Дисертації з теми "Au-catalyzed"
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Ma, Ruoyu. "Chiral NHC-Au(I) Catalyzed Enantioselective Reactions." Miami University / OhioLINK, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=miami1585432603722902.
Повний текст джерелаYaguchi, Momo. "The Effect of Lattice Strain in Electrochemical Oxidations Catalyzed by Au-PdPt Core-shell Octahedral Nanoparticles." Thesis, Boston College, 2012. http://hdl.handle.net/2345/2928.
Повний текст джерелаPt-based alloy and core-shell nanoparticles have been intensively studied to regulate its size and shape. It has known that these nanoparticles show enhanced catalytic activity in various important fields such as heterogeneous catalysis, and electrochemical energy storage including fuel cells and metal-air batteries. Here, we report a facile hydrothermal synthesis of sub-10 nm PdPt alloy and sub-20 nm Au@PdPt core-shell structures. By using a mild reducing agent in aqueous solution, metal precursors are co-reduced. Specific gases are introduced during the synthesis to optimize the reaction conditions. The PdPt alloy and Au@PdPt core-shell nanostructures were characterized and confirmed by TEM, HRTEM, EDS, ICP-OES and XRD. The resulting PdPt and Au@PdPt particles are monodispersed single crystalline and octahedral shape enclosed by (111) facets. The electrocatalytic activity for the oxidation of formic acid was tested. It was found that the catalytic activity toward the formic acid oxidation of Au@PdPt core-shell particles were much higher than those of PdPt alloy particles. In addition, Pt-rich compositions were the most active in both PdPt alloy and Au@PdPt core-shell nanoparticles. Further studies on thinner alloy-shell core-shell nanoparticles reveal that there is a volcano-curve relationship between the lattice strain strength related to alloy-shell thickness and the catalytic performance. It is proposed that there are three key parameters that can determine the catalytic activity: the alloy composition, the presence of the gold core, and the thickness of alloy-shell
Thesis (MS) — Boston College, 2012
Submitted to: Boston College. Graduate School of Arts and Sciences
Discipline: Chemistry
Cera, Gianpiero <1985>. "Au(I) Catalyzed Manipulation of Propargylic Alcohols: A New Route Towards the Synthesis of Indole Alkaloids." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2014. http://amsdottorato.unibo.it/6417/1/Cera_Gianpiero_Tesi-1.pdf.
Повний текст джерелаIn questo lavoro di tesi abbiamo presentato diversi aspetti riguardanti la possibilità di utilizzare alcoli propargilici come precursori aciclici nello sviluppo di nuove reazioni a cascata stereoselettive [Au(I)] catalizzate per la sintesi di architetture indoliche altamente funzionalizzate. Alcoli propargilici su base indolica di tipo 1, sono stati utilizzati per sviluppare un processo a cascata per la sintesi di una nuova classe di indoline tetra cicliche, diidropiranilindoline A e furoindoline B. Un protocollo enantioselettivo è stato successivamente studiato per la sintesi di tali strutture con buone rese ed elevati eccessi enantiomerici. Diversi alcoli propargilici sono stati studiati nello sviluppare reazioni a cascata [Au(I)] catalizzate per la sintesi e funzionalizzazione di anelli indolici. Precursori su base anilinica di tipo 2, si sono rivelati essere precursori di eccellenza per la sintesi di [1,2-a]-azepino-indoli di tipo C. Nel descrivere quest’ultima reattività abbiamo riportato evidenze sperimentali di una nuova specie [Au(I)]-carbenica in grado di dirigere la chiusura dell’anello a sette termini in maniera altamente chemoselettiva. La flessibilità chimica degli alcoli propargilici è stata infine studiata cambiata la natura dell’intorno chimico con differenti gruppi N-alchilati in precursori di tipo 3. Utilizzando come catena un alcol primario, la selettività della reazione si è dimostrata completamente rivolta verso la sintesi della classe dei [4,3-a]-ossazino-indoli D, mentre utilizzando alcoli allilici abbiamo riportato il primo esempio di sintesi e funzionalizzazione enantioselettiva [Au(I)]catalizzata, di questa classe di molecole (D*). Concludendo, in questo lavoro abbiamo stabilito gli alcoli propargilici, essere precursori d’eccezione in reazioni a cascata Au(I) catalizzate riportando nuovi strumenti sintetici per la sintesi stereo selettiva di architetture indoliche ed indoliniche estremamente complesse.
Cera, Gianpiero <1985>. "Au(I) Catalyzed Manipulation of Propargylic Alcohols: A New Route Towards the Synthesis of Indole Alkaloids." Doctoral thesis, Alma Mater Studiorum - Università di Bologna, 2014. http://amsdottorato.unibo.it/6417/.
Повний текст джерелаIn questo lavoro di tesi abbiamo presentato diversi aspetti riguardanti la possibilità di utilizzare alcoli propargilici come precursori aciclici nello sviluppo di nuove reazioni a cascata stereoselettive [Au(I)] catalizzate per la sintesi di architetture indoliche altamente funzionalizzate. Alcoli propargilici su base indolica di tipo 1, sono stati utilizzati per sviluppare un processo a cascata per la sintesi di una nuova classe di indoline tetra cicliche, diidropiranilindoline A e furoindoline B. Un protocollo enantioselettivo è stato successivamente studiato per la sintesi di tali strutture con buone rese ed elevati eccessi enantiomerici. Diversi alcoli propargilici sono stati studiati nello sviluppare reazioni a cascata [Au(I)] catalizzate per la sintesi e funzionalizzazione di anelli indolici. Precursori su base anilinica di tipo 2, si sono rivelati essere precursori di eccellenza per la sintesi di [1,2-a]-azepino-indoli di tipo C. Nel descrivere quest’ultima reattività abbiamo riportato evidenze sperimentali di una nuova specie [Au(I)]-carbenica in grado di dirigere la chiusura dell’anello a sette termini in maniera altamente chemoselettiva. La flessibilità chimica degli alcoli propargilici è stata infine studiata cambiata la natura dell’intorno chimico con differenti gruppi N-alchilati in precursori di tipo 3. Utilizzando come catena un alcol primario, la selettività della reazione si è dimostrata completamente rivolta verso la sintesi della classe dei [4,3-a]-ossazino-indoli D, mentre utilizzando alcoli allilici abbiamo riportato il primo esempio di sintesi e funzionalizzazione enantioselettiva [Au(I)]catalizzata, di questa classe di molecole (D*). Concludendo, in questo lavoro abbiamo stabilito gli alcoli propargilici, essere precursori d’eccezione in reazioni a cascata Au(I) catalizzate riportando nuovi strumenti sintetici per la sintesi stereo selettiva di architetture indoliche ed indoliniche estremamente complesse.
Charpenay, Mélanie. "Fenestradiènes et cyclooctatriènes : synthèse directe par réaction en cascade palladocatalysée." Phd thesis, Université de Strasbourg, 2012. http://tel.archives-ouvertes.fr/tel-00836869.
Повний текст джерелаZhang, Man. "Design, synthesis, and evaluation of bioactive molecules; Chiral polyvinylpyrrolidones supported Cu/Au nanoclusters catalyzed cyclization of 5-substituted nona-1,8-dien-5-ols." Diss., Kansas State University, 2017. http://hdl.handle.net/2097/35470.
