Relevant bibliographies by topics / Alkyne group / Dissertations / Theses
To see the other types of publications on this topic, follow the link: Alkyne group.

Dissertations / Theses on the topic 'Alkyne group'

Author: Grafiati
Published: 24 April 2022

Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles

Select a source type:

Consult the top 50 dissertations / theses for your research on the topic 'Alkyne group.'

Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.

You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.

Browse dissertations / theses on a wide variety of disciplines and organise your bibliography correctly.

1

Harding, David James. "Redox-active group 6 transition metal alkyne complexes." Thesis, University of Bristol, 2000. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.324328.

Full text
APA, Harvard, Vancouver, ISO, and other styles
2

Boonyuen, Supakorn. "The redox chemistry of Group 6 metal alkyne complexes." Thesis, University of Bristol, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.420906.

Full text
APA, Harvard, Vancouver, ISO, and other styles
3

Humphrey, James Stuart. "Group 15 and alkyne derivatives of HR₄CO₁₂BH₂." Thesis, University of Cambridge, 1995. https://www.repository.cam.ac.uk/handle/1810/273012.

Full text
APA, Harvard, Vancouver, ISO, and other styles
4

Elser, Iris [Verfasser], and Michael R. [Akademischer Betreuer] Buchmeiser. "(Pre-)ionic and/or chiral alkene and alkyne metathesis catalysts of group 6 / Iris Elser ; Betreuer: Michael R. Buchmeiser." Stuttgart : Universitätsbibliothek der Universität Stuttgart, 2018. http://d-nb.info/1183678274/34.

Full text
APA, Harvard, Vancouver, ISO, and other styles
5

Bartlett, Ian Mark. "The redox activiation of alkyne ligands in group 6 transition metal complexes." Thesis, University of Bristol, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.390376.

Full text
APA, Harvard, Vancouver, ISO, and other styles
6

Fauché, Kévin. "NHC portant des azotures : intermédiaires dans la synthèse catalysée d‘hétérocycles polyazotés et auto-fonctionnalisation de complexes métal-NHC." Thesis, Université Clermont Auvergne‎ (2017-2020), 2018. http://www.theses.fr/2018CLFAC062/document.

Full text
Abstract:
Les carbènes N-hétérocycliques (NHC) sont très utilisés pour complexer les métaux de transition. Ils quittent rarement ce rôle de ligand ancillaire et trouvent, depuis une vingtaine d’années, des applications en catalyse ou, plus récemment, en chimie médicinale. Dans ce travail, nous discuterons d’une méthode de synthèse douce conduisant à la formation de complexes AgI – NHC via une source d’argent soluble. Cette méthode nous a permis d’obtenir des complexes bien connus mais également d’accéder à une nouvelle série de complexes NHC-Ag-phosphine. Nous présenterons également une nouvelle réaction où des NHC portant une fonction azoture à proximité du carbone du carbène quittent leur rôle de ligand ancillaire et conduisent à la formation d’hétérocycles azotés par cyclisation carbène-nitrène. Cette réaction sera présentée en détail, ainsi que la caractérisation spectroscopique concernant une sous-série de composés fluorescents obtenus par cette méthode. Enfin, nous présenterons une stratégie de post-fonctionnalisation de complexes développée dans notre équipe. Des complexes argent(I)-NHC portant un azoture proches du centre carbénique catalysent leur propre fonctionnalisation. De plus, des complexes de cuivre(I) portant des azotures en position éloignée du centre métallique seront greffés sur des nanoparticules magnétiques pour servir de catalyseur recyclables
N-heterocyclic carbenes (NHC) are widely used to complex transition metals. They rarely leave their role as ancillary ligand and find, since 20 years, applications in catalysis or, more recently, in medicinal chemistry. In this work, we will discuss a mild synthetic method leading to the formation of AgI – NHC complexes via a soluble silver species. This method allowed us to obtain well known complexes but also to access a new series of NHC-Ag-phosphine complexes. We will also present a new reaction where NHC ligands bearing an azide function close to the carbenic center leave their role as ancillary ligand and lead to the formation of nitrogen rich heterocycles by a carbene-nitrene cyclization. This reaction will be presented in detail, along with the spectroscopic characterization regarding a sub-series of fluorescent compounds obtained by this method. Finally, we will present a post-functionalization strategy of complexes developed in our team. Silver(I)-NHC complexes tagged by an azide close to the carbenic center catalysed their own functionalization. Moreover, copper(I) complexes tagged by an azide function in a distant position from the metallic centre will be grafted on magnetic nanoparticles to act as recyclable catalysts
APA, Harvard, Vancouver, ISO, and other styles
7

Yahya, Rosiyah. "Alkane hydrogenolysis on supported Group VIII metals." Thesis, Brunel University, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.257670.

Full text
APA, Harvard, Vancouver, ISO, and other styles
8

Coles, Stuart Raymond. "Half-sandwich group 4 complexes in alkene polymerisation." Thesis, University of Warwick, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.439647.

Full text
APA, Harvard, Vancouver, ISO, and other styles
9

Bismuto, Alessandro. "Main group species for catalytic hydroboration." Thesis, University of Edinburgh, 2018. http://hdl.handle.net/1842/31537.

Full text
Abstract:
Modern synthetic chemistry is unimaginable without transition metal catalysis. Yet the often high cost, toxicity and scarcity of many transition metals is driving attempts to find sustainable alternatives. Thus, the development of catalytic processes using main-group catalysts is now of broad interest. This thesis reports the development of a facile protocol for the aluminium-catalysed hydroboration of alkynes, alkenes and polar bonds using commercially-available catalysts. The catalytic hydroboration is proposed to occur by hydroalumination followed by product release through σ-bond metathesis with pinacol borane. An alternative route to alkenyl boranes is the 1,1-carboboration of alkynes using stoichiometric B(C6F5)3. A zwitterionic intermediate in the Piers' borane-catalysed hydroboration and 1,1-carboboration of alkynes with B(C6F5)3 has been characterised and its divergent reactivity identified. This has led to the development of a B(C6F5)3 - catalysed hydroboration of alkynes using HBpin.
APA, Harvard, Vancouver, ISO, and other styles
10

Gustafson, Samantha Jane. "Computational Studies of Alkane C-H Functionalization by Main-Group Metals." BYU ScholarsArchive, 2016. https://scholarsarchive.byu.edu/etd/5992.

Full text
Abstract:
The most efficient homogeneous catalysts for hydroxylation of light alkanes utilize transition metals in superacid solvent and operate by tandem electrophilic C-H activation/metal-alkyl (M-R) functionalization. An emerging alternative strategy to transition metals is the use of high-oxidation state main-group metals (e.g. TlIII, PbIV, IIII) that hydroxylate light alkanes. This dissertation reports density-functional theory calculations that reveal the mechanisms, reactivity, and selectivity of TlIII promoted alkane C-H functionalization in trifluoroacetic acid and TlIII-dialkyl functionalization in water. Calculations reveal that TlIII oxidizes alkanes via a closed-shell C-H activation and M-R functionalization mechanism that is similar to transition-metal C-H functionalization mechanisms. Comparison of TlIII to similar transition metals reveals that while TlIII and transition metals can have similar activation barriers for C-H activation, TlIII M-R functionalization is significantly faster due to a highly polar Tl-C bond and large TlIII/TlI reduction potential. The combination of a moderate C-H activation barrier combined with a low M-R functionalization barrier is critical to the success for TlIII promoted alkane C-H oxidation. The proposed TlIII C-H activation/M-R functionalization mechanism also provides an explanation for ethane conversion to a mixture of ethyl trifluoroacetate and ethane-1,2-diyl bis(2,2,2-trifluoroacetate). The reactivity of TlIII contrasts the lack of alkane oxidation by HgII. The C-H activation transition state and frontier-orbital interactions provide a straightforward explanation for the higher reactivity of TlIII versus HgII. This frontier-orbital model also provides a rationale for why the electron-withdrawing group in EtTFA provides "protection" against overoxidation. Calculations also reveal that TlIII-dialkyl functionalization by inorganic TlIII in water occurs by alkyl group transfer to form a TlIII-monoalkyl complex that is rapidly functionalized.
APA, Harvard, Vancouver, ISO, and other styles
11

Durkin, Julie Joanne. "Phosphametallocenes of group 14 and other novel compounds derived from phospha-alkynes." Thesis, University of Sussex, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.307725.

