furoyl chloride, to give 2-benzoylfuran, was investigated. These molecules were found to undergo facilitated transfer of a phenyl group compared to transfer from control molecules. The effect was tested and attributed to the internal nucleophilic attack at the tin atom by the lone pair on the nitrogen atom. The compound [2- ((dimethylamino)methyl)-3-trimethylsilylphenyl]methyldiphenyltin (79) was prepared to test the effects of steric buttressing within the molecule, but was found to be of the same order of magnitude of reactivity as (60) and (70). All three molecules showed a reactivity of at least an order of magnitude greater than control compounds. The effect did not prove applicable to the transfer of a benzyl group or in other coupling reactions. The effect of palladium ligation was tested and the ligand triphenyl arsine found to increase the rate of the coupling reaction. The two facilitating processes were found to work in a co-operative fashion, giving a rate enhancement of ca. one hundredfold over control reactions. The nickel catalysed cross-coupling of α-substituted sp3 hybridised Grignard reagents with allylic esters was attempted, but proved unsuccessful. Stoichiometric reactions with nickel complexes were also found to be unsatisfactory in yielding coupled products. The synthesis of α-substituted diorganozinc reagents was attempted, but furnished only homocoupled products. The reaction of dibenzylzinc with aldehydes was found to proceed in the absence of catalyst, highlighting the reactivity of a benzylzinc moiety.
5
Rumble, Sarah Louise Chemistry Faculty of Science UNSW. "The synthesis of amines and imines organometallic catalysts". Awarded by:University of New South Wales. School of Chemistry, 2005. http://handle.unsw.edu.au/1959.4/23422.
Pełny tekst źródłaStreszczenie:
This thesis describes investigations into the catalysed syntheses of amines and imines using organoiridium and organorhodium complexes with N-donor ligands as the catalysts. These catalysed syntheses were achieved via hydroamination, hydrosilylation, and hydrogenation reactions, as well as tandem hydroamination/imine reduction reactions. An in situ catalysis study found that the most active catalysts for the hydroamination of 4-pentyn-1-amine (1) to give 2-methyl-1-pyrroline (4) were formed from a combination of catalyst components that resulted in an electron deficient metal centre, indicating that an alkyne binding mechanism was most likely. The kinetics of the hydroamination of 4-pentyn-1-amine (1), catalysed by the complexes [Rh(bim)(CO)2][BPh4] (7), [Ir(bim)(CO)2][BPh4] (8), [Rh(bpm)(CO)2][BPh4] (9),and [Ir(bpm)(CO)2][BPh4] (10) (bpm = bis(1-pyrazolyl)methane and bim = bis(Nmethylimidazol- 2-yl)methane) were modelled and compared. The nature of the metal centre was found to have the most influence on the rate of the product release step, while the nature of the N-donor ligand was found to have the most influence on the rate of the substrate binding step. The investigation of the catalysed hydroamination of the phenyl substituted alkynylamines 5-phenyl-4-pentyn-1-amine (2), 4-phenyl-3-butyn-1-amine (13) and 2- phenyl-4-pentyn-1-amine (34) revealed a difference in catalytic activity between the rhodium and iridium complexes depending on the alkyne substituent. A series of novel rhodium(I) complexes were synthesised: [RhClCO(Mes-DAD(Me))] (38), [RhClCO(Mes-BIAN)] (22), [Rh(COD)(Mes-BIAN)][BF4] (39), [Rh2(COD)2(bmimen)](BPh4)2 (40) and [Rh2(CO)4(bmimen)](BPh4)2 (41), where Mes- DAD(Me) = biacetylbis(2,4,6-trimethylphenylimine), Mes-BIAN = bis(2,4,6- trimethylphenylimino)acenapthene and bmimen = 1,2-bis[(1-methyl-2- imidazolyl)methylene-amino]ethane. The cationic complex 40 was found to be an active hydroamination catalyst, while the neutral complexes 38 and 22 were only active in the presence of the tetraphenylborate counterion. A range of imines was found to be efficiently reduced to their respective amines via hydrosilylation or hydrogenation using the iridium(I) complex [Ir(bpm)(CO)2][BPh4] (10) as catalyst. The hydrosilylation reaction was found to be significantly faster in a protic solvent (methanol), giving the desilylated amines without the need for a desilylation step. The mechanism of this reaction was proposed to involve a monohydride iridium(I) complex as a key intermediate. The tandem hydroamination/hydrosilylation of a series of alkynylamine substrates was achieved using the iridium complexes 8 and 10, in which the iridium complex catalyses the two mechanistically distinct reactions in the one-pot. Catalysed tandem hydroamination/hydrogenation reactions were also achieved, but were less facile.
6
Gregson, Charlotte Katherine Anne. "Towards redox control of organometallic molecular polymerisation catalysts". Thesis, Imperial College London, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.428536.
Pełny tekst źródła
7
Manville, Charles. "New organic and organometallic catalysts for asymmetric synthesis". Thesis, University of Warwick, 2010. http://wrap.warwick.ac.uk/35525/.
Pełny tekst źródłaStreszczenie:
Monodentate phosphorus ligands based on BINOL have been synthesised and applied to metal catalysed pressure hydrogenation and conjugate addition. Novel phosphorus containing enantioselective organocatalysts have been synthesised from DPEN and proline, and studied in the Michael addition of acetone to trans-β- nitrostyrenes, with up to 96 % e.e. The optimum reaction conditions for reaction rate and enantioselectivity have been investigated. Related proline-DPEN coupled organocatalysts have been synthesised and applied to the coupling reaction between DEAD and aldehydes. The proline-DPEN coupled compounds have been investigated for uses as ligands in the ruthenium catalysed asymmetric transfer hydrogenation of ketones in an aqueous medium. The hydrogenation reactions can be performed with good conversions and up to 98% e.e.
8
Marshall, Robert. "Preparation of bimetallic catalysts by surface organometallic chemistry". Thesis, Open University, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.265345.
Pełny tekst źródła
9
Liang, Jack S. (Jack Shih-Chieh) 1972. "Development and applications of enantioselective organometallic catalysts : I. Organotin catalysts; and, II. Planar-chiral nitrogen heterocyclic catalysts". Thesis, Massachusetts Institute of Technology, 1999. http://hdl.handle.net/1721.1/85292.
Pełny tekst źródła
10
Haslam, Claire Elizabeth. "Organometallic mechanisms and reactivity : towards new catalysts for polyketones". Thesis, University of Sheffield, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.310787.
Pełny tekst źródła
11
Perriam, Joseph John. "Hybrid inorganic-organometallic catalysts derived from #alpha#-zirconium phosphate". Thesis, University of Exeter, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.264608.
Pełny tekst źródła
12
Scott, Richard T. W. "Group 4 amidinate complexes as olefin polymerisation catalysts". Thesis, University of Oxford, 2012. http://ora.ox.ac.uk/objects/uuid:69980bfb-d3bf-4232-9580-c661bf92c1ec.
Pełny tekst źródła
13
Wright, Christopher. "Supported tungsten imido and iridium pincer catalysts towards tandem hydrocarbon upgrading". Thesis, University of Oxford, 2017. https://ora.ox.ac.uk/objects/uuid:9ab35e6d-903d-4eeb-9d33-3c8e637aba97.