Повний текст джерелаDepartment of Chemistry
Duy H. Hua
Small molecules are of great importance in drug discovery currently. The first three chapters discussed the design, synthesis and bio-evaluation of three different classes of small molecules and exploration of their biological targets. Triacsin C analogs were designed as long chain fatty acyl-CoA synthetase (ACSL) inhibitors for attenuating ischemia and reperfusion (I/R) injury. Oxadiazole derivatives were designed as T-type calcium channel inhibitors, which have potential application in the treatment of seizure and epilepsy. Tricyclic pyrone derivatives were reported as anti-Alzheimer lead compounds in previous research done by the Hua group. TP70 and CP2 were synthesized to explore their pharmacokinetics properties. Chapter 4 described chiral-substituted poly-N-vinylpyrrolidones (CSPVP) supported Cu/Au nanoclusters mediation of cyclization reaction of 5-substituted nona-1,8-dien-5-ols. A five-member cyclized lactone possessing a stereogenic tetrasubstituted carbon center was formed in a one-step Cu/Au nanoclusters-hydrogen peroxide oxidation reaction. This developed a novel and simple method to synthesize tetrasubstituted carbon stereogenic center. Drawbacks of the method in my initial study were low reaction yield and moderate enantioselectivity. The chemical yield and enantioselectivity have been significantly improved by introducing bulkier substitution in C3 and C4 positions of CSPVP according to the updates of ongoing research.
Li, Jihui. "Copper-Catalyzed Domino C-N Bond Formation for Synthesis of N-Containing Compounds (Benzimidazoles, Imidazoles, and Guanidines) - Approach toward Total Synthesis of Natural Product Raputindoles." Thesis, Paris 11, 2013. http://www.theses.fr/2013PA112130.
Повний текст джерелаThis thesis consists in three parts: bibliographic background, copper-catalyzed reactions for synthesis of N-containing compounds, approach to the synthesis of raputindoles.The first part introduces the domino reactions and their applications, then, copper-mediated reactions for construction of C-N bond formation are reviewed including Ullmann, Goldberg and Chan-Lam coupling, oxidative C-H activation/C-N formation, insertion of nitrenes and carbenoids, and hydroamination of multi-C-C bonds. This can be used as guides to design domino reaction. Following these copper-mediated single C-N bond formation reactions, recent developments of copper-catalyzed domino reactions for synthesis of heterocycles are described.The second part can be divided into three sections: 1) synthesis of benzimidazoles, 2) synthesis of imidazoles and 3) synthesis of guanidines. Each section summarizes the existing methods used for their synthesis. Following it, our synthetic work involving copper-catalyzed C-N bond formation domino reactions is discussed in detail. Our objectives include the synthesis of benzimidazoles through copper-catalyzed sequential reaction of benzamidines and boronic acids, synthesis of imidazoles via copper-catalyzed domino reaction of benzamidines and acetylenes, and synthesis of guanidines and 2-aminobenzimidazoles by Cu-catalyzed three-component reaction of cyanamides, boronic acids and amines. These copper-catalyzed domino reactions show high efficiencies from readily available and simple starting materials.The last part is about the total synthesis of raputindoles. The structure and bioactivities of raputindoles and key reactions for the total synthesis of raputindoles are introduced first, the synthetic strategies are then proposed on basis of relative synthetic methods. The key reactions we use for the synthesis of raputindoles are iridium catalyzed [3+2] annulation of o-formylarylboronic acids and 1,3-dienes, Leimgruber-Batcho indole synthesis, transition-metal catalyzed SN2 substitution and alkylborylation-protondeborylation. According to the three strategies we proposed, lots of relative reactions were investigated. The results show that it is possible to synthesize the raputindole molecules based on the iridium catalyzed [3+2] annulation of 2-formylarylboronic acids and 1,3-dienes
Gomes, Umesh Prasad. "Catalyst-assisted and catalyst-free growth of III-V semiconductor nanowires." Doctoral thesis, Scuola Normale Superiore, 2017. http://hdl.handle.net/11384/85884.
Повний текст джерелаZhou, Edouard. "Nouveaux systèmes catalytiques appliqués aux formations de liaisons C—C par couplage croisé catalysé par des sels de fer : applications, mécanismes." Thesis, Paris Sciences et Lettres (ComUE), 2018. http://www.theses.fr/2018PSLEC008.
Повний текст джерелаJabeen, Fauzia. "III-V semiconducting nanowires by molecular beam epitaxy." Doctoral thesis, Università degli studi di Trieste, 2009. http://hdl.handle.net/10077/3097.
Повний текст джерелаThis thesis is devoted to the study of the growth of III-V nanowires (NWs) by catalyst assisted and catalyst free molecular beam epitaxy (MBE). The nanostructures have been routinely characterized by scanning electron microscopy (SEM) and, to a minor extent by transmission electron microscopy (TEM). X-ray photoemission spectroscopy (XPS), scanning photoemission microscopy (SPEM), extended X-ray absrorption fi ne structure analysis (EXAFS), photoluminescence (PL) and trans- port measurements have given an important contribution on specifi c topics. The first section of this thesis reports on GaAs, InAs, and InGaAs NWs growth by Au assisted MBE. A substrate treatment is proposed that improves uniformity in the NWS morphology. Thanks to a careful statistical analysis of the NWs shape and dimensions as a function of growth temperature and duration, evidence is found of radial growth of the NWs taking place together with the axial growth at the tip. This eff ect is interpreted in term of temperature dependent diff usion length of the cations on the NWs lateral surface. The control of the NWs radial growth allowed to grow core shell InGaAs/GaAs NWs, displaying superior optical quality. A new procedure is proposed to protect NWs surface from air exposure. This procedure allowed to perform ex-situ SPEM studies of electronic properties of the NWs. The second part of this thesis is devoted to Au-free NWs growth. GaAs and InAs NWs were successfully grown for the first time using Mn as catalyst. Incorporation of Mn in the NW is studied using EXAFS technique. It is shown that Mn atoms are incorporated in the body of GaAs NWs. Use of low growth temperature is suggested in order to improve the Mn incorporation inside GaAs NWs and obtain NWs with magnetic properties. Finally, growth of GaAs and InAs NWs on cleaved Si subtrate is demonstrated without the use of any outside metal catalyst. Two kinds of nanowires have been obtained. The experimental findings suggest that the two types of nanowires grow after di fferent growth processes.