Full text
APA, Harvard, Vancouver, ISO, and other styles
12

Chavez, Vasquez Patricia. "Intramolecular diamination of alkenes : Palladium- and main group catalysis." Strasbourg, 2011. http://www.theses.fr/2011STRA6054.

Full text
Abstract:
Au cours de ce travail de thèse, des réactions catalytiques de diamination d’alcènes terminaux et fonctionnalisés ont été développées. La première partie de la thèse traite de la transformation d’alcènes fonctionnalisés en dérivés 2,3-diaminés. La diamination intramoléculaire d’acrylates urées 2 se fait en utilisant des sels de palladium (II), en tant que catalyseur, CuBr2 comme oxydant, ainsi que Na2PO4 ou Cs2CO3 comme base. Différentes sources d’azote ont été testées pour mettre en évidence la généralité de cette réaction ainsi que pour observer la différence de réactivité et de stéréosélectivité en découlant. De manière générale, cette réaction de diamination permet d’obtenir de très bons rendements et ne demande pas de conditions de réalisation strictes. Cette réaction de diamination oxydante dépend de la polarité du solvant utilisé mais pas de la source de palladium (II) utilisée. La réaction est entièrement diastéréosélectivité et se déroule à priori par un mécanisme durant lequel le palladium passe par un haut degré d’oxydation intermédiaire. Les composés acrylates-urées ont été les premiers testés et ont montré que les produits de diamination sont formés avec une excellente stéréosélectivité et complète chimiosélectivité. Des études préliminaires du mécanisme de cette réaction ont montré que le cycle catalytique débute par une syn-aminopalladation 3 suivie d’une amination directe, sans précédent, de la liaison C-Pd en position alpha du groupe ester 6, donnant le produit syn majoritairement 7. (Schéma 1) Ceci ayant été vérifié par diffraction des rayons X. Bien que ces produits aient été utilisés lors d’une synthèse d’un produit naturel, (+/-)-absouline, l’inconvénient majeur d’une telle méthode réside dans la déprotection des imidazolidinones, issues du cycle catalytique, en diaminoesters libres. Schéma 1. Cycle catalytique de la diamination des urées avec des alcènes fonctionnalisés catalysée par le palladium. C’est la raison pour laquelle, la réaction de diamination des acrylates-sulfamides 9 portant des groupes différents a été envisagée. Lors de précédentes études de diamination catalytique d’alcènes terminaux en présence de sulfamide, un catalyseur à base de nickel a été utilisé, donnant de bons rendements de diamination. Ce système catalytique n’a cependant montré aucune réactivité envers d’autres alcènes fonctionnalisés (acrylates). Les conditions précédentes (palladium (II) et CuBr2) ont donc été testées et ont donné diastéréosélectivement et chimioselectivement les composés de diamination avec des rendements de 80-95%. Les études mécanistiques de la réaction de diamination des alcènes en présence de sulfamides ont montrées que la première étape était également une syn-aminopalladation 10, mais cette fois-ci suivie de la formation d’un intermédiaire bromo-aminé 12. (Schéma 2) Pour finir, en présence d’une base, un déplacement de type SN2 prend place, et mène à majoritairement au produit de configuration anti 13, configuration opposée à celle obtenue dans le cas des composés acrylates-urées 7. Schéma 2. Cycle catalytique de la diamination des sulfamides avec des alcènes fonctionnalisés catalysée par du palladium. L’intermédiaire bromo-aminé 12 de cette réaction a été isolé et caractérisé dans un cas, les différentes configurations des produits diaminés obtenus (anti et syn), ont été tout d’abord déterminées par RMN (constante de couplage†: produit syn J =8-10 Hz; produit anti J = 4-6 Hz) et finalement vérifiées par diffraction des rayons X. Par la suite, des améliorations de cette réaction de diamination ont été envisagées et le premier objectif consistait à changer le type de catalyseur. La présence d’intermédiaires aminohalogénés dans le système Pd/CuBr2 de diamination a amené à développer une nouvelle réaction catalytique de diamination intramoléculaire. Dans un premier temps, il a été observé que les substrats utilisés dans la catalyse au palladium, avec des alcènes terminaux ou fonctionnalisé, subissent une diamination en l’absence de palladium, lorsqu’ils sont traités avec une quantité steochiométrique de IPy2BF4. Des expériences par RMN in situ montrent un intermédiaire de type amino-iode formant ensuite la diamine par une réaction finale de type SN2. Finalement, au cours des derniers travaux de diamination des oléfines en présence d’halogènes, il a été observé que les ions de type X+ (X=I, Br) initiant la réaction peuvent être régénérés en présence d’un oxydant. Diverses sources de bromure ont été testées avec différentes quantités d’oxydant. La réaction catalytique avec le meilleur taux de conversion a été observée dans les conditions suivantes: 5% de CaBr2. XH2O, 1. 5 équivalents de PhI(OAc)2 et 1. 5 équivalents de NaOAc. Toujours dans la même optique, différents oxydants ont été testés. Cette optimisation a permis de trouver de meilleurs conditions pour cette réaction de diamination catalytique des alcèes sans métal de transition : 10% KBr, 3. 0 équivalents de NaClO2 (oxydant), 2. 5 équivalents de NaOAc (base) dans le DMF à 30-40 C pendant 5-12 heures (Schéma 3). Schéma 3. Diamination d’oléfines par la présence catalytique d’halogène. Cette réaction de diamination catalysée par le sel de bromure est beaucoup plus générale et chimiosélective, en comparaison aux réactions catalysées par le palladium ou le nickel. La réaction tolère également les urées comme les sulfamides et les produits obtenus à partir de ces sources azotées avec des alcènes simples ou fonctionnalisés ont été isolés avec de très bons rendements. Cette procédure a également permis d’effectuer la diamination d’alcènes internes, ainsi que la formation de cycles à 6 (Schéma 3, n = 2)
The results obtained during this thesis are fundamental in the area of nitrogen transfer chemistry catalysed by metals. Three complementary protocols to provide a broad scope of different diamine products, which should serve a leading structures in pharmaceuticals, ligands or organocatalyst cores[283] were presented. Within this context, the first transition metal catalysed diamination of functionalised olefins is presented. A protocol to carry out this intramolecular reaction under mild conditions has been developed. It makes use of catalytic amounts of palladium(II) under oxidative conditions at 40 _C and uses ureas as the only nitrogen source:The reaction proceeds via a Pd(II)/(IV) cycle. The first step is a syn-aminopalladation followed by the formation of an a-palladated ester intermediate. The dissociation of the amide from the palladium followed by a C-C bond rotation leads to the intermediate Pd-allylic complex. Next, the oxidation of Pd(II) to Pd(IV) by copper bromide induces a SN2-type C-N bond formation to give the diamine product with syn-configuration. This methodology proceeds with complete chemoselectivity and good diastereoselectivity. The relevance of this new diamination methodology was successfully demonstrated. As a synthetic application of this new transformation, the formal total synthesis of (±)-absouline was carried out using an urea-alkene as starting material with good yield. Another important achievement of the present Thesis has been a significant advance of the methodology for the synthesis of cyclic sulfamides with good yields and selectivity:In this case, the transformation resulted in the opposite diastereoselectivity that was previously observed for the ureas. The configuration of the final products was determined as anti by the coupling constant (3J= 3. 6 Hz for sulfamides versus 3J=10. 0 Hz for ureas) and confirmed by the X-ray structure of the corresponding compounds. The mechanism was clarified by the isolation and characterization of an aminobrominated intermediate of the reaction. To show the pertinence of the products as eminent organic building blocks we exemplarily applied them in peptide chemistry. Finally, it was possible to develop a metal-free catalytic diamination reaction that employs KBr as the catalyst under oxidative conditions. At the beginning, PhI(OAc)2 was used as the oxidant but further screening of the reaction permitted its replacement by the inexpensive and nontoxic NaClO2. Equally, the reaction works with good to excellent yields to give 5- or 6-membered rings even with highly functionalised olefins or acrylates and also with different nitrogen sources such as ureas or sulfamides: With this, the development of the oxidative intramolecular diamination of alkenes has reached a mature state. Little conceptual novelty can be expected and future work should only be devoted to punctual cases that require additional special optimization
APA, Harvard, Vancouver, ISO, and other styles
13