Pełny tekst źródłaStreszczenie:
The principle aims of this thesis have been to develop well-defined heterogeneous catalysts for potential applications in tandem hydrocarbon upgrading. Catalysts for olefin oligomerisation and metathesis of &alpsha;-olefins and transfer hydrogenation of alkanes based on tungsten mono-imido and PCP pincer iridium complexes have been synthesised and immobilised on solid supports. The reactivity of the immobilised catalysts has been tested and compared with the precursor complexes. Co-immobilisation of the two complexes on the same support has been undertaken. Chapter One provides a background to the olefin metathesis reaction and the development of highly active tungsten mono-imido and ruthenium alkylidene complexes. A summary of the implementation of the olefin oligomerisation reaction by industry and the development of highly active systems based on group 6 metals is discussed, along with a mechanistic discussion. The SOMC grafting procedure is considered and the immobilisation of catalysts for alkane and olefin metathesis and oligomerisation discussed; with focus on support materials: silica, sMAO and AMO-LDHs. Finally, tandem catalysis and its use in hydrocarbon upgrading and copolymerisation are presented. Chapter Two details the synthesis of W(NR)Cl4(THF) complexes and their conversion to W(NR)Me3Cl complexes employing TMA. The products are characterised by single crystal X-ray diffraction, NMR and FTIR spectroscopy. W(NR)Me3Cl complexes are shown to be active for the selective dimerisation of ethylene to 1-butene. Attempted formation of possible intermediates in the reaction is presented, and efforts to form mimics for silica supported species are also discussed. Chapter Three describes the preparation of AMO-LDHs for use as catalyst supports. The effect on the surface hydroxyl content and structural properties of these materials by thermally treating them under vacuum is analysed. Their capability to act as supports for ethylene polymerisation after impregnation with MAO and (nBuCp)2ZrCl2 is described. Chapter Four investigates the immobilisation and characterisation of synthesised tungsten mono-imido complexes on sMAO, AMO-LDHs and silica, utilising SSNMR, FTIR and X-ray absorption spectroscopy. The reactivity of the grafted complexes towards ethylene oligomerisation is discussed. For the immobilised species effects of varying the imido ligand, temperature and solvent medium are reported. Attempts to immobilise ruthenium carbene complexes on AMO-LDHs and sMAO is detailed. Chapter Five gives an account of the immobilisation of Ir(tBuPCP)HCl on sMAO which is characterised by SSNMR and FTIR spectroscopy. Molecular analogues of the supported species are synthesised and reactivity for the hydrogenation of ethylene compared. Transfer hydrogenation reaction with sMAO-Ir(tBuPCP)HCl and COA or ethane with TBE as a sacrificial H2 acceptor are discussed. Finally, co-immobilisation of W{N(2,6-F-C6H3)}Cl4(THF) and Ir(tBuPCP)HCl on sMAO was carried out and the solid characterised by SSNMR spectroscopy. Chapter Six provides experimental details and characterising data for the preceding chapters. An Appendices with crystallographic data, and characterising spectra for each chapter is provided, while the Electronic Appendix contains a combined CIF and checkcif for all the molecular structures presented.
14
Cairns, Graham R. "Hydrogenation catalysts from supported palladium complexes". Thesis, University of Glasgow, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.360177.
Pełny tekst źródła
15
Du, Shuoren. "Towards redox control of organometallic catalysts bearing ferrocene-based ligands". Thesis, Imperial College London, 2013. http://hdl.handle.net/10044/1/23902.
Pełny tekst źródłaStreszczenie:
This project focuses on the design and synthesis of redox active palladium and rhodium complexes containing ferrocene moieties, and the influence of switching the oxidation state of the ligand on the catalytic behaviour of the metal centre. The redox effect on the catalyst is investigated via carbonylation, hydrogenation and Suzuki cross-coupling reactions. Chapter 1. Introduction to redox-controlled catalysis and palladium-catalyzed carbonylation reactions. The categorization of redox active ligands, and the use of electrochemistry as a tool for choosing the right chemical redox agent are discussed. The aims of the project are outlined. Chapter 2. Chemical oxidation of a series of palladium complexes containing bidentate ferrocen-1,1'-diphosphines, and their catalytic behaviour towards the carbonylation reactions of aryl halides compared with the non-oxidized complexes are reported. A hypothesis is proposed to explain the difference in the catalytic reactivities of the same complex with a different state of charge of the ligand. Chapter 3. The synthesis of a series of new bidentate ligands from ferrocenylamine and their palladium complexes is reported. The electrochemical properties of these palladium N-P complexes are described, as well as their performance as catalysts for carbonylation reactions. Chapter 4. An improved method for the purification of halogenated feorrcenes is included in this chapter. The synthesis of other groups of ferrocene-based ligands and their complexation towards new palladium N-N complexes is reported. Chapter 5. Attempts to realize redox control on other catalytic processes, such as palladium-catalyzed Suzuki cross-coupling reactions and rhodium-catalyzed hydrogenation, is discussed. Chapter 6. Conclusions and future work of this project. Chapter 7. Experimental details. References are included in each of these chapters.
16
Figg, Travis M. "Modeling Transition Metal Catalysts for Small Molecule Activation and Functionalization". Thesis, University of North Texas, 2013. https://digital.library.unt.edu/ark:/67531/metadc271814/.
Pełny tekst źródłaStreszczenie:
There is a high demand for the development of processes for the conversion of ubiquitous molecules into industrially useful commodities. Transition metal catalysts are often utilized for the activation and functionalization of small organic molecules due to their diverse nature and proven utility with a myriad of chemical transformations. The functionalization of methane (CH4) and dinitrogen (N2) to methanol (CH3OH) and ammonia (NH3) respectively is of particular interest; however, both methane and dinitrogen are essentially inert due to the inherit strength of their bonds. In this dissertation a series of computational studies is performed to better understand the fundamental chemistry behind the functionalization of methane and the activation of dinitrogen in a homogeneous environment. A catalytic cycle is proposed for the oxy-functionalization of methane to methanol. The cycle consists of two key steps: (1) C-H activation across a metal-alkoxide bond (M-OR), and (2) regeneration of the M-OR species through an oxy-insertion step utilizing external oxidants. The C-H activation step has been extensively studied; however, the latter step is not as well understood with limited examples. For this work, we focus on the oxy-insertion step starting with a class of compounds known to do C-H activation (i.e., Pt(II) systems). Computational studies have been carried out in an attempt to guide experimental collaborators to promising new systems. Thus, the majority of this dissertation is an attempt to extend transition metal mediated C-O bond forming reactions to complexes known to perform C-H activation chemistry. The last chapter involves a computational study of the homogeneous cleavage of N2 utilizing iron-?-diketiminate fragments. This reaction has been studied experimentally, however, the reactive intermediates were not isolated and the mechanism of this reaction was unknown. Density functional theory (DFT) calculations are carried out to elucidate the mechanism of the reductive cleavage of N2 via the sequential addition of iron- ?-diketiminate fragments to N2 to form a bis-nitride (N3-) intermediate. The role of potassium promoters on the dinitrogen and bis-nitride species is also investigated.
17
PANG, LOUIS SING KIM. "THE ELECTRONIC STRUCTURES OF ORGANOMETALLIC ALKYNE AND VINYLIDENE COMPLEXES AS DETERMINED BY X-RAY AND ULTRAVIOLET PHOTOELECTRON SPECTROSCOPY (CYCLOPENTADIENYL, VALENCE, MANGANESE, CORE, VANADIUM)". Diss., The University of Arizona, 1985. http://hdl.handle.net/10150/188072.
Pełny tekst źródłaStreszczenie:
The chemistry and bonding of alkynes and vinylidenes in organometallic complexes have been investigated. A variety of these complexes have been synthesized and characterized by X-ray crystallography, temperature-dependent NMR, molecular orbital calculations, and most importantly, HeI, HeII and MgKα photoelectron spectroscopy (PES). The core and valence ionizations are found to be very informative with regard to the relative bond strengths and stabilities of these complexes. The first step involved preparation of the series of complexes R-CpM(CO)₂(alkyne) (R-Cp = Cp, MeCp and Me₅Cp). When M = Mn, Re (alkyne = 3-hexyne, 2-butyne and hexafluoro-2-butyne), the molecular mirror plane bisects the alkyne (horizontal conformation). PES shows the alkyne (π(⊥)) orbital forms a filled-filled interaction with the frontier metal orbital which is significantly destabilized. The ionizations derived from the two alkyne π orbitals are not split. When M = V, the alkyne (C₂H₂, 3-hexyne, etc.) coincides with the molecular mirror plane (vertical conformation). PES shows the alkyne π(⊥) orbital donates electrons to the electron deficient vanadium and the metal backbonds strongly to the alkyne. Electronic factors controlling the conformations in the d⁶ manganese case has been much discussed in the literature. Another factor not previously identified is necessary for understanding the conformation in the d⁴ vanadium case. The energy of the LUMO reveals that this factor is donation of cyclopentadienyl electrons into an empty d orbital of the electron deficient vanadium. Rearrangement of alkyne complexes to terminal vinylidene and bridging vinylidene complexes, similar to reactions of organic molecules on metal surfaces, were also investigated. The series of [R-CpMn(CO)₂]₂(μC=CHR') (R' = H, Me) (Chapter 6) and CpMn(CO)₂(C=CHBuᵗ) (Chapter 7) complexes were prepared. PES showed that the terminal vinylidene ligand has less filled-filled interaction with the metal and stabilizes the metal more than the alkyne does. The bridging vinylidene accepts more electron density from the metals and stabilizes the metals more than the terminal vinylidene. The removal of antibonding electrons from the HOMO of the metal fragment by the bridging vinylidene leaves net metal-metal bonding interaction and forms a stable dimetallocyclopropane structure.