Questa tesi e' dedicata allo studio della crescita di nanofili di semiconduttori III- V tramite epitassia da fasci molecolari (MBE) assistita da catalizzatore e senza l'uso di catalizzatori. Le nanostrutture sono state caratterizzate sistematicamente tramite microscopia elettronica a scansione (SEM), e in maniera minore microscopia elettronica in trasmissione (TEM). Altre tecniche come la spettroscopia di fotoemissione da raggi x (XPS), la microscopia da fotoemissione in scansione (SPEM), la spettroscopia di assorbimento x (in particolare la extended X-ray absorpition fine structure analysis (EXAFS)) la fotoluminescenza (PL), e il trasporto elettrico hanno dato importanti contributi su problematiche specifiche. La prima parte di questa tesi riguarda la crescita di nanofili di GaAs, InAs e InGaAs tramite MBE assistita da oro. Viene proposto un trattamento del substrato che migliora nettamente l'omogeneita' morfologica dei nanofili. Grazie ad un'attenta analisi statistica della forma e delle dimensioni dei nanofili in funzione della temperatura e del tempo di crescita e' stata dimostrata la crescita radiale dei nanofili, che avviene insieme alla crescita assiale che ha luogo alla punta del nanofilo. Le osservazioni sperimentali sono state interpretate in termini di dipendenza dalla temperatura della lunghezza di diffusione dei cationi sulle super ci laterali dei nanofili. Il controllo della crescita radiale ha permesso di crescere nanofili di InGaAs/GaAs core shell, costituiti cioe' da una anima centrale di InGaAs (core) e uno strato esterno di GaAs (shell) , che hanno dimostrato eccellente qualita' ottica. Viene quindi proposta una nuova procedura per proteggere la super ficie dei nanofili durante l'esposizione all'aria. Grazie a questa e' stato possibile realizzare ex-situ uno studio SPEM delle proprieta' elettroniche dei nanofili. La seconda parte della tesi riguarda la crescita di nanofili senza l'uso di oro. Viene per la prima volta dimostrata la possibilita' di crescere nanofili di GaAs e InAs usando il manganese come catalizzatore. L'incorporazione del Mn come impurezza nei nanofili e' stata studiata tramite EXAFS. Le misure hanno dimostrato che atomi di Mn sono effettivamente incorporate nel corpo dei nano fili. La crescita delle nanostrutture a temperatura piu' bassa potrebbe migliorare qualitativamente l'incorporazione del Mn e permettere la crescita di nanofili con proprieta' magnetiche. Viene in fine dimostrata la crescita di nanofili di GaAs e di InAs senza l'utilizzo di materiali diversi da quelli costituenti il semiconduttore. Tale risultato e' ottenuto su superfici sfaldate di silicio. Sono state osservate nanostrutture di due tipi, che sulla base dei dati sperimentali sembrano essere dovuti a due diversi meccanismi di crescita.
XXI Ciclo
1977
Craft, Derek T. "Palladium and Gold-Catalyzed transannular [4+3] cycloaddition reactions: Application to the ABCD carbon framework of Cortistatin A. A short synthesis of S-(+)-Siphonodiol. New chiral Au(I) N-heterocyclic carbene complexes and their use in intramolecular c." Oxford, Ohio : Miami University, 2010. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=miami1272036117.
Повний текст джерелаLyu, Ye. "Cobalt-catalyzed Hydroelementation Reactions." Thesis, Sorbonne université, 2019. http://www.theses.fr/2019SORUS611.
Повний текст джерелаThis thesis was focused on well-defined low-valent cobalt complexes HCo(PMe3)4/HCoN2(PPh3)3, the bench stable family Cp*Co(III) of complexes and their applications in R–H activation (R = B, C, Si). First, we successfully used the HCo(PMe3)4 complex to catalyze regio- and stereo-selective hydroboration and diboration of alkynes. In addition, we exploited the HCo(PMe3)4 complex to catalyze silaboration of alkyne. Then, we demonstrated that the HCo(PMe3)4 complex and HCoN2(PPh3)3 complex were useful in the stereo-divergent hydrogenation of alkynes. Finally, we explored the application of the bench- stable Cp*Co(III) together with chiral additives in asymmetrical C–H bond functionalization. In addition, we conducted the elementary exploitation in synthesis of chiral Cp*Co(III) complexes
Li, Mao. "Iron(III) catalyzed asymmetric Diels-Alder reaction - Iron(II) catalyzed thia-Michael addition and aldehyde allylation reactions." Doctoral thesis, Université Laval, 2019. http://hdl.handle.net/20.500.11794/34969.
Повний текст джерелаIron catalysts are employed in three different organic transformations owing to their advantages: environmental friendliness, being less expensive and abundant on the Earth. The first project deals with asymmetric Diels-Alder reactions of α, β-unsaturated oxazolidin-2-one derivatives catalyzed by Fe¹¹¹ and a chiral bipyridine ligand. In order to obtain the optimized reaction conditions, we screened different solvents, catalyst loading, various reaction times and a variety of iron salts such as Fe(ClO₄)₂·6H₂O, Fe(ClO₄)₂·6H₂O, Fe(OTf)₃, Fe(OTf)₂, FeCl₂, FeCl₃, FeBr₃ and FeI₃. As a result, the reaction between cyclopentadiene and 3-alkenoyl-1,3-oxazolidin-2-one was carried out at –30 °C in CH₃CN in 1.5 h, with Fe(ClO₄)₃·6H₂O (2 mol%) complexed with the chiral bipyridine ligand (2.4 mol%) as catalyst, providing an excellent yield (99%) and an excellent enantiomeric excess (98%). Decreased enantioselectivities were observed for less-reactive dienes. Overall, less than 10 mol% of catalyst loading was employed. The great advantages of this project are the mild reaction temperature, very low catalyst loading, excellent yields and enantioselectivities and the applicability to a wide scope of substrates. Meanwhile, iron catalysts were used in thia-Michael additions by two different approaches. The first one is about thia-Michael additions catalyzed by Fe(OTf)₂ in EtOH at room temperature. This green method allows the thia-Michael additions to be catalyzed by a green iron salt (5 mol% of Fe(OTf)₂), a green and commonly used solvent EtOH at room temperature under ambient atmosphere. The generality of this reaction was demonstrated by applying it to different Michael acceptors, and to aromatic and aliphatic thiols. The second method is about thia-Michael additions catalyzed by Fe(OTf)₂ in 2-Me-THF, which is in agreement with the green chemistry principles by using a green Fe(OTf)₂ and a green solvent 2-Me-THF at room temperature or 50 °C under air atmosphere. The last project is about asymmetric allylation reactions catalyzed by Fe(OTf)₂ using a chiral ligand. With the study of a variety of chiral ligands, we selected 5 mol% of Fe(OTf)₂ and 6 mol% of Pybox ligand which catalyzed the reaction in good yield (70%) and 32% of ee. The utilization of 20 mol% of TMSCl is essential for the effectiveness of the reaction
Kennel, Sybille. "Synthèse de traceurs bimodaux utilisables en imagerie médicale TEP/IRM." Thesis, Bordeaux, 2015. http://www.theses.fr/2015BORD0190/document.
Повний текст джерелаToday physicians can use a wide variety of medical imaging techniques to establish early and accurate diagnosis. Nevertheless, each modality has its own advantages and drawbacks. This is why bi- or multimodality approach seems interesting. Among them, PET/MRI combination seems very promising because it can bring complementary informations. It is therefore necessary to inject to patients tracers specific to each imaging modality. This work described the synthesis of molecular platforms for MRI and PET imaging, according to 2 different strategies. The first one consisted in the synthesis of a DO3A macrocycle allowing the chelation of both gadolinium for MRI and gallium 68 for PET. The aim here is to have a bimodal probe, with a mixture of each compound. The second strategy was the preparation of a single molecule that can be simultaneously labeled by both gadolinium for MRI and fluorine 18 for PET. The final goal is to introduce onto these platforms a biomolecule in a versatile and easy way, to be able to target a specific pathophysiological process. ‘‘Click’’ chemistry seems to be an attractive methodology to achieve this goal. However, this reaction, usually catalyzed with copper is not suitable to DO3A macrocyles due to the copper affinity with those azamacrocycles. This issue has been circumvent by the use of ruthenium catalyzed ‘‘click’’ chemistry. We were then able to access to both macrocycles platforms
Arockiam, Percia Beatrice. "Ruthenium (II) catalyzed functionalization of C-H bonds : catalysis in water." Rennes 1, 2012. http://www.theses.fr/2012REN1S171.