Harding, Nigel Anthony. "β-thia-alkyl complexes of platinum group metals." Thesis, Imperial College London, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.283721.

Full text
APA, Harvard, Vancouver, ISO, and other styles
14

Adeosun, Adetenu Adebisi. "Novel alkylidenation, epimetallation and hydrometallation reactions of group 4 metal alkyls." Diss., Online access via UMI:, 2004. http://wwwlib.umi.com/dissertations/fullcit/3150494.

Full text
APA, Harvard, Vancouver, ISO, and other styles
15

Thorne, A. J. "Bivalent amides, alkyls, and aryloxides of the main group 4 elements." Thesis, University of Sussex, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.373918.

Full text
APA, Harvard, Vancouver, ISO, and other styles
16

Smith, S. J. "Novel alkyls, aryls and alkoxides of group 14 and 15 elements." Thesis, University of Sussex, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.373133.

Full text
APA, Harvard, Vancouver, ISO, and other styles
17

Stennett, Tom Edward. "Transformations of alkenes with group 6 metals : selective ethene oligomerisation and beyond." Thesis, University of Bristol, 2013. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.601327.

Full text
Abstract:
This thesis describes advances in the chemistry of alkenes with group 6 transition metals, with a focus on improving activation methods, ligands and mechanistic understanding for selective alkene trimerisation catalysis. Chapter 1 describes the current state of the field for this catalytic process, including the most important developments in ligand design, catalyst activation and substrate scope.
APA, Harvard, Vancouver, ISO, and other styles
18

Coward, Kathleen Margaret. "Studies into the adduct chemistry of group III and II metal alkyls." Thesis, University of Salford, 2001. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.395743.

Full text
APA, Harvard, Vancouver, ISO, and other styles
19

Gallagher, Timothy. "Directed Nickel-Catalyzed Allyl Methylation of Unactivated Alkenes Utilizing a Monodentate L-Type Directing Group." Scholarship @ Claremont, 2019. https://scholarship.claremont.edu/cmc_theses/2032.

Full text
Abstract:
Transition-metal-catalyzed cross-coupling reactions are reliable tools for forging C–C bonds. The Engle Lab has previously pioneered the intermolecular difunctionalization of unactivated alkenes facilitated by nickel catalysis, where regioselectivity is controlled through the use of a bidentate directing group. A limitation of existing methods is that allyl groups have not yet been successfully incorporated, as the electrophile scope has been limited to alkyl and aryl species. Fundamentally, C–C p-bonds have served as key building blocks for the assembly of complex molecules, and the ability to introduce allyl moieties in a controlled manner enables diverse, downstream functionalization in multi-step synthesis. This work focuses on the use of diverse azaheterocycle directing groups connected to non-conjugated alkenes. Through the use of nickel catalysis, we have been able to successfully introduce and preserve allyl and cinnamyl species at the g-position and alkyl zinc nucleophiles at the b-position with high yield under mild conditions. This novel, 1,2-allylalkylation can accommodate a vast array of substituents with different electronic and steric properties (>20 examples). Our efforts have shifted to exploring different monodentate directing groups and to conduct mechanistic studies to shed light on the catalytic cycle. Interestingly, electron-rich electrophiles provide nearly quantitative NMR and isolated yields, whereas electron-poor electrophiles lead to lower yields. We report a competition experiment to further elucidate this mechanism. While isolated yields were generally higher for electron-rich groups, a competition between p-OMe and p-CF3 electrophiles led to preferential incorporation of the trifluoromethyl-substituted coupling partner, which supports oxidative addition as the product-determining step.
APA, Harvard, Vancouver, ISO, and other styles
20

Rajam, Sridhar. "From high spin systems to photorelease: Reactivity of twisted-triplet alkene 1,2 biradical." University of Cincinnati / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1276526731.

Full text
APA, Harvard, Vancouver, ISO, and other styles
21

Pawlikowski, Andrew V. "Developments in late metal-mediated C-N bond forming reactions /." Thesis, Connect to this title online; UW restricted, 2006. http://hdl.handle.net/1773/8489.

Full text
APA, Harvard, Vancouver, ISO, and other styles
22

Ma, Wenbo. "Transition Metal-Catalyzed C-H Functionalization for Sustainable Syntheses of Alkenes and Heterocycles." Doctoral thesis, Niedersächsische Staats- und Universitätsbibliothek Göttingen, 2015. http://hdl.handle.net/11858/00-1735-0000-0022-5FDF-4.

Full text
APA, Harvard, Vancouver, ISO, and other styles
23

Jaggar, Andrew James. "The synthesis and reactions of cationic alkyl complexes of group(IV) transition metals." Thesis, University of East Anglia, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.332355.

Full text
APA, Harvard, Vancouver, ISO, and other styles
24

DeMatteo, Matthew P. "Computational investigations of hydroxyl radical addition to aromatics and alkenes in the presence of solvent, conformational preferences of dendrimers, and theoretical studies of arabinofuranosides and septanosides." Columbus, Ohio : Ohio State University, 2007. http://rave.ohiolink.edu/etdc/view?acc%5Fnum=osu1180128001.

Full text
APA, Harvard, Vancouver, ISO, and other styles
25

Mbatha, Lancelot Lungelo Mpatho. "The synthesis, characterization and metathesis reactivity of compounds (with at least one pendant alkene group) of iron, ruthenium and iridium." Master's thesis, University of Cape Town, 2008. http://hdl.handle.net/11427/6331.

Full text
Abstract:
Includes abstract.
Includes bibliographical references.
This thesis reports on the synthesis, characterisation and metathesis reactivity studies of (i) ruthenium and iron mono(alkenyl) complexes of the type LM(COh{(CH2)nCH=CH2} (M = iron or ruthenium, L = l1s-C sHs or l1 s-CS(CH3)s and n = 2 - 6), 41 - 51; (ii) iridium complexes of the type Cp*Ir(CI)2{PPh2(CH2)mCH=CH2} (m = 2 - 4 and 6), 69 - 72; and (iii) bis(alkenyl) acyl complexes of the type CpFe(CO){C(O)(CH2)nCH=CH2}{PPh2(CH2)mCH=CH2} (n = 3 - 4, m = 3, 4 and 6), 62 - 65.
APA, Harvard, Vancouver, ISO, and other styles
26

Yang, Gang. "SYNTHESIS OF A POLYMER/ N-ALKYL UREA PEPTOID CONJUGATE." University of Cincinnati / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1380613053.