18
Escárcega, Bobadilla Martha Verónica. "Organometallic compounds and metal nanoparticles as catalysts in low environmental impact solvents". Doctoral thesis, Universitat Rovira i Virgili, 2011. http://hdl.handle.net/10803/9114.
Pełny tekst źródłaStreszczenie:
Durant les darreres dècades, el disseny de processos en el marc de la química sostenible ha anat creixent de forma exponencial. La recerca constant de processos mes benignes amb el medi ambient ha implicat un gran esforç per obtenir millors rendiments mitjançant l'activació de llocs específics, i possant especial èmfasi amb el control de la quimio-, la regio- i la enantioselectivitat, punts crucials per a l'economia atómica. En aquest sentit, els dissolvents juguen un paper crític, i com podrà veure's al llarg d'aquesta memòria..Aquesta Tesi s'enfoca en l'ús de mitjans de reacció alternatius i sostenibles, com són els líquids iònics (ILs), el diòxid de carboni supercrític (scCO2) i la barreja de ambdós dissolvents, amb l'objectiu de disminuir l'ús de dissolvents orgànics convencionals i la seva aplicació en els següents processos catalítics: hidrogenació asimètrica, reacció de Suzuki d'acoblament creuat C-C, reacció d'alquilació al·lílica asimètrica i la hidrogenació de arens.
In the last decades, the design of processes in the framework of the sustainable chemistry has been exponentially growing. The constant searching of cleaner processes has led to a lot of effort to obtain higher yields by activation of specific sites, and improving chemo-, regio- and enantio-selectivities, which are crucial from a point of view of an atom economy strategy. In this sense, solvents play a critical role.
This PhD thesis focuses on the use of alternative sustainable reaction media such as ionic liquids (ILs), supercritical carbon dioxide (scCO2) and mixtures of both solvents in different catalytic processes, with the aim of decreasing the use of conventional organic solvents applied in the following catalytic reactions: homogeneous and supported rhodium catalysed asymmetric hydrogenation, biphasic palladium catalysed Suzuki C-C cross-coupling, homogeneous palladium catalysed asymmetric allylic alkylation, and ruthenium and rhodium nanoparticles catalysed arene hydrogenation were tested.
19
Bennett, Malcolm William. "Design of new asymmetric copper(I)-catalysts for conjugate addition chemistry". Thesis, University of Hull, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.310254.
Pełny tekst źródła
20
Diebolt, Olivier. "N-heterocyclic carbene ligands in palladium and iridium organometallic chemistry". Thesis, University of St Andrews, 2010. http://hdl.handle.net/10023/2126.
Pełny tekst źródłaStreszczenie:
The use of ligand in transition-metal catalysed reactions has had a considerable impact. The present manuscript aims at showing the influence of ligands in the palladium catalysed Suzuki-Miyaura cross-coupling reaction. In chapter one, the mechanism of this reaction will be described based on the numerous contribution published in the literature. It will be shown that the electronic and steric properties of the ligands have a huge repercussion on the catalytic activity of the metal. In the second chapter, the electronic and steric properties of the widely used Buchwald-phosphine ligand will be investigated. For this purpose, bis-carbonyl iridium(I) complexes were synthesized and their characterization allowed determining their TEP (Tolman electronic parameter) and their buried volume %V[subscript(bur)]. Then three next chapters of this thesis will focus on the syntheses and characterizations of new palladium complexes bearing N-heterocyclic carbenes (NHC). Their design was made in a view to obtain high activity in cross coupling reaction, particularly in the Suzuki-Miyaura cross coupling. Their activation under the catalytic conditions leads to the formation of palladium(0) species that can be mono- or bis-ligated. The influence of the ligand on the catalyst activity will be discussed. A palladium(II) precatalyst leading to mono-ligated active species will be described. Its activity in cross-coupling is very good, since activated and non-activated aryl chlorides could be coupled with aryl boronic acids at room temperature using low catalyst loadings. Unfortunately, the catalyst activity decreased with temperature. This result showed the fragility of the mono-ligated active species. In a view to obtain more robust catalysts that can perform high turnover numbers, new palladium(II) precatalysts bearing two ancillary ligands were developed. Mixed systems NHC- phosphites and NHC-phosphines are described. NHC-phosphites precatalysts displayed very good activity, but the phosphites are unfortunately sensitive to reaction conditions, limiting their role of active species shield. NHC-phosphine bearing complexes were highly active and could perform up to 10,000 turnovers with unactivated aryl chlorides. Very interestingly, these catalysts were also able to couple benzylchlorides and allyl chlorides with a wide range of boronic acids at very low catalyst loadings. These reactions had also the great advantage to proceed in aqueous solvents at very high substrate concentration. The activation mechanism of these complexes was investigated. Dichloropalladium(II) complexes were reduced under the catalytic conditions to lead palladium(0) species. Therein, it is shown that this reduction step was rate-determining in catalysis. Some palladium(0) intermediates xxiv were synthesized and showed good to excellent activities at low temperature under the exact same conditions. They displayed high reactivity towards oxygen and moisture and have to be handled under inert atmosphere. A particular complex had the ability to react with molecular dioxygen to form a stable peroxo-complex. Interestingly, this complex displayed excellent activity in water under aerobic conditions. This system was of great advantage since the reaction could be set up under air using cheap and user-friendly reagents displaying low toxicity. Moreover, the readily available distilled water used as solvent did not require prior degassing. Symmetrical and unsymmetrical bis-NHC palladium(0) complexes were successfully synthesized. They display excellent activity in the Suzuki-Miyaura cross coupling and turnover frequencies as high as 300 could be obtained at room temperature with unactivated arylchlorides and arylboronic acids. These complexes were also found excellent catalysts for the coupling of benzylchlorides with arylboronic acids. Mechanistic studies showed that no ligand dissociation occurred during the coupling suggesting as bis-ligated active species.
21
Morley-Smith, Neil A. "Early transition metal chemistry incorporating the disubstituted dianionic rings cyclooctatetraenyl and pentalenyl". Thesis, University of Sussex, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.364544.
Pełny tekst źródła
22
Reid, Amanda Julietta. "X-ray crystallographic studies of organometallic complexes and the determination of the structure of nickel (II) insulin". Thesis, Liverpool John Moores University, 1993. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.262263.
Pełny tekst źródła
23
Scharbert, Maren Theresa. "The synthesis and study of titanium amidinate complexes as olefin polymerisation catalysts". Thesis, University of Oxford, 2018. http://ora.ox.ac.uk/objects/uuid:85319c3f-8b2e-4e28-a90b-27444ce9f266.
Pełny tekst źródłaStreszczenie:
This Thesis is concerned with the synthesis of post-metallocene group 4 amidinate complexes as pre-catalysts for the polymerisation and oligomerisation of α-olefins. Activation of half-sandwich group 4 amidinate complexes with 1,3-conjugated dienes is also investigated and their underlying chemistry is explored. Chapter 1 introduces homogeneous Ziegler-Natta catalysis, with a specific focus on group 4 compounds. A review of metallocene and post-metallocene complexes of group 4 will also be presented and their behaviour in olefin polymerisation will be discussed. Chapter 2 describes the synthesis and characterisation of K1-amidinate supported titanium complexes. Base-free activation of the titanium cyclopentadienyl-amidinate dialkyl complexes will be investigated and the resulting cationic species will be further explored with commonly applied trapping agents. The synthesis and characterisation of new titanium cyclopentadienyl-amidinate diene complexes and their corresponding tri(pentafluorophenyl)borane-activated zwitterionic compounds will also be described and their performance in the co-polymerisation of ethylene and propylene will be discussed. Chapter 3 explores the addition of 1,3-conjugated diene reagents to titanium cyclopentadienyl-amidinate and guanidinate alkyl cations. Mechanistic and computational studies of allyl and diene formation will also be described. The polymerisation capabilities of the newly formed complex will be discussed and compared to previously reported dialkyl complexes. Chapter 4 describes the synthesis and characterisation of aminopyridinato titanium complexes and K1-K2-bis(amidinate) titanium complexes. The activation chemistry of the newly formed dialkyl complexes will be investigated. Furthermore, the synthesis of a new bis(aminopyridinato) titanium complex will also be discussed alongside their activity in EPM and EPDM polymerisation. Chapter 5 describes the performance of the aminopyridinato titanium complexes (synthesised in Chapter 4) in EPDM polymerisation. The sensitivity of the aforementioned complexes towards hindered phenols will also be discussed and their behaviour in ethylene oligomerisation will be explored. Chapter 6 presents full experimental procedures and characterising data for the new complexes reported in this Thesis.