Повний текст джерелаIn this doctoral thesis, we have shown that Ru(CO₂R)₂(p-cymene) catalyst the insitu generated from [RuCl₂(p-cymene)]₂ and KCO₂R, acts as an excellent catalyst for ortho C-H bond functionalization of arenes containing an heterocycle (pyridine, oxazoline, pyrazole) with unactivated aryl chlorides in the presence of K₂CO₃ as a base. The reactions were performed in diethyl carbonate (DEC) or in water as a solvent instead of N-methylpyrrolidone (NMP), the solvent of choice used in most of ruthenium catalyzed C-H bond transformations. The activity of these catalysts is higher in water than in other organic solvents. We have also disclosed a new catalytic system based on [RuH(codyl)₂]BF₄/2KY(KY: KOAc, KOPiv, KPI) in which the ligand Y promotes the initial cleavage of C-H bonds and the efficiency of this catalytic system depends also on the nature of both substrates involved in the reaction. The directed dehydrogenative alkenylation of N-aryl pyrazoles by styrene and alkyl acrylates catalyzed by Ru(OAc)₂(p-cymene) in the presence of a catalytic or stoichiometric amount of Cu(OAc)₂ H₂O in air is also presented and it is demonstrated that the acetic acid solvent plays a key role. A new method to generate the oxidative homocoupling of N-phenylpyrazole is shown with the Ru(OAc)₂(p-cymene) catalyst
Conyers, Ryan C. "An Investigation of Gold(I) Catalyzed Cycloaddition Reactions." Miami University / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=miami1366197923.
Повний текст джерелаKaithal, Akash. "Ruthenium (II) and Manganese (I) Catalyzed Organic Transformations via Hydrogen Transfer Reactions." Thesis, Lyon, 2020. https://n2t.net/ark:/47881/m66h4gsc.
Повний текст джерелаThe present dissertation focuses on new organic transformations enabled by hydrogen transfer reactions using Mn(I) and Ru(II) pincer complexes. The primary focus deals with the study of Mn(I) and Ru(II) complexes and their similar reactivity in hydrogen transfer reactions which includes hydrogen borrowing and reduction reactions.Chapter 1 is a general introduction of hydrogen-transfer reactions reported for Mn(I) complexes and their similar reactivity with the Ru(II) complexes that are well-established for the hydrogen-transfer reactions.Chapter 2 focuses on the utilization of MeOH as a C1 source for the synthesis of fine chemicals, pharmaceuticals and alternative fuels. The selective beta-methylation of alcohols was achieved using methanol as a C1 source. Various ruthenium complexes were investigated for this transformation and a Ru-MACHO-BH pincer complex revealed the best catalytic results. Mechanistic studies and DFT calculations confirmed that the reaction proceeds via “Hydrogen borrowing pathways” and involved metal-ligand cooperation on the ruthenium metal center.Chapter 3 also deals with the selective beta-methylation of alcohols using methanol as a C1 source. However, in this chapter, earth-abundant and air-stable manganese pincer complexes were investigated. The reactivity of Mn(I) pincer complexes with Ru(II) pincer complexes was compared. Numerous manganese pincer complexes were synthesized and checked for this process where the Mn-MACHO-iPr complex demonstrates the optimum results with high selectivity and high yield to the corresponding desired product. Chapter 4 demonstrates the formation of substituted cycloalkanes using secondary alcohols or ketones and diols as initial substrates employing Mn-MACHO-iPr complex as pre-catalyst. The reaction studies showed that the Mn-MACHO-iPr complex revealed better reactivity in comparison to the Ru-MACHO-BH complex. Various substituted cycloalkane rings such as substituted cyclopentane, cyclohexane, and cycloheptane rings were synthesized employing the Mn-MACHO-iPr complex. Mechanistic studies revealed that the reaction proceeds via “hydrogen borrowing pathways”.Chapter 5 addresses the selective deuteration of primary and aliphatic alcohols using D2O as a deuterium source. The already established Mn-MACHO-iPr complex was investigated for this transformation which showed selective deuterations of benzylic alcohols at the alpha positions and alpha and beta deuteration for aliphatic alcohols.Chapter 6 deals with the selective hydrogenation of cyclic carbonates to the analogous methanol and diols. Several manganese pincer complexes were synthesized to confirm the activity towards this transformation. Air-stable Mn-MACHO-iPr pincer complex showed the best catalytic activity with high turnover numbers and selective preparation to the corresponding methanol and diols.Chapter 7 discusses the preparation of methoxy-borane and boronate-diols via selective reduction of cyclic and linear carbonates and CO2 using pinacolborane as a reducing agent. A newly synthesized manganese pincer complex was explored for this process which revealed the high efficiency and selectivity towards this transformation
Tomakinian, Terry. "Nouvelles méthodes de synthèse de benzofuroindolines. Vers la synthèse de la phalarine." Thesis, Université Paris-Saclay (ComUE), 2015. http://www.theses.fr/2015SACLS031.
Повний текст джерелаBenzofuroindolines are a family of compounds which can be found in two regioisomeric forms: benzofuro[2,3-b]indolines or benzofuro[3,2-b]indolines. This core is present in several natural products such as bipleiophylline, voacalgine A, diazonamide A or phalarine which have been the subject of intensive efforts towards their syntheses. The postulated biogenesis is the oxidative coupling of an indole and a phenol. We developed four pathways to access these structures using the indole nucleus.The first part consisted in a direct oxidative coupling between a N-acetylindole and a phenol in presence of FeCl₃ and DDQ. This strategy showed its generality on N-acetylindoles derivatives to form in only one step the benzofuro[3,2-b]indoline core. In some cases, the benzofuro[2,3-b]indoline is obtained if the substitution in the C-2 and C-3 position is the same. In order to synthesize the phalarine, the unique natural product to possess a benzofuro[3,2-b]indoline core, we designed a C-2 arylation of an indole with a phenol using a palladium-catalyzed coupling. The cyclization steps using NIS led to the benzofuro[3,2-b]indoline core. The insertion of the missing carbon of one of the rings is under study by adding a nucleophile which contains only one carbon and a leaving group. The last strategy to access to benzofuro[3,2-b]indolines has been focused on an interrupted Fischer indolization. The reaction between benzofuran-3-ones and arylhydrazines in acidic conditions led to the desired benzofuro[3,2-b]indolines. This methodology is general and robust. Another part of the project was to achieve the Umpolung of the indole to add nucleophiles in C-3 position of the indole nucleus. N-hydroxyindoles were synthesized and the use of biaryliodonium triflate salts allowed an O-arylation reaction. The product being unstable, a [3,3] sigmatropic rearrangement can take place to afford the desired benzofuro[2,3-b]indolines
Liu, Yang. "Studies on Palladium-Catalyzed [3+2]-Annulation/Domino Reactions." Thesis, Sorbonne université, 2019. http://www.theses.fr/2019SORUS214.