Full text
APA, Harvard, Vancouver, ISO, and other styles
27

Kovacevic, Luka Stefan. "Transfer of alkyl groups in novel amidine dications and other superelectrophiles." Thesis, University of Strathclyde, 2014. http://oleg.lib.strath.ac.uk:80/R/?func=dbin-jump-full&object_id=23158.

Full text
Abstract:
This thesis explores the synthesis and the reactivity of novel amidine salts resulting from various N-methylformamides and N-methylbenzamides I and II. Treatment of these compounds with triflic anhydride under mild conditions led to extremely facile alkyl transfer from an sp3-hybridised nitrogen centre to very weakly nucleophilic triflate anions. For the reaction pathway of substrates III and VII, in silico studies propose an equilibrium between the more stable tetrahedral triflate intermediate IV and the superelectrophilic amidinium disalt V from which dealkylation takes place. The unprecedented a-aminotriflate IV was characterised by lowtemperature 1H- and 13C-NMR spectra and the rate of alkyl transfer for substrates III and VII determined. Unlike formamides III and VII, in silico and low-temperature NMR studies of the reaction of benzamide IX with triflic anhydride showed amidinium disalt intermediate XI to be more stable than tetrahedral triflate X due to steric factors. Due to the enhanced alkyl transfer activity of amidinium disalt XV derived from benzene-based formamide XIII, low temperature NMR studies did not allow for observation of intermediates XIV or XV. However, the benzamide analogue XVII with phenyl residues on the tertiary amine allowed for isolation and characterisation of amidinium dication XVIII. The reaction protocol was subsequently applied to derivatives of 2-(alkylthio)phenylformamides XIX which underwent alkyl transfer to yield benzothiazolium salt XXII. Interestingly, benzamide analogue XXIII afforded benzthiazolium disalt XXIV upon addition of triflic anhydride, but gradually dephenylated to monocation XXV.
APA, Harvard, Vancouver, ISO, and other styles
28

Thornton, Terry L. (Terry Lee) 1962. "Mixed Alkyllithim/Lithium Alkoxide Aggregates with Less Sterically Crowded Alkyl Groups." Thesis, University of North Texas, 1997. https://digital.library.unt.edu/ark:/67531/metadc278441/.

Full text
Abstract:
Mixed alkyllithium / lithium alkoxide aggregates in the form (RLi)n(ROLi)m were formed by addition of corresponding alcohol compounds at different Li/O ratios. Variable temperature 13C and 6Li NMR spectroscopy were used to verify the formation of the mixed aggregates and to study their behavior in hydrocarbon solution. Spectra for the lithium n-propoxide / n-propyllithium and iso-butyllithium / lithium iso-butoxide systems each indicated at least one mixed aggregate.
APA, Harvard, Vancouver, ISO, and other styles
29

Poon, Suk Yue. "Synthesis, characterization and photophysics of alkynyl-derived inorganic and organometallic materials comprising group 13,14 and 16 elements." HKBU Institutional Repository, 2005. http://repository.hkbu.edu.hk/etd_ra/662.

Full text
APA, Harvard, Vancouver, ISO, and other styles
30

Sato, Takahiro. "Studies on Disilenes Bearing Alkynyl Groups and Unusual Reactivity of Overcrowded Silylene with Pyridines." 京都大学 (Kyoto University), 2012. http://hdl.handle.net/2433/157804.

Full text
APA, Harvard, Vancouver, ISO, and other styles
31

Du, Guodong. "Group 4 Metalloporphyrin diolato Complexes and Catalytic Application of Metalloporphyrins and Related Transition Metal Complexes." Washington, D.C. : Oak Ridge, Tenn. : United States. Dept. of Energy. Office of Science ; distributed by the Office of Scientific and Technical Information, U.S. Dept. of Energy, 2004. http://www.osti.gov/servlets/purl/835301-irsXCw/webviewable/.

Full text
APA, Harvard, Vancouver, ISO, and other styles
32

Shen, Lixin. "Design and synthesis of 3,3'-disubstituted-binaphthyl alkynyl boron reagents for asymmetric conjugate addition of alkynyl groups to enones and 1,2-addition to aldehydes." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 1999. http://www.collectionscanada.ca/obj/s4/f2/dsk1/tape7/PQDD_0006/NQ44782.pdf.

Full text
APA, Harvard, Vancouver, ISO, and other styles
33

Riihimäki, H. (Helena). "Substituent groups in aryl- and arylalkylphosphanes: effects on coordination chemistry and catalytic properties." Doctoral thesis, University of Oulu, 2003. http://urn.fi/urn:isbn:9514270452.

Full text
Abstract:
Abstract Thirty phosphane ligands were prepared and characterized. Aryl groups of the phosphane ligands were modified through change in functionality. The side chains were the following: trifluoromethylphenyl, selenomethylphenyl, 9-anthryl, alkyl-substituted aryl groups, and pyridyl and alkyl groups. In addition, three chromium carbonyl complexes of potentially bidentate arylphosphanes containing nitrogen heteroatoms were prepared and characterized. Characterization of the isolated complexes verified the monodentate coordination from phosphorus and two bidentate coordination modes, (P,N)-bound and (N,N')-bound. Ligands and complexes were characterized by 1H, 13C{1H}, 31P{1H}, and two-dimensional NMR spectroscopy, X-ray crystallography, and mass spectrometry. The 13C{1H} and 31P{1H} NMR spectra, and calculated cone angles of the o-alkyl-substituted aryl- and arylalkylphosphane ligands provided valuable parameters, which could be plotted against catalytic results in the search for correlations between the structures and catalytic behavior of ligands. Correlations were found between the parameters and the catalytic behavior of Rh-catalysts modified with the o-alkyl-substituted phenylphosphanes. The research reported here was directed toward the preparation and characterization of phosphane ligands which would favor the formation of isobutanal in propene hydroformylation. The o-alkyl-substituted arylphosphanes, which were studied most throughly, gave the highest selectivity to isobutanal but at the cost of activity. Linear n-butanal was still the main product, though only barely. Alkyl substituents in meta position increased the activity of propene hydroformylation even up to the level with the reference ligand PPh3, but, the selectivity decreased simultaneously.
APA, Harvard, Vancouver, ISO, and other styles
34

Carver, Colin Terrance. "Group III alkyl complexes supported by a bis-amidoferrocene ligand reactivity with N-heterocycles relevant to hydrodenitrogenation /." Diss., Restricted to subscribing institutions, 2010. http://proquest.umi.com/pqdweb?did=2023754711&sid=1&Fmt=2&clientId=1564&RQT=309&VName=PQD.

Full text
APA, Harvard, Vancouver, ISO, and other styles
35

Nishino, Noriko. "Mechanistic studies of atmospheric chemical reactions of hydroxyl radicals with aromatic hydrocarbons, including 2-ring polycyclic aromatic hydrocarbons, and terminal alkenes." Diss., UC access only, 2009. http://proquest.umi.com/pqdweb?index=94&did=1907248571&SrchMode=1&sid=1&Fmt=7&retrieveGroup=0&VType=PQD&VInst=PROD&RQT=309&VName=PQD&TS=1270251046&clientId=48051.