24
Capapé, Miralles Alejandro. "Rhenium, molybdenum and tungsten organometallic homogeneous catalysts : synthesis, characterisation and application in olefin epoxidation". München Verl. Dr. Hut, 2009. http://mediatum2.ub.tum.de/node?id=806954.
Pełny tekst źródła
25
Naidoo, Qiling Ying. "Multicomponent catalysts for methanol electro-oxidation processes synthesized using organometallic chemical vapourde position technique". Thesis, University of the Western Cape, 2011. http://etd.uwc.ac.za/index.php?module=etd&action=viewtitle&id=gen8Srv25Nme4_7491_1320654024.
Pełny tekst źródłaStreszczenie:
In this study, the OMCVD method is demonstrated as a powerful, fast, economic and environmental friendly method to produce a set of PGMelectrocatalysts with different supports, metal content and metal alloys in one step and without the multiple processing stages of impregnation, washing, drying, calcinationsand activation.
26
Lai, Felix ShangChung. "Metal oxide-supported cluster catalysts derived from organometallic precursors : spectroscopic characterization in reactive environments /". For electronic version search Digital dissertations database. Restricted to UC campuses. Access is free to UC campus dissertations, 2003. http://uclibs.org/PID/11984.
Pełny tekst źródła
27
Shaffer, Andrew Ronald. "Synthesis, reactivity, and catalysis of 3-iminophosphine palladium complexes /". Connect to full text in OhioLINK ETD Center, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=toledo1248288981.
Pełny tekst źródłaStreszczenie:
Thesis (Ph. D.)--University of Toledo, 2009.Typescript. "Submitted as partial fulfillment of the requirements for the Doctor of Philosophy in Chemistry." Includes bibliographical references (leaves 183-217).
28
Dyer, Philip William. "Studies on molecular Oxo and Imido complexes of the group 6 metals and supported chromium oxide polymerisation catalysts". Thesis, Durham University, 1993. http://etheses.dur.ac.uk/5778/.
Pełny tekst źródłaStreszczenie:
This thesis describes studies directed towards the preparation of bis (imido) complexes of the Group 6 metals containing olefin, phosphine, acetylene, and alkyl ligands with particular emphasis on their relationship with Group 4 bent metallocenes. The polymerisation mechanism of the Phillips catalyst (CrO(_3)/SiO(_2)) is examined using XPS (X-Ray Photoelectron Spectroscopy) and in situ mass spectroscopy. Chapter 1 highlights properties of some of the important ligand classes that are used throughout the remainder of this thesis. Chapter 2 describes a high yield one-pot synthesis of molybdenum bis (imido) complexes of the type Mo(NR')(NR")Cl(_2).DME. In addition a number of attempts to extend this strategy to other metals are described, including a novel synthesis of the chromium complex [Cr(_2)Cl(_9)] [NHEt(_3)](_3). Chapter 3 describes the synthesis, characterisation, and reactivity of the bis (imido) bis (phosphine) complexes Mo(NAr)(_2)(PMe(_3))(_2) and [Mo(N(^t)Bu)(µ-N(^t)Bu)(PMe(_3))](_2). Further studies on bis (imido) olefin complexes of the type Mo(NAr)(_2)(PMe(_3))2(η(^2)-C(_2)H (_2)) and Mo(N(^t)Bu)(_2)(PMe(_3))(η(^2)-C(_2)H(_4)) was undertaken and concentrated on their structural relationship to Group 4 metallocene species. Chapter 4 describes the preparation, structure, and reactivity of some bis (imido) acetylene complexes Mo(NR)(_2)(PMe(_3)) (PhC=CR’) (R= Ar, (^t)Bu; R'= Ph, H). Preparation of bis (imido) alkyls was undertaken in attempts to generate benzyne and alkylidene derivatives. Chapter 5 studies the Phillips polymerisation catalyst using XPS and mass spectroscopy. Model systems were used to probe reactive surface species their use reveals a number of features that are difficult to observe with the actual catalyst. Aspects of molecular chemistry have been examined which are believed to relate directly to the heterogeneous system allowing a possible polymerisation mechanism to be postulated. Chapter 6 gives experimental details for Chapters 2-5. Philip William Dyer (November 1993)
29
Lesieur, Mathieu. "Cu and Pd complexes of N-heterocyclic carbenes : catalytic applications as single and dual systems". Thesis, University of St Andrews, 2015. http://hdl.handle.net/10023/7999.
Pełny tekst źródłaStreszczenie:
Nowadays, the requirement to design highly valuable compounds is undoubtedly one of the major challenges in the field of organic and organometallic chemistry. The use of the versatile and efficient N-heterocyclic carbenes (NHCs) combined with transition metals represents a key feature in modern organometallic chemistry and homogeneous catalysis. In the course of this thesis, the straightforward design and synthesis of a library of Pd(0) bearing NHC ligands was achieved. Their catalytic performances (Chapter 1) and their phosphorescence properties in solution (Chapter 2) were disclosed. Currently, cross-couplings are some of the most important types of reaction in palladium catalysis. The formation of highly hindered biaryls substrates is one of the main requirements in cross-coupling chemistry. The design and synthesis of a palladium dimer bearing a bulky NHC ligand can fulfil this proposal (Chapter 4). The development of new classes of ligands is a topic of interest. For this reason, normal, abnormal, remote and mesoionic N-heterocyclic carbenes copper complexes were investigated and their reactivity compared in the [3+2] cycloaddition of azides and alkynes (Chapter 7). Air and moisture stable Cu(I)-NHC species have also been compared to their silver analogues for the alkynylation of ketones (Chapter 9). The different reactivity of the two latter organometallic species (Cu and Ag) with ethyldiazoacetate reagent via the formation of carbenes or C-H activated product is presented in Chapter 8. Recently, the development of a bimetallic catalytic system is strongly considered and has high impact. For this reason, two dual catalytic transformations (Pd-NHC and Cu-NHC) were studied for the C-H arylation (Chapter 5) and the synthesis of substituted alkenes products via a relay or cooperative mechanisms (Chapter 6). The isolation of intermediates and mechanistic studies were examined in each of these studies.
30
Kjellgren, Johan. "Employment of Palladium Pincer Complex Catalysts and Lewis Acids for Synthesis and Transformation of Organometallic Compounds". Doctoral thesis, Stockholm : Dept. of Organic chemistry, Arrhenius Laboratory, Univ, 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-416.
Pełny tekst źródła
31
Bolton, Sarah L. "Manipulation of the ligand sphere of ruthenium metathesis catalysts for the synthesis of organometallic molecular wires". Related electronic resource: Current Research at SU : database of SU dissertations, recent titles available full text, 2008. http://wwwlib.umi.com/cr/syr/main.
Pełny tekst źródła
32
Chakraborty, Arundhoti. "Development of Copper Catalysts for the Reduction of Polar Bonds". University of Cincinnati / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1479814963555246.
Pełny tekst źródła
33
Veenboer, Richard M. P. "Synthesis, study and application of NHC-gold(I) complexes". Thesis, University of St Andrews, 2017. http://hdl.handle.net/10023/12169.