Повний текст джерелаThis thesis work is consecrated to the study of palladium-catalyzed [3+2]-annulation and domino reactions. First, a new domino sequence was developed, which involves the reaction between cyclic α,β-unsaturated-γ-oxy-carbonyl derivatives and resonance-stabilized acetamides. The resulting bicyclic pyrrolidin-2-ones were generated through an intermolecular Pd-catalyzed allylation followed by an intramolecular aza-Michael reaction sequence. An asymmetric version was also achieved, obtaining up to 60% ee. A new Pd-catalyzed [allylation / aza-Michael / keto α-arylation] (ALAMAR) triple domino sequence was also accomplished, which allows the selective one-pot formation of fused tricyclic systems. Lastly, two selective and complementary domino transformations have been achieved, which allow to perform C−C/O−C or C−C/C−C [3+2]-annulations at will. These transformations occur through an intermolecular Pd-catalyzed C-allylation / intramolecular O- or C-1,4-addition sequence, respectively
Beydoun, Kassem. "Palladium catalyzed direct arylation of heteroaromatics via C-H bond activation : a green access to fine chemicals and materials." Rennes 1, 2012. http://www.theses.fr/2012REN1S174.
Повний текст джерелаAu cours de cette thèse, nous nous sommes intéressés à l'activation de liaisons CH catalysées par des complexes de palladium tels PdCl(C₃H₅)(dppb) et Pd(OAc)₂ pour la préparation de biaryles. Cette méthode est considérée comme un moyen de synthèse économique et respectueux de l'environnement comparé à d'autres types de couplages tels que les réactions de Suzuki, Stille ou Negishi. D'abord, nous avons démontré qu'il est possible d'appliquer la méthode d'activation de la liaison C-H pour l'arylation directe de formyle ou d'acétyle halothiophenes. Les produits correspondants pourraient être ensuite fonctionnalisés en raison de la présence des groupements halogène et carbonyle sur les produits obtenus. Nous avons également démontré que l'utilisation d'un solvant tel que le cyclopentyl méthyl éther (CPME), qui est considéré comme un solvant écologique par rapport aux solvants toxiques traditionnellement utilisés pour ces réactions de couplage, conduit à une variété de dérivés hétéroaromatiques arylés. Nous avons ensuite établi les conditions pour le couplage sélectif de phénols non-protégées par des bromures d'aryle en O ou en C2 du phenol. Nous avons constaté qu'un simple changement de la nature de la base utilisée dans cette réaction conduit à une sélectivité différente. Nous avons également réalisé l'arylation directe de dérivés dithienylperfluorocyclopentene via activation de liaisons C-H catalyse au palladium. Cette méthode a permis un accès plus simple à des molécules photochromiques. En outre, nous avons démontré qu'il est possible, via l'addition séquentielle des réactifs, de préparer des thiéno-ou furo-quinolines à partir de thiéno- ou furo-carboxaldéhydes et de 2-halogénoanilines. Nous avons aussi mis au point une méthode d'arylation directe catalysée par le palladium pour l'arylation d'un ligand déjà coordonné à des complexes d'iridium. Avec cette méthode, une variété de complexes possédant des propriétés physiques différentes a été obtenue
Diamante, Daria. "Transition metal-catalyzed alkoxylation and amination reactions involving propargyl or allyl derivatives." Thesis, Paris 6, 2017. http://www.theses.fr/2017PA066119/document.
Повний текст джерелаDuring the whole period of my PhD, spent in co-tutorship between Università degli Studi dell’Insubria and UPMC in Paris, I have directed my efforts towards the study of C-O and C-N bonds formation by new transition metal-catalyzed reactions.Pursuing our ongoing project on intra- and intermolecular transition metal-catalyzed amination and alkoxylation reactions involving C-H functionalization, we tried to perform two intramolecular alkoxylation procedures of carbon-carbon multiple bonds to obtain oxygenated heterocycles and one intermolecular oxidative allylic amination to accomplish nitrogen-based scaffolds.Performed at intramolecular level, transition metal-catalyzed reactions offer a versatile strategy to obtain cyclic molecules, not easily obtainable by conventional synthetic methods and starting from readily available starting materials, and represent one of the key methodologies for the progress of green and sustainable chemistry. Dealing with alkoxylation protocols, two different research lines based on transition metal catalysis applied to domino reactions were investigated. Domino processes are efficient tools to rapidly increase the molecular complexity through the formation of more than one bond in a single step, respecting the rule of step economy. While the domino approach involving alkenes and allenes is well investigated, examples involving alkynes are somewhat limited in the literature
Ejjoummany, Abdelaziz. "Design et fonctionnalisation d’hétérocycles originaux de type bicycliques [5-5] et tricycliques [6-5-6] à visée thérapeutique potentielle." Thesis, Orléans, 2020. http://www.theses.fr/2020ORLE3141.
Повний текст джерелаThe access to new original biologically active heterocyclic compounds, is one of the main objectives of our research group. In this context, the main purpose of this thesis is the design of three new families of heterocyclic compounds containing a pyrazolic motif that may exhibit biological activities, namely pyrido[1',2': 1.5]pyrazolo[4,3-d]pyrimidine, pyrrolo[3,4-c]pyrazole and pyrazolo[5,1-b]thiazole.This manuscript is essentially dedicated to a methodology work describing the different routes of access to these originals and potentially modular tricyclic and bicyclic precursors. The reactivity of these key synthons is then studied towards aromatic nucleophilic substitutions reactions and various pallado-catalyzed methods of functionalization (Activation with PyBrOP- (hetero) arylation, Liebeskind-Srogl, Suzuki-Miyaura, Buchwald-Hartwig, C-H arylation, aromatic nucleophilic substitution) to develop interesting libraries built around these unusual structures, thus opening numerous pharmacological perspectives
Li, Bin. "Ruthenium(II) catalyzed C-H bond functionalization and hydrosilylation reactions." Thesis, Rennes 1, 2013. http://www.theses.fr/2013REN1S114.
Повний текст джерелаIn this research doctoral thesis, we have shown that imines, 2-phenylpyridine, 2-phenyloxazoline, phenylpyrazole, benzo[h]quinoline led to cyclometallated ruthenium(II) complexes from [RuCl2(p-cymene)]2 and KOAc via sp2 C-H bond activation. [RuCl2(p-cymene)]2 /KOAc/PPh3 is an efficient catalytic system for diarylation of imines and 2-phenyloxazolines in water, which gave higher activity than in organic solvents. Bulky amines were then synthesized through sequential catalytic C-H arylation and hydrosilylation of imines using [RuCl2(p-cymene)]2 catalyst. Challenging selective mono arylation of 2-pyridyl arylketones, leading to six-membered ruthenacycle intermediate, difficult to perform, was achieved with in situ generated Ru(O2CC6H4CF3)2(p-cymene) catalyst. The direct dehydrogenative oxidative alkenylation of aryloxazolines with styrenes and acrylates was catalyzed by [RuCl2(p-cymene)]2/BNPAH (1,1′-binaphthyl-2,2′- diylhydrogenophosphate) catalytic system in the presence of Cu(OAc)2.H2O as an oxidant in air. Tandem catalytic oxidation of 2-pyridylmethanols and selective sp3 C-H (mono or di) α-alkylation of 2-pyridyl ketones with functional alkenes was performed by using [RuCl2(p-cymene)]2 complex in the presence of Cu(OAc)2.H2O in DCE or toluene. In the second part, it is shown that, [RuCl2(p-cymene)]2 is a very efficient catalyst for the hydrosilylation of imines and primary amides. A wide range of aldimines and ketimines were successfully reduced to corresponding amines in high chemoselectivity by using PMHS as greener silane in ethanol at RT. Moreover, challengingly, primary amides could be selectively converted by hydrosilylation to the secondary amines under solvent free conditions
Meng, Di. "Caffeine-derived-iron catalyzed carbonyl-ene and Diels-Alder reactions and development of an NHC-diol ligand family." Doctoral thesis, Université Laval, 2018. http://hdl.handle.net/20.500.11794/30271.