Full text
APA, Harvard, Vancouver, ISO, and other styles
36

He, Xiaoming, and 何晓明. "Design, synthesis and characterization of alkynyl- and thiolato-gold (I) complexes with various receptor groups for host-guestchemistry." Thesis, The University of Hong Kong (Pokfulam, Hong Kong), 2010. http://hub.hku.hk/bib/B43571979.

Full text
APA, Harvard, Vancouver, ISO, and other styles
37

Rauber, Daniel [Verfasser], and Rolf [Akademischer Betreuer] Hempelmann. "Preparation, characterization and applications of ionic liquids with perfluorinated alkyl groups / Daniel Rauber ; Betreuer: Rolf Hempelmann." Saarbrücken : Saarländische Universitäts- und Landesbibliothek, 2019. http://d-nb.info/1192754956/34.

Full text
APA, Harvard, Vancouver, ISO, and other styles
38

Rauber, Daniel Verfasser], and Rolf [Akademischer Betreuer] [Hempelmann. "Preparation, characterization and applications of ionic liquids with perfluorinated alkyl groups / Daniel Rauber ; Betreuer: Rolf Hempelmann." Saarbrücken : Saarländische Universitäts- und Landesbibliothek, 2019. http://d-nb.info/1192754956/34.

Full text
APA, Harvard, Vancouver, ISO, and other styles
39

He, Xiaoming. "Design, synthesis and characterization of alkynyl- and thiolato- gold (I) complexes with various receptor groups for host-guest chemistry." Click to view the E-thesis via HKUTO, 2010. http://sunzi.lib.hku.hk/hkuto/record/B43571979.

Full text
APA, Harvard, Vancouver, ISO, and other styles
40

Paige, Danny R. "The synthesis, co-ordination chemistry and catalytic applications of phosphine ligands containing long-chain perfluoro-alkyl groups." Thesis, University of Leicester, 1998. http://hdl.handle.net/2381/30022.

Full text
Abstract:
A review is presented of the use of catalytic liquid-liquid biphase systems containing a perfluorinated phase, commonly referred to as 'fluorous biphase systems' or F.B.S. catalysis. The phosphines PPh(3-x)(C2H4C6F13), PPh(3-x)(C6H4-p-C6F13)x and PPh(3-x)(C6H4-m-C6F13), where x = 1, 2 and 3, have been synthesised and fully characterised by 1H, 19F and 31P NMR spectroscopy, mass spectroscopy and elemental analysis, with a view to assessing their potential for use in F.B.S. catalysis. The crystal structures of O=P(C6H4-m-C6F13) and Cl-P(C6H4-o-C6F13)2 are also reported. The synthetic route to P(C2H4C6F13)3 represents an improvement on the literature preparation. These phosphines have been reacted with a variety of transition metals to form complexes of the type cis- and trans-[MCl2L2] (M = Pt, Pd), trans-[MCl(CO)L2] (M = Rh, Ir), [RhCp*Cl2L] and [RhClL3]. These complexes have all been isolated and fully characterised, except for the complexes [RhClL3], which have not been isolated, but whose solution chemistry is described. The crystal structures of the complexes cis-[PtCl2(PPh2C2H4C6F13)2] and trans-[RhCl(CO)(P{C2H4C6F13}3)2] are also reported. All of the complexes described above have been extensively investigated using a variety of analytical techniques including 31P, 19F and 1H NMR spectroscopy, mass spectroscopy and IR spectroscopy. The results from an EXAFS spectroscopic study on some of these complexes is included as an appendix to this work. The electronic and steric influence of the perfluorinated chains on the reactivity and behaviour of both the free phosphines and the metal complexes has been evaluated from the nature of the products isolated, from a comparison of their spectroscopic and structural data with those for related metal-phosphine complexes and, for the complexes trans-[IrCl(CO)L2], from a kinetic study on the rate of O2 addition. Preliminary catalytic hydrogenation and hydroformylation studies have been carried out using the complexes [RhClL3] and [RhH(CO)L3] respectively, where L = phosphine. These catalytic species were gathered in situ and the study involved the use of F.B.S. catalysis. The effect of the variation of the phosphine type, the solvents and the reaction conditions, has been examined in terms of reaction rate, product selectivity and product/catalyst separation. The potential of F.B.S. catalysis using phosphine ligands has been assessed.
APA, Harvard, Vancouver, ISO, and other styles
41

Valverde, Ibai. "La multi-ligation triazole : développement de nouveaux outils pour la synthèse de mimes de protéines par cycloadditions successives." Thesis, Orléans, 2010. http://www.theses.fr/2010ORLE2010.

Full text
Abstract:
Ce travail est consacré au développement d’une nouvelle méthode de synthèse d’analogues bioactifs de protéinesen utilisant des réactions successives de cycloaddition entre les alcynes terminaux et les azotures (CuAAC).Pour pouvoir effectuer des cycloadditions itératives, nous avons étudié la stabilité et les conditions de coupure dedifférents groupements masquants des alcynes terminaux. Cette étude a été valorisée par le développement d’unestratégie originale pour réaliser un triple cycloaddition successive une même molécule basée sur la protectiontemporaire de la fonction alcyne.La méthode a été appliquée à la synthèse d'un analogue de la stéfine A humaine, un inhibiteur naturel deprotéases à cystéine d’intérêt thérapeutique. Pour cela, nous avons mis au point des conditions de CuAACsuccessive compatibles avec des peptides déprotégés de façon beaucoup à obtenir in fine un analogue bis-triazolede la stéfine A. Les études par dichroïsme circulaire et d’inhibition de diverses protéases à cystéines confirmentque notre analogue synthétique conserve la structure et l’activité biologique de la protéine native.La stratégie de ligation triazole successive a été étendue par la mise au point de conditions pour réaliser desligations sur phase solide. La méthodologie développée permet la synthèse de protéines de façon plus rapide etplus simple que par des procédés classiques de ligation successive en solution. Dans l’optique de la synthèse destructures glycopeptidiques capables d’induire une réponse immunitaire contre MUC1 tumorale, nous avons réaliséla synthèse d’analogues peptidiques de MUC1 par ligation successive sur phase solide de 160 acides aminés
The aim of this work was the development of a novel method for the synthesis of triazolo-proteins by multiplesuccessive copper-catalyzed azide-alkyne cycloadditions (CuAAC).In order to achieve several successive cycloadditions, we have studied the stability and cleavage conditions ofseveral alkyne protective groups. This study leaded us to the development of an original strategy in order toachieve three successive cycloadditions on a same scaffold by temporal protection of alkyne functionalities.The method has been applied to the synthesis of an analogue of human stefin A, a natural inhibitor of severaltherapeutically relevant cysteine proteases. Therefore, we have developed CuAAC conditions compatible withunprotected peptide ligation. The strategy allowed us to obtain a bis-triazolo analogue of human stefin A. Circulardichroism and enzymology assays on several cysteine cathepsins revealed that the synthetic analogue hasretained the folding and full biological activity of the native protein.In order to expand the possibilities of this strategy, we have developed reaction conditions allowing us to performsuccessive triazole ligation on solid phase. This methodology avoids the need for a time-consuming and laborintensivepurification step before and after each ligation. With the aim of exploring the use of analogues of thetumor-associated form of the glycoprotein MUC1 to induce a specific immune response, we have synthesized atriazolo-analogue of MUC1 of 160 aminoacids using solid phase peptide ligation
APA, Harvard, Vancouver, ISO, and other styles
42

KALAM-ALAMI, MAHMOUD MOUS. "Etude de la reactivite stoechiometrique ou catalytique de clusters de metaux de transition du groupe 8." Toulouse 3, 1987. http://www.theses.fr/1987TOU30017.