Pełny tekst źródłaStreszczenie:
The development of procedures for the synthesis of valuable organic molecules constitutes an important part of chemistry. The goal of improving the efficiency of existing methodologies can be fulfilled by use of metal catalysts. Recent developments in the field of homogeneous gold catalysis have contributed to these efforts and continued investigations assure future innovations. Chapter 1 summarises the properties of gold and ligand-supported gold(I) complexes and demonstrates how a detailed understanding of its reactivity and possible bonding interactions with various substrates facilitates the development of well-defined catalytic systems. Particular attention is given to N-heterocyclic carbenes, highly tunable ligands that stabilise a wide range of different transition metal complexes. Three chapters describe syntheses and studies of known and new complexes. Chapter 2 discusses expedient syntheses of key NHC-gold(I) complexes and catalysts. Chapter 3 constitutes studies to the behaviour of the commonly used tetrafluoroborate counterion in a particular IPrCl -gold(I) complex. Chapter 4 de- scribes the synthesis of a range of IPr-gold(I) carbanion complexes from the widely studied IPr-gold(I) hydroxide synthon, the study of their properties and exploration of their reactivity. Catalytic applications in transformations of alkynes and alcohols are described in the last three chapters. Chapter 5 details the development of efficient NHC-gold(I)-catalysed procedures for the synthesis of vinyl ethers through addition reactions of aliphatic and benzylic alcohols to alkynes. Benzylic alcohols were found to undergo gold-catalysed dehydration under specific conditions and Chapter 6 discloses the NHC-gold(I)-catalysed dehydrative formation of ethers from phenols and benzylic alcohols. Appendix A describes preliminary explorations to the complimentary use of Brønsted acidic compounds as catalysts for the formation of products with new C – C bonds from benzylic alcohols and phenols.
34
Zanardi, Alessandro. "N-heterocyclic-carbene-based Ditopic and Hemicleaveable ligands for the design of improved catalysts". Doctoral thesis, Universitat Jaume I, 2010. http://hdl.handle.net/10803/669141.
Pełny tekst źródłaStreszczenie:
La presente memoria ha profundizado en el diseño de nuevos catalizadores al utilizar dos nuevos tipos de ligandos diferenciados: triazolil-di-ilideno y bis-alquenil-NHCs.
El uso del ligando trimetiltriazolil-di-ilideno, ha permitido obtener series de compuestos de tipo homo- y hetero-bimetálicos, estableciéndose criterios claros de coordinación que garantizan que el mismo ligando se puede utilizar de manera amplia en su coordinación a prácticamente cualquier par de fragmentos metálicos. La preparación y la caracterización de los compuestos heterobimetálicos establece un gran avance en el diseño de catalizadores tándem que permitan catalizar secuencias catalíticas formadas por reacciones muy diferentes.
La utilización de los ligandos de tipo bis-alquenil-NHC, ha permitido diseñar de forma sistemática compuestos en los que el ligando actúa como mono-, bi- y tri-dentado. Los compuestos derivados de la coordinación de los ligandos bis-alquenil-NHC han sido probados como catalizadores en reacciones de hidrosililación de alquinos, observándose que la actividad catalítica depende del grado de coordinación del ligando NHC. De este modo, los complejos monocoordinados y bisquelatos han mostrado las mejores actividades, junto a una elevada selectividad hacia los isomeros Z.
35
Cheng, Xu. "The Use of Functionalized Zirconocenes as Precursors to Silica-Supported Zirconocene Olefin Polymerization Catalysts". Diss., Virginia Tech, 2001. http://hdl.handle.net/10919/30027.
Pełny tekst źródłaStreszczenie:
Deck and coworkers previously showed that Me3Si substituents adjacent to group 4 metallocene dichlorides (M = Ti, Zr, Hf) are converted to corresponding BrMe2Si groups using BBr3, and that these BrMe2Si substituents are highly reactive to nucleophilic reagents such as water. The high reactivity of the Si-Br bonds suggested that these substituents could react with hydroxyl groups on the surface of partially dehydroxylated silica, forming covalently immobilized metallocene catalysts. This dissertation concerns the synthesis of electrophile-functionalized zirconocene dihalide complexes and the use of functionalized zirconocene dihalides as precursors to silica-supported metallocene olefin polymerization catalysts.
Our first objective was to extend the metallocene "functionalization" chemistry to obtain substituents bearing more than one electrophilic bond. The reactivities of Me3Sn and Ph2MeSi substituents were explored in detail. (Me3Sn)2C5H4 combined with CpZrCl3 in toluene to afford (h5-Me3Sn-C5H4)CpZrCl2 (A). Reactions of A with electrophiles (E-X = Cl2B-Cl, I-Cl, and I-I) afforded (ï ¨5-XMe2Sn-C5H4)CpZrCl2 (and E-Me) cleanly. The reaction of A with BBr3 afforded either (ï ¨5-BrMe2Sn-C5H4)CpZrBr2 (25 ï °C, 10 min) or (ï ¨5-Br2MeSn-C5H4)CpZrBr2 (25 ï °C, 15 h). Ph2MeSi-C5H4Li combined with ZrCl4â ¢2THF to afford (h5-Ph2MeSi-C5H4)2ZrCl2 (B). The reaction of B with BCl3 led to incomplete cleavage of the Ph-Si bonds, however treatment of B with BBr3 afforded (h5-Br2MeSi-C5H4)2ZrBr2 (C) efficiently. The Sn-X bonds of the stannylated metallocenes were however relatively unreactive toward water and were excluded as candidates precursors for supported metallocene catalysts. X-ray crystal structures of (h5-ClMe2Sn-C5H4)CpZrCl2⠢½toluene, (h5-Br2MeSn-C5H4)CpZrBr2â ¢THF, B, and C were obtained.
The functionalized metallocene C reacts with water to afford an oligosiloxane-supported zirconocene dibromide. Combinations of solution 1H NMR, solid state CPMAS 13C NMR, and solid state CPMAS 29Si NMR spectroscopy suggested a stereoregular structure in which the metallocene units have local Cs (meso) symmetry. Although only sparingly soluble, the oligomeric substance showed activity for homogeneous ethylene polymerization (toluene solution, MAO cocatalyst, Al:Zr = 5000, 50 ï °C) similar to Cp2ZrCl2.
Supported metallocene olefin polymerization catalysts were prepared by combining a functionalized metallocene precursor (Cp2ZrBr2 bearing either BrMe2Si or Br2MeSi groups) and partially dehydroxylated silica. Ethylene polymerization activity of the resulting catalysts was examined as a function of the precursor structure (number of reactive "tethering" groups, one vs. two Si-Br bonds per tethering group) and the immobilization conditions (time, temperature, presence or absence of NEt3 promoter). The activities of the immobilized zirconocene catalysts decreased and the stabilities increased with increasing number of tethers. The immobilized catalyst prepared from (ï ¨5-Br2MeSi-C5H4)2ZrBr2, which is assumed to form two "double-tethers" to silica, was significantly more active than the catalyst prepared from [ï ¨5-1,3-(BrMe2Si)2C5H3]2ZrBr2, which is assumed to form four "single-tethers" to silica. Catalyst leaching was observed in all the immobilized zirconocene catalysts. The use of NEt3 in the immobilization reaction enabled more metallocene to be supported, but the resulting activity was lower.
The dissertation also includes model studies on the immobilization reaction and the stability of the Si-O-Si bonds. The reaction of C with tBuMe2SiOH results in the formation of Si-O-Si bonds; addition of NEt3 results in further reaction to afford Si-O-Zr bonds. The reaction of Reaction of Me3Si-O-SiMe3 with MAO showed that Si-O-Si bonds can be cleaved under the conditions of our polymerization reactions.Ph. D.
36
Guo, Jianping. "Synthesis, structure and characterization of long distance electrostatic force and hydrogen bond supramolecular polymers synthesis, structure and characterization of bis[2,4-di(pyridyl)-1,3,5-triazapenta-dienato] metal complexes". HKBU Institutional Repository, 2004. http://repository.hkbu.edu.hk/etd_ra/506.
Pełny tekst źródła
37
Eichenseher, Sandra. "Rhenium-containing phosphines and phosphine oxides new design strategies for highly active and, or enantioselective organometallic catalysts for organic synthesis /". [S.l. : s.n.], 2005. http://deposit.ddb.de/cgi-bin/dokserv?idn=975727532.
Pełny tekst źródła
38
Ghatak, K. "Activation of small molecules via organometallic pincer catalysts and small rhodium clusters (pure and doped): a density functional theory approach". Thesis(Ph.D.), CSIR-National Chemical Laboratory, Pune, 2015. http://dspace.ncl.res.in:8080/xmlui/handle/20.500.12252/2044.