Повний текст джерелаIron has many advantages compared to other transition metals in homogeneous catalysis, such as relatively cheap price, eco-friendly, good catalytic activities. Hence, these features boosted the development of iron catalysis since 15 years ago. In this thesis, various iron salts including FeII and FeIII were examined as Lewis acid catalysts in the intermolecular carbonyl-ene reaction of various alkenes and ethyl 3,3,3-trifluoropyruvate. FeII salts, such as FeCl2, Fe(OAc)2, Fe(NTf)2, Fe(ClO4)·6H2O, Fe(BF4)2·6H2O, Fe(OTf)2, were found to be effective in catalyzing the reaction. An anhydrous Fe(BF4)2 catalytic system was developed for both of an intermolecular carbonyl-ene reaction of various alkenes and ethyl 3,3,3-trifluoropyruvate and an intramolecular carbonyl-ene reaction of (S)-citronellal. The ene-products, i.e. homoallylic alcohols, were afforded in 36-87% yields giving a scope of various with 1,1-disubstituted alkenes and the cyclization of citronellal. N-heterocyclic carbenes (NHC) are recognized as promising ligands in transition metals catalysis. Three caffeine-derived xanthinium salts were used as NHC precursors to transition metals iron for developing an NHC-iron catalyst in the intermolecular carbonyl-ene reaction and the intramolecular carbonyl-ene reaction of citronellal. Optimized conditions were developed from the screening of iron salts, solvents, catalyst loading and counter anions. Fe(OTf)2 was found to efficiently catalyze the reaction while complexed with NHC ligand derived from methylated caffeine xanthinium salt. Caffeine-derived-[NHC-Fe]2+(SbF6)22− catalyzed carbonyl-ene reaction of various enophiles with ethyl trifluoropyruvate afforded 22-99% yields in homoallylic alcohols. NHC-FeCl2[SbF6] was efficiently and selectively used as a catalyst to convert citronellal into the desired isopulegol. Caffeine-derived xanthinium salt was designed with Fe(OTf)2 as a recyclable catalyst for Diels-Alder reaction in dimethyl carbonate used as a green solvent. Several other green solvents were examined to further study the application of green solvents in organic synthesis. The catalyst, derived from a caffeine-derived xanthinium salt and Fe(OTf)2, was recycled up to five times, while maintaining the same level of yields for the Diels-Alder reaction and recyclability. A relative large scope of substrates including bidentate dicarbonyl compounds, ketones, aldehydes, and esters were tested. Alkoxyl-NHC ligands were developed as a rising family of ligands in enantioselective conjugate addition. A series of new NHC-diol ligands were designed and tested in the carbonyl-ene reaction. These newly developed ligands are promising systems in asymmetric catalysis and transition metal catalysis.
Hedouin, Jonathan. "Etude de cascades réactionnelles pallado-catalysées de fermeture d’allènamides et d’allylation directe de liaisons C-H et C-CO2H d’azoles, d’énamides et d’acides propioliques pour la diversité structurelle." Thesis, Normandie, 2017. http://www.theses.fr/2017NORMIR21/document.
Повний текст джерелаThe design of efficient and eco-friendly atom and step-economical synthetic plans of molecules using highly available starting materials is one of major objectives of organic chemist. Transition metal catalysis has allowed a bold step to build and functionalize consecutively, through a one-pot reaction, major nitrogen-containing heterocycles which are broadly present into numerous natural products, pharmaceutics and agrochemicals. The catalysis is based upon tandem inner-sphere elemental chemical transformations and one of major current challenge is to implement catalytic metallation of C-CO2H and C-H bonds. Involved in this young field of research initiated since the past decade from sevaral groups including pioneering and high active Jieping Zhu team of the Polytechnic School of Lausanne, the present study has been directed towards the design of innovative palladium-catalyzed domino Grigg nitrogen-containing heterocycles building through ortho-halogeno allenamides intramolecular carbopalladation process followed by direct C-H allylation of heterocycles and enamides or direct decarboxylative allylation of propiolic acids. After demonstrating the reactivity of nitrogen-conjugated pi-allypalladium complex in direct C-H allylation of acidic heterocycles, first palladium-catalyzed tandem build and heteroarylation of 1(2H)-isoquinoleinone and indole from ortho-halogeno allenamides was first envisaged. Efforts were next directed to the setting up of a one-pot protocol including in situ generation of allenamide followed by palladium-catalyzed domino building and functionalization of heterocycles. It was then hugely evaluated to the preparation of indole, 1(2H)-isoquinoleinones, isoquinolins as well as high-membred ring heterocycles such as benzo-(2H)-azepine and benzo-(2H)-azocine embedding with oxadiazoles and oxa(thia)zoles. An first extended synthetic concept towards the palladium-catalyzed tandem build and propargylation of nitrogen-containing heterocycles using sevral propiolic acids as coupling partners
Belaroussi, Rabia. "Synthèse et fonctionnalisation de nouveaux dérivés tricycliques [6-5-6] polyhétéroaromatiques à visée thérapeutique potentielle." Thesis, Orléans, 2016. http://www.theses.fr/2016ORLE2002/document.
Повний текст джерелаThe discovery of new candidates to fight against various diseases, namely cancer and neurodegenerative diseases, is one of the main goals of our research group. In this context, the main purpose of this thesis, is the design of two new classes of heterocyclic planar structure, to date, rarely studied, namely pyrido[2’,1’ :1,5]pyrazolo[3,4-d]pyridazines and pyrido[2’,1’ :1,5]pyrazolo[3,4-d]pyrimidines. This manuscript is essentially dedicated to a methodology work describing the different routes of access to these originals and potentially modular tricyclic precursors. The reactivity of these key synthons is then studied towards aromatic nucleophilic substitutions reactions and various palladocatalyzed methods of functionalization (Suzuki-Miyaura, Buchwald-Hartwig, activation PyBrOP-(hetero) arylation) to develop interesting libraries built around these unusual structures, thus opening numerous pharmacologicals perspectives
Ye, Fei. "Ru- and Rh-catalyzed [2+2+2] cycloadditions : an access to fluorenone, 2-aminopyridine, and 1,3-dihydroisobenzofuran derivatives." Thesis, Paris 6, 2017. http://www.theses.fr/2017PA066347/document.
Повний текст джерелаThis manuscript focused on the development of eco-friendly and mild processes to access original carbocyclic and heterocyclic scaffolds of biological interest through transition-metal-catalyzed [2+2+2] cycloaddition reactions. Initially, an efficient and practical route for the preparation of highly substituted fluorenones and analogues via solventless RuCl3·nH2O-mediated [2+2+2] cycloaddition of benzoyl bridged [alpha, omega]-diynes and alkynes was developed. Secondly, various functionalized 2-aminopyridine derivatives were synthesized using both neutral RuCl3·nH2O and cationic Cp*Ru(CH3CN)3PF6 complexes to catalyze the [2+2+2] cycloaddition of diynes and cyanamides under solvent-free conditions. With Cp*Ru(CH3CN)3PF6 as catalyst, excellent regioselectivities were achieved to provide a wide range of 2-aminopyridines of high synthetic utility involving halopyridines, vinyl pyridines and amino-aza-fluorenones. Finally, the enantioselective rhodium-catalyzed [2+2+2] cycloaddition of prochiral triynes and monoalkynes was carried out in the presence of cationic [Rh(cod)2]BF4/(R)-BINAP complex to provide enantioenriched 1,3-dihydroisobenzofuran derivatives containing a quaternary carbon stereogenic center
Yuan, Kedong. "Palladium-catalyzed sp² C-H bond functionalization : construction of photoswitches and desulfitative cross-couplings." Thesis, Rennes 1, 2015. http://www.theses.fr/2015REN1S136/document.