Full text
APA, Harvard, Vancouver, ISO, and other styles
43

Khan, Rana Kashif. "New Concepts, Catalysts, and Methods in Stereoselective Olefin Metathesis." Thesis, Boston College, 2014. http://hdl.handle.net/2345/bc-ir:104359.

Full text
Abstract:
Thesis advisor: Amir H. Hoveyda
Chapter 1. Mechanistic Insights and Factors Influencing Polytopal Rearrangements in Stereogenic-at-Ru Carbenes. Herein, the mechanistic elucidation of the stereochemical inversion in stereogenic-at-Ru carbene complexes through olefin metathesis (OM) and non-olefin metathesis (non-OM) based polytopal rearrangements is provided. Our investigations involve the isolation and characterization of previously hypothesized higher-energy (e.g., endo-anti) and lower-energy (e.g., exo-anti) diastereomers, and their interconversion under thermal and/or acid-catalyzed conditions is demonstrated. Furthermore, our computational efforts highlighting the importance of the anionic ligands, due to their critical role in trans influence, dipolar interactions, and e-e repulsions, in polytopal rearrangements are reported. Finally, the positive influence of H-bonding in OM and non-OM processes is also rationalized. (a) Khan, R. K. M.; Zhugralin, A. R.; Torker, S.; O'Brien, R. V.; Lombardi, P. J. and Hoveyda, A. H. "Synthesis, Isolation, Characterization, and Reactivity of High-Energy Stereogenic-at-Ru Carbenes: Stereochemical Inversion Through Olefin Metathesis and Other Pathways," J. Am. Chem. Soc. 2012, 134, 12438-12441. (b) Torker, S.; Khan, R. K. M. and Hoveyda, A. H. "The Influence of Anionic Ligands on Stereoisomerism of Ru Carbenes and Their Importance to Efficiency and Selectivity of Catalytic Olefin Metathesis Reactions," J. Am. Chem. Soc. 2014, 136, 3439-3455. Chapter 2. Highly Z- and Enantioselective Ring-Opening/Cross-Metathesis of Enol Ethers Through Curtin-Hammett Kinetics. The first instances of Z- and enantioselective Ru-catalyzed olefin metathesis are presented. Ring-opening/cross-metathesis (ROCM) reactions of oxabicyclic alkenes and enol ethers and a phenyl vinyl sulfide are promoted by 0.5-5.0 mol % of enantiomerically pure stereogenic-at-Ru complexes with an aryloxy chelate tethered to the N-heterocyclic carbene. Products are formed efficiently and with exceptional enantioselectivity (up to >98:2 enantiomer ratio). Surprisingly, the enantioselective ROCM reactions proceed with high Z selectivity (up to >98% Z). Moreover, reactions proceed with the opposite sense of enantioselectivity versus aryl olefins, which afford E- isomers exclusively. DFT calculations and deuterium-scrambling experiments, indicating fast interconversion between endo- and exo-Fischer carbene diastereomers, support a Curtin-Hammett situation. On this basis, models accounting for the stereoselectivity levels and trends are provided. Furthermore, the correlation of Fischer carbene character to the observed chemoselectivity in ROCM with enol ethers is also disclosed. Finally, a general proposal for the substrate-controlled Z selectivity in OM is also discussed. (a) Khan, R. K. M.; O'Brien, R. V.; Torker, S.; Li, B. and Hoveyda, A. H. "Z- and Enantioselective Ring-Opening Cross-Metathesis with Enol Ethers Catalyzed by Stereogenic-at-Ru Carbenes: Reactivity, Selectivity, and Curtin-Hammett Kinetics," J. Am. Chem. Soc. 2012, 134, 12774-12779. (b) Torker, S.; Koh, M. J.; Khan, R. K. M. and Hoveyda, A. H. "Origin of Z selectivity in Olefin Metathesis Reactions of Certain Terminal Alkenes Catalyzed by Typically E-Selective Ru Carbenes," manuscript submitted. Chapter 3. A New Class of Highly Efficient Ru Catalysts for Z-Selective Olefin Metathesis. Herein, we outline a general design for Z-selective OM, which led to the development of a new class of stereogenic-at-Ru carbene complexes (Ru4-9). Furthermore, we demonstrate that the newly developed dithiolate complexes Ru4b and Ru5 efficiently promote high activity and selectivity in ROMP reactions of norbornene and cyclooctene. Notably, the catechothiolate Ru4b catalyzes Z-selective ROCM with a broad scope of alkenes involving various functional groups (e.g., alcohols, enol ethers, vinyl sulfides, amides, heterocycles, and conjugated 1,3-dienes). More importantly, we disclose that the catecholate complex Ru4a is kinetically non-selective in OM and readily decomposes in the presence of mildly acidic moieties (e.g., alcohols and CDCl3). Subsequently, Ru9 is developed to efficiently promote highly Z-selective CM of a diol cross-partner with a wide range of alkene substrates. Most remarkably, the aforementioned protocol is employed in two natural product syntheses and the OM-based Z-selective cracking of oleic acid, which is unprecedented with existing Ru-carbenes and Mo/W-alkylidenes. (a) Khan, R. K. M.; Torker, S. and Hoveyda, A. H. "Readily Accessible and Easily Modifiable Ru-Based Catalysts for Efficient and Z-Selective Ring-Opening Metathesis Polymerization and Ring-Opening Cross-Metathesis," J. Am. Chem. Soc. 2013, 135, 10258-10261. (b) Koh, M. J.; Khan, R. K. M.; Torker, S. and Hoveyda, A. H. "Broadly Applicable Z- and Diastereoselective Ring-Opening/Cross-Metathesis Catalyzed By a Dithiolate Ru Complex," Angew. Chem., Int. Ed. 2014, 53, 1968-1972. (c) Khan, R. K. M. ; Torker, S. and Hoveyda, A. H. "Reactivity and Selectivity Differences Between Catecholate and Catechothiolate Ru Complexes. Implications Regarding Design of Stereoselective Olefin Metathesis Catalysts," J. Am. Chem. Soc. 2014, 136, 14337-14340. (d) Koh, M. J.; Khan, R. K. M.; Torker, S.; Yu, M.; Mikus, M. S. and Hoveyda, A. H. "Synthesis of High-Value Alcohols, Aldehydes and Acids by Catalytic Z-Selective Cross-Metathesis" manuscript submitted
Thesis (PhD) — Boston College, 2014
Submitted to: Boston College. Graduate School of Arts and Sciences
Discipline: Chemistry
APA, Harvard, Vancouver, ISO, and other styles
44

Tena, Emmanuel. "Chimie organométallique de surface sur métaux de composés du groupe XIV fonctionnalisés sur des chaînes alkyles : application à l'hydrogénation catalytique de substrats insaturés fonctionnels." Lyon 1, 1996. http://www.theses.fr/1996LYO10233.