Pełny tekst źródła
39
Schwarz, Andrew Douglas. "Sulfonamide supported catalysts for the ring opening polymerisation of cyclic esters". Thesis, University of Oxford, 2010. http://ora.ox.ac.uk/objects/uuid:74918e6d-524b-404a-a3e7-c1c34987f4f4.
Pełny tekst źródłaStreszczenie:
This Thesis describes the synthesis and characterisation of sulfonamide supported titanium, zirconium and aluminium complexes and their use as ring opening polymerisation catalysts for ε-caprolactone and rac-lactide. Chapter 1 introduces polyester use, development and characterisation in general. Metal catalysed ring opening polymerisation of cyclic esters is considered in a literature review of the field. Titanium, zirconium and aluminium complexes supported by polydentate sulfonamide ligands are also discussed. Chapter 2 describes the synthesis and characterisation of new sulfonamide supported titanium amide, isopropoxide and zirconium isopropoxide complexes. Their application as catalysts for the ring opening polymerisation of ε-caprolactone and rac-lactide is discussed and compared with known zirconium isopropoxide complexes supported by bis(phenolate) amine ligands. Chapter 3 describes the synthesis and characterisation of Cs symmetric titanium amide and alkoxide complexes supported by dianionic, tri- and tetradentate sulfonamide ligands. Zirconium alkyl and amide complexes supported by C3- symmetric trianionic ‘tren’ type ligands bearing three different sulfonamide groups are also presented. The application of these complexes for the ring opening polymerisation of ε-caprolactone and rac-lactide is described and compared with the complexes presented in Chapter 2. Chapter 4 provides an overview of the synthesis and characterisation of aluminium alkoxide and alkyl complexes supported by dianionic, tri- and tetradentate sulfonamide ligands. Solution state behaviour and solid state structures are presented and discussed. An assessment of these complexes for the ring opening polymerisation of rac-lactide is presented. Chapter 5 presents full experimental procedures and characterisation data for the new complexes reported. CD Appendix contains .cif files for all new crystallographically characterised complexes described, and additional polymerisation graphs.
40
Shin, Seunghoon. "Part I. Water-soluble organometallic catalysts for asymmetric reactions in aqueous media ; Part II. Silylstannylative cyclization of unsaturated substrates catalyzed by Palladium Complex /". The Ohio State University, 2001. http://rave.ohiolink.edu/etdc/view?acc_num=osu1486474078048077.
Pełny tekst źródła
41
Clavadetscher, Jessica Veronica. "Transition metal catalysis : a new paradigm in bioorthogonal drug activation". Thesis, University of Edinburgh, 2017. http://hdl.handle.net/1842/29580.
Pełny tekst źródłaStreszczenie:
Powerful tools have emerged in the past few years to allow the sensing, imaging and modulation of biological processes in living systems. Bioorthogonal organometallic reactions are transformations catalysed by transition metals, which are compatible within a biological environment. Palladium-mediated cross-coupling and decaging reactions, for example, have been successfully applied to catalyse non-natural chemical transformations within a biological milieu. Up until now, copper-catalysed cycloaddition reactions have been used extensively for the conjugation, immobilisation, and purification of biomolecules, but their further application in vivo has been limited by the inherent toxicity of copper. Herein, different transition metal catalysts were designed and applied in cellular and in vivo manipulations. Polymeric solid supports were functionalised with palladium nanoparticles and used as biocompatible, heterogeneous catalysts in selective decaging and cross-coupling reactions to activate fluorescent probes and synthesise cytotoxic anticancer drugs in situ. In order to gain tumour selectively, targeting functionalities were incorporated into the particles to allow the spatial control of the selective activation of labelling probes. The simultaneous synthesis of two different anticancer agents intracellularly, by two totally different mechanisms (in situ synthesis and decaging), is reported. The cellular toxicity of copper was addressed by entrapping copper nanoparticles on a polymeric solid support, allowing the activation of labelling probes, as well as the synthesis of an anticancer agent from two benign components through the well-known copper catalysed azide-alkyne cycloaddition. The biocompatibility of the copper catalysts in vivo was shown by implantation in zebrafish embryos.
42
Miller, John Richard Anthony. "Synthesis of optically active amino-acids and some chiral compounds as intermediates to squalestatin using novel organometallic catalysts and material from the chiral pool". Thesis, University of Essex, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.302567.
Pełny tekst źródła
43
Lescouet, Tristan. "Conception et fonctionnalisation de MOFs pour le greffage et l'encapsulation de complexe organométallique". Phd thesis, Université Claude Bernard - Lyon I, 2012. http://tel.archives-ouvertes.fr/tel-00975367.
Pełny tekst źródłaStreszczenie:
Les Metal-Organic Frameworks résultent de l'organisation de clusters métalliques et demolécules organiques chélatantes qui forment un réseau cristallin poreux. Leur découverte apermis des avancées majeures dans le domaine du stockage et de la séparation des gaz.Malheureusement la faible stabilité et l'acidité modérée de ces matériaux ne les rendent quepeu compétitifs par rapport aux zéolites dans le domaine du raffinage ou de la dépollution. Ils'agit d'explorer, avec ces matériaux, de nouvelles applications catalytiques en tirant partie deleur principale qualité : leur modularité. En effet le large choix de métaux, de ligands, ainsique la post fonctionnalisation de ces derniers permet la synthèse contrôlée de matériauxpossédant des propriétés de flexibilité, de confinement ainsi qu'un environnement chimiquesimilaire à celui des sites actifs des enzymes. Ce travail s'inspire du procédé catalytique desenzymes pour obtenir des MOFs hautement sélectifs en conditions douces. Nous décrivons ledéveloppement de méthodes pour encapsuler des catalyseurs organométalliques dans despores calibrés afin de modifier la sélectivité d'une réaction d'oxydation et stabiliser lecatalyseur. Quatre MOFs supportant des groupes amino ont été synthétisés afin de permettreleur post fonctionnalisation. Les propriétés de flexibilité ainsi que la distribution des sitespotentiellement actifs du MOF MIL-53 ont également été contrôlés grâce à lafonctionnalisation partielle de la structure. Enfin ces amino MOFs furent post fonctionnalisésen isocyanate en deux étapes afin d'améliorer la réactivité de la structure et de permettre legreffage de diverses amines. Ces outils pourraient permettre à court terme la conception deMOFs dont les pores ont un environnement semblable aux metalloenzymes.
44
Roussey, Arthur. "Preparation of Copper-based catalysts for the synthesis of Silicon nanowires". Thesis, Lyon 1, 2012. http://www.theses.fr/2012LYO10164.
Pełny tekst źródłaStreszczenie:
Les travaux dans cette thèse ont pour objectif la synthèse de catalyseurs (nanoparticules de cuivre) de taille contrôlée pour la synthèse de nanofils de silicium dans des conditions compatibles CMOS, c'est-à-dire en évitant l'utilisation de l'or comme catalyseur et pour des croissances basse température (<450°C). Les résultats obtenus ont permis de montrer que les techniques de chimie de surface classiquement utilisées pour la préparation de catalyseurs sur des supports 3D (silice, nitrure de titane…) sont directement applicables et transférables sur des supports 2D (wafer de silicium recouvert de films fins de SiO2, SiOx et TiN). Nous avons par exemple pu préparer des nanoparticules de cuivre de taille contrôlée (de 3 nm à 40 nm de diamètre moyen suivant les conditions expérimentales et supports). De plus, les mécanismes de formation des nanoparticules en fonction des propriétés de surface des matériaux étudiés ont été démontrés en combinant diverses techniques d'analyses de surface. La croissance de nanofils de silicium à partir de ces catalyseurs sur substrats 2D a également été réalisée avec succès dans des procédés à basse température. Il a notamment été montré l'existence d'un diamètre minimum critique à partir de laquelle la croissance basse température était possibleThe work presented in this PhD thesis aimed at the preparation of copper nanoparticles of controllable size and their utilization as catalysts for the growth of silicon nanowires in a process compatible with standard CMOS technology and at low temperature (< 450°C). The growth of silicon nanowires by Chemical Vapor Deposition (CVD) via the catalytic decomposition of a silicon precursor on metallic nanoparticles at low temperature (Vapor Solid-Solid process) was demonstrated to be possible from an oxidized Cu thin film. However, this process does not allow the control over nanowires diameter, which is controlled by the diameter of the nanoparticle of catalyst. In this PhD is presented a fully bottom-up approach to prepare copper nanoparticles of controllable size directly on a surface without the help of external stabilizer by mean of surface organometallic chemistry. First, the preparation of copper nanoparticles is demonstrated on 3D substrates (silica and titanium nitride nanoparticles), along with the fine comprehension of the formation mechanism of the nanoparticles as a function of the surface properties. Then, this methodology is transferred to planar (2D) substrates typically used in microelectronics (silicon wafers). Surface structure is demonstrated to direct the Cu nanoparticles diameter between 3 to 40 nm. The similarities between the 2D and 3D substrates are discussed. Finally, the activity of the Copper nanoparticles in the growth of Silicon nanowire is presented and it is demonstrated that in our conditions a critical diameter may exist above which the growth occurs
45
Ortiz, Cesar Gabriel. "Synthesis of 1,3,5-triaza-7-phosphaadamantane (PTA) and 3,7-diacetyl-1,3,7-triaza-5-phosphabicyclo[3.3.1]nonane (DAPTA) complexes and the development of chromium salen catalysts for the copolymerization of CO2 and epoxides". Texas A&M University, 2004. http://hdl.handle.net/1969.1/359.