Повний текст джерелаDuring this thesis, we were interested in the synthesis of organic photo-switches [DAE, di(hetero)arylethenes] via palladium catalyzed sp2 C-H bond activation of heteroaromatics. The previously established catalysts system for direct arylation, Pd(OAc)₂/KOAc/DMA, was found to be suitable for the new desired transformations. This method allows the straightforward access to a wide variety of useful photo-switchable molecules in a few steps. Moreover, during the course of further developments of C-H bond functionalization of heteroaromatics, we found that a phosphine free catalytic system, Pd(CH₃CN)₂Cl2/Li ₂CO₃/dioxane, promotes the coupling of thiophenes and arylsulfonyl chlorides to afford unexpected β-arylated products. This new catalytic system can also be utilized in conjugate addition reaction by using enones and arylsulfonyl chlorides as coupling partners. Finally, we describe PdCl2/CuBr co-catalyzed formation of 4-aryl-1,2,3,4-tetrahydroquinolines via cascade desulfitative Heck/sp² C-H activation sequence
Souffrin, Agathe. "Conception, synthèse et évaluation pharmacologique de maléimides, inhibiteurs potentiels de l'intégrase du VIH-1." Thesis, Tours, 2012. http://www.theses.fr/2012TOUR3801/document.
Повний текст джерелаOur research team has recently developed the first inhibitors of a DDE enzyme, MOS1 transposase, an enzyme similar to the HIV-1 integrase. These molecules, having a bisfurylmaleimide structure, also showed efficacy against enzymatic activities of HIV integrase. Based on these results, we undertook the synthesis of new bisfurylmaleimides in order to identify new integrase inhibitors and propose new molecules in the fight against the virus that causes AIDS. The originality of our approach is the use of MOS1 transposase as a model for designing our molecules. Methodologies used to access these molecules are essentially involving chemistry catalyzed by transition metals but also reactions of heterocyclic chemistry such as Mitsunobu, Knoevenagel or Horner-Wadsworth-Emmons reactions. All synthesized molecules has been evaluated for their inhibitory activities on the MOS1 transposase and HIV-1 integrase. Their antiviral properties against HIV were also evaluated. Parallel to this work, we investigated the reactivity of the maleimide core in palladium-catalyzed cross-coupling reactions especially in Sonogashira couplings
Zhao, Liqin. "Palladium-catalyzed direct arylation via sp² and sp³ C-H activation of hetero(aromatics) and hydrocarbons for C-C bond formation." Thesis, Rennes 1, 2014. http://www.theses.fr/2014REN1S038/document.
Повний текст джерелаDuring this thesis, we were interested in the sp² and sp³ C-H bond activation catalyzed by palladium catalysts for the preparation of (hetero)aryl-aryls and biaryls. This method is considered as cost effective and environmentally attractive compared to the classical couplings such as Suzuki, Heck, or Negishi. First we described the palladium-catalyzed direct C2-arylation of benzothiophene in the absence of phosphine ligand with high selectivity. We also demonstrated that it is possible to active both C2 and C5 C-H bonds for access to 2,5-diarylated compounds in one step, and also to non-symmetrically substituted 2,5-diarylpyrroles via sequential C2 arylation followed by C5 arylation. We also studied the reactivity of polychlorobenzenes via palladium-catalyzed C-H activation. We finally examined the palladium-catalysed selective sp² and sp³ C-H bond activation of guaiazulene. The selectivity depends on the solvent and base: sp² C2-arylation (KOAc in ethylbenzene), sp² C3-arylation (KOAc in DMAc) and sp³ C4-Me arylation (CsOAc/K₂CO₃ in DMAc). Through this method, a challenging sp³ C-H bond was activated
Lin, Pei-shiuan, and 林佩萱. "CO oxidation catalyzed by Au nanoclusters." Thesis, 2008. http://ndltd.ncl.edu.tw/handle/20387342561430558009.
Повний текст джерела國立中正大學
物理所
96
Gold nanoclusters supported on suitable oxide layers are active for carbon monoxide oxidation, which were discovered in 1987. Instead of employing oxide support, we have studied the catalytic activity of gold nanoparticles on highly oriented pyrolytic graphite (HOPG). HOPG surface is non-polar, inert, and easy to prepare. Gold atoms are deposited onto HOPG via molecular beam epitaxy. Atomic force microscopy is used to observe the morphology and the size of gold clusters on HOPG. After gold deposition, the HOPG substrate is heated to a range of temperatures to obtain Au nanoclusters of desired sizes. Oxygen gas and carbon monoxide gas are then leaked into the chamber. Residual gas analyzer is used to measure the partial pressures of carbon monoxide, oxygen, and carbon dioxide. For gold clusters larger than 10 nm, which are prepared by heating the HOPG substrate to above 320K, we find there is no catalytic activity for gold clusters on the oxidation of carbon monoxide. For gold clusters with an average size less than 5 nm, prepared by heating the substrate to 303K, we detect an increase in the partial pressure of carbon dioxide, a clear indication of catalytic effect by gold clusters. We have also observed the increase in carbon dioxide partial pressure as the density of the gold clusters increase.
Jian, Ke-Ren, and 簡克任. "Growth and fabrication of Au-catalyzed GaAs nanowire solar cells on Si substrates." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/12697817149602857973.
Повний текст джерела國立清華大學
材料科學工程學系
100
In comparison with silicon solar cells, the GaAs cells offer the advantage of having high absorption coefficient and direct bandgap. In particular, the GaAs cells in the form of coaxial nanowires offer the further advantage of having optimal light absorption and enhanced carrier collection, and thus have great potential to implement advanced high efficiency schemes. Synthesis and fabrication of GaAs nanowire solar cells on GaAs substrates has been widely investigated. However, epitaxial growth of GaAs nanowires on Si substrates has been rarely reported. In this work, we report the realization of GaAs nanowire solar cells on Si substrates. Synthesis of p-n coaxial GaAs nanowires was achieved by means of the Au-catalyzed vapour-liquid-solid (VLS) method by MBE using Be and Si as the p-type and n-type dopants, respectively. In device process, photoresist was first spin coated on the nanowire sample, followed by oxygen plasma etch to remove the photoresist from the tip of the nanowires. Indium tin oxide was then deposited on top of the nanowires by e-beam evaporation and annealed for 10 min to form transparent contact to the sample surface. Morphology of the devices was analyzed by scanning electron microscopy and I-V characteristics were measured using a solar simulation system. The results reveal a good progress for the use of GaAs nanowires in the fabrication of third generation solar cells on Si substrates.