Full text
Abstract:
Ce travail est consacre a l'etude de systemes bimetalliques generes par voie coms comportant des fragments alkyles de surface fonctionnalises. La presence d'une fonction sur le fragment de surface devant permettre de preparer des catalyseurs sur mesure ayant des selectivites particulieres par effets steriques, electroniques ou electrostatiques dus aux ligandes de surface. La premiere etape de cette etude a ete consacree a la synthese de precurseurs organometalliques de l'etain et du germanium fonctionnalises sur des chaines alkyles. Plusieurs types de composes ont pu etre synthetises: alkyles mixtes ou homoleptiques de l'etain, hydrures d'etain et du germanium. L'interaction de ces composes a ete menee en presence de solvant sur des surfaces de rhodium et de platine. Dans tous les cas, des fragments organometalliques de surface fonctionnels sont conserves. L'etat des especes de surface fonctionnelles depend du type de precurseur utilise, du metal et du solvant. Le trihydrure de germanium fonctionnel h#3ge-(ch#2)#4-oh est le compose le plus prometteur. Afin de caracteriser les especes obtenues par interaction de h#3ge-(ch#2)#4-oh sur les surfaces metalliques, l'hydrogenolyse de ce compose a ete menee sans solvant. Les methodes physiques suivantes ont ete utilisees: volumetrie de degagements gazeux, spectroscopie infra-rouge, exafs. Des especes de surface de formules globales mgeh#x-(ch#2)#4-oh (m=rh ou pt, 1
APA, Harvard, Vancouver, ISO, and other styles
45

Cushion, Michael Gregory. "New main group and rare earth complexes and their applications in the ring-opening polymerisation of cyclic esters." Thesis, University of Oxford, 2011. http://ora.ox.ac.uk/objects/uuid:b5041775-575f-46bb-9f52-dc3417e76cca.

Full text
Abstract:
This Thesis describes the synthesis and characterisation of new Main Group and Rare Earth alkyl, amide, alkoxide and borohydride complexes and their use as catalysts for the ring-opening polymerisation (ROP) of ε-caprolactone and rac-lactide. Chapter 1 introduces ROP from an industrial and academic perspective, as well as polymer characterisation techniques. A literature review is given, with an emphasis placed on Main Group catalysts. Chapter 2 describes the synthesis and characterisation of new homo- and hetero-scorpionate Main Group complexes. An introduction to homo- and hetero-scorpionate ligands is given, as well as a discussion of the ε-caprolactone and rac-lactide ROP activity displayed by the new complexes. Chapter 3 describes the synthesis and characterisation of new neutral and cationic Main Group borohydride complexes supported by the tris(pyrazolyl)methane and tris(pyrazolyl)hydroborate ligands. A review of borohydride complexes is also given. The ε-caprolactone and rac-lactide ROP activity shown by the complexes presented is also discussed. Chapter 4 describes the synthesis and characterisation of new mono- and di-cationic yttrium complexes supported by the tris(pyrazolyl)methane and triazacyclononane ligands. An introduction to the synthesis of neutral and cationic Rare Earth complexes is given. An overview of immortal ROP is also provided. The activity of the new complexes towards the immortal ROP of rac-lactide is also discussed. Chapter 5 contains experimental details and characterising data for the new complexes reported in this thesis. CD Appendix contains .cif files for all of the new crystallographically characterised complexes.
APA, Harvard, Vancouver, ISO, and other styles
46

Buriez, Olivier. "Activation electrochimique de complexes organonickel (ii) de type cpni(l)ch2y, avec l ligand phosphine et y groupe partant alkyl, sulfonyl, ou soufre." Paris 7, 1996. http://www.theses.fr/1996PA077180.

Full text
Abstract:
Le travail realise s'inscrit dans le cadre d'une approche mecanistique de l'activation, par des sels de nickel, de carbanion stabilises. Dans cette approche, nous avons etudie l'activation par transfert monoelectronique de composes organonickel du type cp(l)nichry (y groupe partant nucleofuge, cp et l ligands cyclopentadienyle et phosphine) qui sont des modeles d'especes intermediaires intervenant dans de tels processus. Des etudes par voltametrie cyclique des complexes cationiques (cpnil#2)#+ et chlores cpni(l)cl, ont permis, tout d'abord, de mettre en evidence, de determiner le domaine de stabilite et de caracteriser le comportement electrochimique de radicaux du nickel(i) a dix-sept et dix-neuf electrons. Une seconde reduction conduit a un anion nickelate possedant un fort caractere nucleophile vis a vis des electrophiles stanyles. La reduction des complexes alkylnickel apparentes cpni(l)r conduit a la coupure de la liaison carbone-nickel avec formation de ce meme anion nickelate. Ces premiers resultats nous ont permis d'aborder ensuite l'etude des composes cp(l)nichry plus riches en sites reactionnels. L'activation par transfert monoelectronique de tels complexes permet de distinguer trois types de comportement limite dependant du groupe partant y: une coupure de la liaison carbone-nickel (groupe partant sulfone), un processus de reduction bielectronique avec coupure de la liaison carbone-soufre conduisant a un complexe carbenique anionique (groupe partant alkylthio), et une coupure de la liaison carbone-soufre a un electron conduisant a un complexe carbenique neutre (groupe partant sulfonium). Enfin, des etudes visant a mettre en evidence une eventuelle cyclopropanation des olefines non-activees par ces complexes carbeniques ont ete effectuees
APA, Harvard, Vancouver, ISO, and other styles
47

Bentahar, Fatima Zohra. "Etude de la réactivité de composés alkyls, alcoolates et carboxylates d'étain tributyle avec les surfaces de platine et de palladium supportés sur silice, alumine ou charbon : application des catalyseurs bimétalliques obtenus à la déshydrogénation de l'isobutane en isobutène." Lyon 1, 1997. http://www.theses.fr/1997LYO10078.

Full text
Abstract:
Il a ete montre au laboratoire que des catalyseurs bimetalliques platine-etain prepares par reaction entre le tetrabutyletain et la surface reduite du platine presentaient de remarquables proprietes, tant de selectivite que d'activite ou de stabilite dans la deshydrogenation de l'isobutane en isobutene. Jusqu'a present, cette methode de preparation developpee au laboratoire sous le nom de chimie organometallique de surface sur metaux (coms/m) a ete mise en oeuvre dans un alcane, milieu dans lequel le tetrabutyletain est soluble. Dans le but de banaliser cette methode de preparation de catalyseurs bimetalliques en vue de son application a l'echelle industrielle, nous nous sommes fixe comme objectif, l'utilisation de l'eau comme solvant. Les derives tetra-alkyles de l'etain (r#4sn) ne sont pas solubles dans l'eau, par contre, les derives alcoolates (r#3snor') sont solubles dans les alcools et nous avons montre que le tributyletain-acetate (bu#3snoc(o)me) se solubilisait sous forme de tributyletain-hydroxyde (bu#3snoh) en milieu aqueux basique (ph10). Des catalyseurs monometalliques (m=pt et pd) hotes supportes sur alumine, sur silice et sur charbons ont ete prepares et caracterises par differentes techniques. L'interaction de r#4sn, r#3snor' et r#3snoh sur ces catalyseurs reduits a ete etudiee en detail, dans un alcane (r#4sn), dans un alcool (r#3snor') et dans l'eau (r#3snoh). Dans les trois cas, la reaction a pris place uniquement sur la surface du metal hote, avec formation d'une espece de surface partiellement desalkylee de la forme m#ssnr#x#y. Il a ete montre que la valeur de x dependait du taux de recouvrement (y) de la surface metallique, de la nature et de la taille des particules metalliques. Par traitement sous hydrogene a 500c, ce complexe perd la totalite de ces groupement alkyles pour donner un catalyseur bimetallique de composition parfaitement homogene. Testes dans la deshydrogenation de l'isobutane, tous les echantillons, prepares en milieu organique ou aqueux ont presente la meme activite et la meme selectivite en isobutene, validant ainsi la faisabilite de la methode coms/m dans l'eau.
APA, Harvard, Vancouver, ISO, and other styles
48

Poutrel, Pauline. "Réduction du motif vinyl-CF₃ : vers la synthèse catalytique énantiosélective de centres C-CF₃ et la synthèse diastéréosélective de monofluoroalcènes terminaux Copper‐catalyzed enantioselective formation of C−CF3 centers from β‐CF3‐substituted acrylates and acrylonitriles Stereoselective synthesis of terminal monofluoroalkenes from trifluoromethylated alkenes." Thesis, Normandie, 2020. http://www.theses.fr/2020NORMIR07.