Pełny tekst źródłaStreszczenie:
Two main areas are considered in this manuscript. The first describes the synthesis of group 10 metal complexes incorporating the water-soluble 1,3,5-triaza-7-phosphaadamantane (PTA) ligand and the second deals with the preparation of Cr(salen)X catalysts for the copolymerization of CO2 and epoxides. In the first topic, the synthesis of nickel(II) and palladium(II) salicylaldiminato complexes incorporating PTA has been achieved employing two preparative routes. Upon reacting the original ethylene polymerization catalyst developed by Grubbs and coworkers (Organometallics, 1998, 17, 3149), (salicylaldiminato)Ni(Ph)PPh3, with PTA using a homogeneous methanol/toluene solvent system resulted in the formation of the PTA analogs in good yields. Alternatively, complexes of this type may be synthesized via a direct approach utilizing (TMEDA)M(CH3)2 (M = Ni, Pd), the corresponding salicylaldimine, and PTA. Polymerization reactions were attempted using the nickel-PTA complexes in a biphasic toluene/water mixture in an effort to initiate ethylene polymerization by trapping the dissociated phosphine ligand in the water layer, thereby, eliminating the need for a phosphine scavenger. Unfortunately, because of the strong binding ability of the small, donating phosphine (PTA) as compared to PPh3, dissociation did not occur at a temperature where the complexes are not subjected to decomposition. Additionally, the unexplored PTA derivative, 3,7-diacetyl-1,3,7-triaza-5-phosphabicyclo[3.3.1]nonane (DAPTA), prepared by the literature procedure, was fully characterized by NMR and X-ray analysis. DAPTA is found be similar to its parent (PTA) in coordination mode and binding strength, as supported by its representative group 6 and group 10 complexes
The second main topic involves the copolymerization of CO2 and epoxides (i.e., cyclohexene oxide (CHO)) for the formation of polycarbonate using Cr(salen)X (X = Br, OPh) catalysts with one equivalent of PR3 as the co-catalyst. The use of these catalysts and cocatalysts results in the most active chromium-based catalytic systems to date. The
. hr-1highest activities observed are on the order of 109 mol CHO consumed . mol Cr-1 using PCy3 as the co-catalyst, and is clearly seen in the in situ monitoring of copolymer formation. An advantage of these systems involves the lack of cyclic carbonate production and high CO2 incorporation (>99%) within the polymer.
46
Cavarzan, Alessandra <1983>. "Organometallic catalysis within self-assembled supramolecular structures". Doctoral thesis, Università Ca' Foscari Venezia, 2011. http://hdl.handle.net/10579/1090.
Pełny tekst źródłaStreszczenie:
The initial aim of this thesis was to substitute traditional solvents characterized by high environmental impact, with more environmentally friendly and health compatible aqueous media. This approach is relevant to recent trends in green chemistry, especially when considering industrial scale productions. The transfer in water of processes normally performed in organic solvents is accomplished by means of solubilizing agents such as surfactants, that are cheap and extensively used in several industrial processes, first of all in the formulation of detergents. The use of surfactants is of great interest in terms of “greening up” chemical processes especially because the general current method to run aqueous homogeneous and biphasic catalytic reactions is to modify catalysts with water soluble tags to make them soluble in water. This involves energy, money and time consuming synthetic procedures. Moreover the modified catalyst can display different sterics and electronics compared to the original one that may not be favorable for its performance. The use of surfactant-based nano-aggregates (micelles) falls also within an innovative research field concerning not only the possibility of switching from organic to aqueous phase, but also the tuning of the chemical reaction selectivity exploiting the tridimensional scaffold built by micelles around hydrophobic catalysts and substrates. The initial objective was then widened including a comprehensive study on the effect of supramolecular self-assembled hosts, such as micelles, in reactions mediated by organometallic catalysts. The inclusion of organometallic complexes within nanometric supramolecular aggregates would allow a fine tuning of the selectivity on the basis of shape, dimensions and affinity of substrates with the host, similarly to the interaction between a substrate and the complex peptide backbone of an enzyme. At the beginning the attention was focused on the hydration of nitriles, in order to use the aqueous medium also as reactant and avoid the co-solvent approach. The catalysts used were a series of RuII complexes and the major goal was the development of a highly active system without modifying the catalyst structure and using milder conditions than the traditional ones.
Subsequently the work continued with the application of micellar systems to the Baeyer-Villiger oxidation of cyclic ketones, extensively studied in the past in our lab in common organic solvents, but poorly studied in aqueous medium, except in its enzymatic version. This oxidation reaction presents both activity and selectivity issues: high activities are difficult to achieve especially for intrinsically less reactive cyclic six-members ring ketones, while selectivity is a general problem to overcome in oxidation. Micellar systems were tested in order to solve both challenges by virtue of the confinement of catalyst and substrates inside the supramolecular structure.
The idea was expanded to supramolecular hosts combined with organometallic complexes. The use of a self-assembling capsule was evaluated during a six-months stage in the research group of prof. Joost N.H. Reek at the Van’t Hoff Institute of Molecular Sciences, University of Amsterdam. The capsule of choice was the C-undecylcalix[4]resorcinarene hexamer, for which no examples of organometallic catalyst encapsulation has been reported so far. The objective of this part of the work was to mimic enzyme behavior developing new catalytic entities capable to address general issues like product and substrate selectivity. The initial interest focused on the formation of a supramolecular catalyst, exploiting the large cavity of this capsule in which a metal complex could be encapsulated, followed by the extension of this new system to the hydration of alkynes as a model reaction. Water is vital for the formation of the nano-capsule and this drove the attention again to hydration reactions. Compatibility with the catalytic nature of the encapsulated organometallic complex was solved.
Albeit further studies are required to optimize this unusual catalytic system and to eventually scale up the micellar processes, there are some fundamental concepts that have been proven not only to comply with environmental issues, but also towards the creation of high-performance catalysts with a new catalysis concept.L'utilizzo di nano-aggregati a base di tensioattivi (micelle) implica non soltanto la possibilità di passare da mezzo organico a mezzo acquoso, ma anche la modulazione della selettività di una reazione sfruttando la struttura tridimensionale costruita dalla micella stessa attorno a catalizzatori e substrati idrofobi. Questa tesi include uno studio completo sull'effetto di 'hosts' supramolecolari auto-assemblanti, come le micelle, in reazioni mediate da catalizzatori organometallici. L'inclusione di complessi organometallici all'interno di sistemi micellari ha permesso di variare l'attività e la selettività (sulla base di forma, dimensione e affinità del substrato con l'host supramolecolare) di reazioni com el'idratazione di nitrili e l'ossidazione di Baeyer-Villiger di chetoni ciclici. L'idea è stata poi estesa ad una capsula supramolecolare per la quale non era mai stata riportata l'inclusione di complessi organometallici. E' stato così sviluppato un nuovo catalizzatore supramolecolare, incapsulando un complesso di oro all'interno di questo host. Successivamente questo sistema è stato testato nell'idratazione di alchini come reazione modello, osservando un'insolita selettività sia di prodotto sia di substrato. Nonostante siano richiesti ulteriori studi per ottimizzare questi sistemi catalitici innovativi, in questa tesi sono stati dimostrati alcuni concetti fondamentali che riguardano non soltanto la realizzazione di processi ecocompatibili, ma anche la creazione di catalizzatori altamente performanti nell'ottica di sviluppare una nuova visione della catalisi.