Hsu, Chia-Ling, and 許嘉玲. "Au(I)-Catalyzed Cyclization of Methyl 2-(2-Alkynylphenylethynyl) Benzoates to 6H-Dibenzo[c,h]chromen-6-ones and Synthesis of Arnottin I." Thesis, 2012. http://ndltd.ncl.edu.tw/handle/92891328567668102702.
Повний текст джерела國立中山大學
化學系研究所
100
Gold catalysts have the characteristic of promoting nucleophilic reaction. The cyclization reaction of enediynes catalyzed by gold activated by silver in toluene at 100oC to give 6H-dibenzo[c,h]chromen-6-ones (63), 6H-benzo[c]chromen-6-one (66) and Arnottin I (10) is described. Treatment of enediynes (61、65) with 5 mol% of Ph3PAuCl and 10 mol% of AgSbF6 in toluene at 100oC gave 6H-dibenzo[c,h]chromen-6-ones (63) and 6H-benzo[c]chromen-6-one (66) in good yield. In addition to using gold catalyst, electrophilic reagents employed in the reaction caused one cyclization instead of two cyclization. Furthemore, a mechanistic study and GC-MS data showed that the toluene could participate in the reaction. Enediynes (73) can be synthesized by a series of organic synthesis with few steps. Treatment of enediynes (73) with 5 mol% of Ph3PAuCl and 10 mol% of AgSbF6 in toluene at 100oC gave natural product-Arnottin I (10).
Cho, Eun Jin. "I. Pt, Au, and Ru-catalyzed Reactions of multi-ynes: reactivity and selectivity : II. Synthetic studies on natural products: (3R,9R,10R)-panaxytriol and (-)-dactylolide /." 2008. http://www.library.wisc.edu/databases/connect/dissertations.html.
Повний текст джерелаPoupart, Julien. "Synthesis, diversification and biomedical applications of 4,5-substitued N-aminoimidazol-2-ones." Thesis, 2020. http://hdl.handle.net/1866/24770.
Повний текст джерелаLe développement de mimes de tours peptidiques pose un intérêt particulier en chimie médicinale, en raison de leur importance dans la reconnaissance moléculaire. Dans ce contexte, les résidus N-aminoimidazol-2-one (Nai) ont démontré une tendance à occuper la position centrale de repliements peptidiques. De plus, la présence de l’unité imidazolone offre un potentiel de fonctionnalisation en position 4 et 5 pouvant jouer le rôle de chaînes latérales rigidifiées dans l’espace χ. Des méthodes ont été développées pour rendre possible l’utilisation de résidus Nai en chimie peptidique. Par le passé, des esters de dipeptide Nai possédant un substituant à la position 4 de l’hétérocycle ont été synthétisés de manière racémique. L’utilisation de groupement C-terminaux a permis de grandement réduire l’épimérisation due à l’utilisation de base forte utilisée durant l’étape de cyclisation. La fonctionnalisation de la position 5 du cycle après la cyclisation a aussi été rendue possible par le développement de nouvelles conditions réactionnelles. Par exemple, des conditions de formylation ont donné des résidus (4-Me, 5-Aldéhyde)Nai. La fonction aldéhyde a été réduite et oxydée, donnant accès a des fonctions alcool et acide carboxylique. L’amination réductrice du squelette (4-Me, 5-Aldéhyde)Nai en utilisant des amines primaires et secondaires ainsi que l’amino-méthylation de résidus (4-Me)Nai ont donné accès à des résidus d’acide diaminobutyrique rigidifiés. Dans le but de préparer des analogues Nai pouvant servir de mimes rigidifiés de résidus phénylalanine, la catalyse au palladium a rendu possible l’installation de groupements 5-aryle par couplage croisé avec différents iodoaryles. Dans un modèle de peptide, le résidu (4-Me, 5-aryl)Nai a été soumis à une analyse par dynamique moléculaire qui a révélé le positionnement de la portion Nai à la position i+1 d’un tour β de type II’, avec la chaine latérale aryle adoptant une conformation gauche (-). Ayant en main des conditions de synthèse énantioenrichie ainsi que de diversification de la position 5, la construction de peptides Nai possédant un intérêt biologique a été entreprise. Des dérivés du peptide Growth hormone releasing peptide-6 (GHRP-6) ont été ciblés car les analogues semicarbazide correspondant ont précédemment démontré avoir à la fois de la sélectivité et une affinité relativement grande pour le Cluster of differentiation receptor (CD36). Ils ont ainsi le potentiel de moduler l’inflammation attribuable aux macrophages dans des conditions menant à la dégénérescence maculaire liée à l’âge, l’athérosclérose et l’angiogenèse. Des études précédentes ont démontré que le remplacement du résidu Trp4 du GHRP-6 par un semicarbazide possédant une chaîne latérale aromatique favorisait l’adoption d’un repliement de la chaîne peptidique et une affinité sélective envers le récepteur CD36. Une méthode de synthèse sur phase solide d’analogues [(4-Me, 5-Aryle)Nai4]-GHRP-6 a été développée et utilisée pour synthétiser quatre différents peptides Nai en utilisant la résine Rink amide. Les quatre analogues se sont montrés efficaces à réduire la surproduction d’oxide nitrique (NO) dans les cellules macrophages traitées avec un agoniste du Toll-like receptor 2 (TLR2). Malgré le fait que l’évaluation biologique des analogues [(4-Me, 5-Aryle)Nai4]-GHRP-6 soit toujours en cours, leur habilité à moduler la surproduction d’oxide nitrique montre qu’ils possèdent la bonne géométrie quant à la chaîne principale et la chaîne latérale aromatique pour interagir avec le récepteur. En somme, la présente thèse a fourni des méthodes efficaces de synthèse de nouveaux analogues de peptides rigidifiés pour mimer les chaînes principale et latérales de tours β. Les résidus Nai énantioenrichis ont été synthétisés, introduits dans des séquences peptidiques d’intérêt sur phase solide et fonctionnalisés à la 4ième et 5ième position. L’utilisation de ces analogues Nai 4,5-disubstitués en chimie médicinale et peptidique offre un potentiel considérable dans l’exploration de la relation structure-activité de peptides d’intérêt biologique pour identifier et mimer les conformères bioactifs.
Genest, Nicolas. "Synthèse et analyse conformationelle de dipeptides contenant l’isostère hydroxyéthylène." Thèse, 2010. http://hdl.handle.net/1866/4664.
Повний текст джерелаIn this thesis, I discuss my studies toward the synthesis of substituted homoallylic ketones from the copper-catalyzed cascade addition of substitued vinyl Grignard reagents to carboxylic esters. The homoallylic ketones were used to provide different peptidomimetics containing a hydroxyethylene isostere instead of an amide bond. The methyl ester of phenylalanine and serine derivatives were reacted in copper-catalyzed cascade additions of substitued vinylmagnesium bromide to provide substitued homoallylic ketone intermediates. Selective reduction of the ketone to an alcohol, oxidative cleavage of the double bond, followed by peptide coupling with amino acid lead to the desired peptidomimic. The influence of changing the central amide bond for a hydroxyethylene isostere in a β-turn and the effect of a gem dimethyl group on the backbone conformation adopted by the newly synthesized tripeptides, were studied by X-ray diffraction and solution NMR spectroscopy using NOESY experiments. From these studies, it was revealed that the iso-butyric acid hydroxyethylene isomer induced a β-turn-like conformation, and may serve as a novel scaffold for peptide mimicry.