Full text
Abstract:
Ces dernières années, la chimie du fluor est devenue un domaine clé de recherche de par la présence croissante de l’atome du fluor dans les molécules issues de l’agrochimie, de l’industrie pharmaceutique et des matériaux. Il est alors nécessaire de développer de nouvelles méthodologies permettant la synthèse de ces molécules fluorées. Dans notre cas, il s’agit de mettre au point des procédures permettant l’obtention de synthons d’une part avec un centre stéréogène contrôlé comportant un motif trifluorométhyle, d’autre part avec un motif monofluoroalcène terminal. Dans un premier temps, nous avons développé une méthodologie pour la réduction catalytique asymétrique d’acrylates et d’acrylonitriles β-CF3 via la formation in-situ d’un hydrure de cuivre chiral. Dans un second temps, avons mis au point une méthodologie de synthèse de monofluoroalcènes terminaux par réduction au LiAlH4 d’acrylates β-CF3 et de styrènes α-CF3 di-, tri- ou tétrasubstitués
In recent years, organofluorine chemistry has become a key field of research thanks to the growing presence of the fluorine atom in molecules coming from agrochemistry, pharmaceutical industry and materials. It is therefore necessary to develop new methodologies for the synthesis of fluorinated molecules. In our case, we envisioned to develop procedures to obtain synthons with a stereogenic center bearing a trifluoromethyl group on the one hand, and synthons with a terminal monofluoroalkene motif on the other hand. We first developed a methodology for the catalytic asymmetric reduction of β-CF3 acrylates and acrylonitriles via the formation in-situ of a chiral copper hydride species. We then developed a methodology for the synthesis of terminal monofluoroalkenes by reduction of di-, tri- or tetrasubstitued β-CF3 acrylates and α-CF3 styrenes with LiAlH4
APA, Harvard, Vancouver, ISO, and other styles
49

Henklein, Petra. "N alpha -Arensulfonyl-Aminosäurechloride." Doctoral thesis, Humboldt-Universität zu Berlin, Mathematisch-Naturwissenschaftliche Fakultät I, 2000. http://dx.doi.org/10.18452/14600.

Full text
Abstract:
Obwohl die methodische Entwicklung der Peptidsynthese gewöhnlich eine automatisierte Herstellung erlaubt, sind für die Herstellung einer Reihe von Peptiden auch gegenwärtig Grenzen gesetzt. Einerseits kann eine im Verlauf der Kettenverlängerung auftretende Bildung intra- und /oder intermolekularer Wasserstoffbrücken zu einer begrenzten Solvatation und damit Zugänglichkeit der zu acylierenden Aminokomponente am Syntheseharz führen, andererseits kommt es beim Einbau sterisch anspruchsvoller Aminosäuren zu ungenügenden Acylierungsausbeuten. Urethangeschützte Aminosäurefluoride haben sich für den Einbau von alpha, alpha-Dialkylaminosäuren als geeignet erwiesen. Die reaktiveren urethangeschützten Aminosäurechloride sind zwar herstellbar, besitzen aber in Gegenwart einer Hilfsbase, die zum Abfangen der während ihrer Reaktion gebildeten HCl notwendig ist, eine zu geringe Stabilität (Oxazolonbildung, Abspaltung der Schutzgruppen). Erst die Verwendung von N(alpha)-Schutzgruppen, die keinen reaktionsfähigen Carbonylkohlenstoff enthalten, wie Arensulfonyl- Schutzgruppen, ermöglichen die volle Ausschöpfung der hohen Reaktivität der Aminosäurechloride. Mit Hilfe dieser Schutzgruppen gelang ein erster Vergleich der Reaktivität der Aminosäurechloride und -fluoride. Bei den durchgeführten Reaktionen wurde keine Stereomutation beobachtet. Unter Verwendung von Arensulfonylschutzgruppen war es erstmals möglich, zwei aufeinanderfolgende N-Alkyl-alpha, alpha-dialkylaminosäuren in Peptide einzubauen. Weiterhin konnten wir zeigen, daß derart geschützte Aminosäuren sich für in situ Aktivierungen mit Thionylchlorid eignen. Als Fänger für überschüssiges Aktivierungsreagenz wurden tertiäre Alkohole bzw. Amine eingesetzt. Arensulfonyl-geschützte Aminosäurechloride haben wir darüber hinaus erfolgreich in der Festphasenpeptidsynthese verwendet. In Kombination von Arensylfonyl-Schutz mit der Standard-Fmoc-Strategie gelang die Synthese eines biologisch aktiven Analogen des CRF, eines 41-mer Peptides mit einer eingefügten Tetrapeptidsequenz -Ala-MeAib-MeAib-Aib-.
Despite its wide field of application automatic peptide synthesis is still limited in certain cases. One of the limiting factors is the possibility of intra- or intermolecular hydrogen bond formation during the elongation of the peptide chain. This causes decreased solvation and thus reduced accessibility to the resin-bound amino component. Another limitation is the incorporation of sterically hindered amino acids that usually give rise to insufficient yields of acylation. Urethane protected amino acid fluorides have been shown suitable for the incorporation of alpha,alpha-dialkyl amino acids. Though the more reactive urethane protected amino acid chlorides can be readily synthesized, they do not possess the necessary stability in the presence of an auxiliary base that must be used for trapping of the hydrochloric acid formed during the reaction. Formation of oxazolons and deprotection of formerly protected functional groups would occur. Only the advent of protecting groups for the amino acid N-alpha that do not have a reactive carbonyl function - like arene sulfonyl groups - allowed to take full advantage of the high reactivity of the amino acid chlorides. These protecting groups enabled us to compare the reactivities of amino acid chlorides and fluorides for the first time. We didn't observe any stereo mutation in our experiments. The use of arene sulfonyl protecting groups permitted the consecutive incorporation of two N-alkyl-alpha,alpha-dialkyl amino acids into a peptide for the first time. Furthermore we could show, that amino acids protected in this way, are suitable for in situ activation with thionyl chloride. Tertiary alcohols and amines were used as scavenger for excessive activating reagent. Arene sulfonyl protected amino acids were also successfully used in solid phase peptide synthesis. By combining this protecting concept with the standard Fmoc approach we were able to synthesize a biologically active analogue of CRF, a peptide containing 41 residues into which we inserted the tetrapeptide Ala-MeAib-MeAib-Aib.
APA, Harvard, Vancouver, ISO, and other styles
50

Figadère, Bruno. "Les composes organomanganeux mixtes : addition 1-2 selective sur des aldehydes ou des cetones portant un groupe fonctionnel, enolisation regioselective de cetones : application en synthese." Paris 6, 1987. http://www.theses.fr/1987PA066371.

Full text
Abstract:
Les reactifs organomanganeux rmnx(x=cl, br, i; r=n-, sec- t-alkyl, alcenyl, aryl, alcynyl) s'additionnent aux aldehydes et cetones fonctionnels pour donner selectivement les alcools correspondant avec d'excellents rendements. Les reactifs rmnz(z=nphme) enolisent les cetones avec une excellente regioselectivite. Les enolates manganeux ainsi prepares sont tres aisement acyles, silyles, alkyles, hydroxyalkyles, avec des rendements de 60% a 90%, a la temperature ambiante
APA, Harvard, Vancouver, ISO, and other styles
You might also be interested in the bibliographies on the topic 'Alkyne group' for other source types:
Journal articles
We offer discounts on all premium plans for authors whose works are included in thematic literature selections. Contact us to get a unique promo code!

To the bibliography