47
Debuissy, Thibaud. "Development of new polyesters by organometallic and enzymatic catalysis". Thesis, Strasbourg, 2017. http://www.theses.fr/2017STRAE003/document.
Pełny tekst źródłaStreszczenie:
Dans un contexte du développement durable, de nouvelles architectures macromoléculaires biosourcées ont été synthétisées à partir de synthons (diacides et diols) pouvant être obtenus par voies fermentaires à partir de sources carbonées issues de la biomasse. Dans un premier temps, différents copolyesters aliphatiques ont été synthétisés en masse, à l’aide d’un catalyseur organométallique à base de titane, à partir de diacides (acides succinique et adipique) et de diols (1,3-propanediol, 1,4-butanediol et 2,3-butanediol) courts. Dans un deuxième temps, des architectures macromoléculaires similaires ont été obtenues par catalyse enzymatique en solution à l’aide de la lipase B de Candida antarctica. L’influence de la longueur et de la structure des monomères sur leur réactivité en présence de la lipase a été particulièrement étudiée. Dans un troisième et dernier temps, des architectures macromoléculaires à base d’oligomères hydroxytéléchéliques d’un polyester bactérien : le poly((R)-3-hydroxybutyrate) (PHB)tels que des poly(ester-éther-uréthane)s et des copolyesters ont été obtenues soit par couplage de chaîne à l’aide d’un diisocyanate, ou par transestérification organométallique et enzymatique. Ces études ont permis d’analyser en détail l’effet de l’addition des synthons biosourcés dans les architectures macromoléculaires et notamment sur la structure cristalline, la stabilité thermique et les propriétés thermiques et optiques de ces polymères. De plus, le grand potentiel de la catalyse enzymatique pour la synthèse de polyesters et celui de l’utilisation d’oligomères de PHB pour l’élaboration de nouveaux matériaux performants ont pu être largement démontrésIn the context of sustainable development, new biobased and aliphatic macromolecular architectures were synthesized from building blocks that can be obtained by fermentation routes using carbon sources from the biomass. First, several aliphatic copolyesters were synthesized in bulk from short dicarboxylic acids (such as succinic and adipic acids) and diols (such as 1,3-propanediol, 1,4-butanediol and 2,3-butanediol) by organometallic catalysis using an effective titanium-based catalyst. In a second time, similar macromolecular architectures were synthesized by an enzymatic process in solution using Candida antarctica lipase B as catalyst. The influence of the alkyl chain length and the structure of monomers on their reactivity toward the lipase were particularly discussed. In the third and last part, new macromolecular architectures based on hydroxytelechelic oligomers of a bacterial polyester: poly((R)-3-hydroxybutyrate) (PHB), such as poly(ester-ether-urethane)s and copolyesters, were obtained by either chain-coupling using a diisocyanate, or organometallic and enzymatic transesterification, respectively.These studies permitted to determine a close relationship between the effect of the building blocks structure integrated in the final macromolecular architectures and the intrinsic properties, such as the crystalline structure, the thermal stability and the thermal and optical properties, of these polymers. In addition, the great potential of the lipase-catalyzed synthesis of polyesters and the use of PHB oligomers for developing new high performance materials has been clearly established
48
Lambert, Romain. "Nouveaux copolymères et nanostructures dérivés de liquides ioniques à base d'imidazoliums : applications en catalyse et comme additifs conducteurs ioniques". Thesis, Bordeaux, 2016. http://www.theses.fr/2016BORD0306/document.
Pełny tekst źródłaStreszczenie:
Des poly(liquides ioniques) (PILs) arrangés sous la forme de copolymères statistiques,de nanoparticules à chaine unique ou bien sous la forme de copolymères à blocs autoassemblés ont été employés comme précurseurs de carbènes N-hétérocycliques (NHC)s à des fins de catalyses organiques ou organométalliques. L’introduction d’anions acétate dans des unités PIL dérivés d’imidazolium permet la génération in situ de NHCs actifs en catalyse. Les nanoparticules composées d’une chaine unique polymère repliée sur elle-même (SCNP) ont été spécialement conçues selon deux stratégies impliquant, d’une part, une réaction d’autoquaternisation entre groupements fonctionnels antagonistes portés par la chaine et, d’autre part, une réaction de complexation organométallique à l’aide d’un sel de palladium. Dans lesdeux cas, les chaines polymères ont été obtenues par polymérisation contrôlée (méthode RAFT). Les copolymères à blocs amphiphiles comportant un bloc PIL fonctionnalisé par du palladium ont été synthétisés par polymérisation RAFT et auto-assemblés dans l’eau sous forme de micelles.Un effet de confinement des sites catalytiques a clairement été démontré à travers des réactions de catalyse pour les couplages de Suzuki et de Heck dans l’eau, avec un gain cinétique très net par rapport à des homologues non micellisés, en plus d’une grande facilité de recyclage de ces supports micellaires.Enfin, des copolymères à blocs à base de PIL-benzimidazolium à contre anion bis(trifluoromethane)-sulfonylimide de lithium ont été développés comme agents dopants conducteurs ioniques de matrices structurantes PS-b-PEO. Des mélanges configurés en films minces avec une quantité minimale d’agent dopant ont conduit dans certaines conditions à des valeurs optimales de conductivité ionique grâce à une nano structuration des films à longue distancePoly(ionic liquid)s (PILs) in the form of random copolymers, single chain nanoparticles(SCNPs), or self assembled block copolymers have been used as N-heterocyclic carbenes(NHCs) precursors for the purpose of organic and organometallic catalysis. Introducing acetate derivative counter anion in imidazolium based PIL units enable in situ generation of catalyticallyactive NHC. SCNPs have been specially designed along two strategies including, firstly, a self quaternization reaction involving two antagonists groups supported on to the polymer chain and,secondly, an organometallic complexation featuring palladium salt. Both polymeric precursors were obtained using RAFT as controlled polymerization method. Amphiphilic block copolymers composed of a PIL block functionalized by palladium have been synthesized by RAFT and self-assembled in water, leading to micellar structures. Confinement effect has been demonstrated through Suzuki and Heck coupling in water showing kinetic gain compared to molecular homologue in addition to an easier recycling method.Finally, PIL-benzimidazolium based block copolymers with lithium bis(trifluoromethane)-sulfonylimide anion have been developed as ionic conductor doping agent for PS-PEO matrix. Thin films blends with minimum doping agent amount led to optimum ionic conductivity owing tolong range order
49
Ayadi, Marwa. "RÉACTIONS SÉLECTIVES DES ADDUITS ALLYLIQUES DE MORITA-BAYLIS-HILLMAN CATALYSÉES PAR LES SELS MÉTALLIQUES". Thesis, Montpellier, Ecole nationale supérieure de chimie, 2017. http://www.theses.fr/2017ENCM0013/document.
Pełny tekst źródłaStreszczenie:
Le développement de nouvelles méthodes efficaces et générales pour la création de liaison C-C et C-hétéroatome constitue un des domaines les plus actifs de la chimie organique actuelle. Notre thèse s’inscrit dans cette lignée. Il vise au développement d’une réaction d’alkylation allylique des adduits de Morita-Baylis-Hillman, catalysée par le fer(III), avec divers types de nucléophiles. En effet, les adduits de Morita-Baylis-Hillman ont permis, selon la nature des substrats et les conditions opératoires, d’accéder sélectivement à diverses familles de composés de plus en plus complexes dont certains sont doués d’activités biologiques intéressantesThe development of new efficient and general methods for the creation of C-C bond and C-heteroatom is one of the most active areas of current organic chemistry.Our thesis is part of this lineage. It aims at the development of an allylic alkylation reaction of the Morita-Baylis-Hillman adducts, catalyzed by iron(III), with various types of nucleophiles. In fact, depending on the nature of the substrates and the operating conditions, the adducts of Morita-Baylis-Hillman have enabled selective access to various families of increasingly complex compounds, some of which are endowed with interesting biological activities
50
Wong, Hau To. "Solvent nanofiltration for organometallic catalysed reactions". Thesis, Imperial College London, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.429120.
Pełny tekst źródła