Au cours des dernières années, la synthèse ciblée du butadiène en utilisant le bioéthanol a suscité une attention sans précédent en raison de l'intérêt croissant aux matières premières biosourcées ainsi que de la demande croissante en butadiène.Un processus pertinent dans ce contexte est le processus d'Ostromyslensky, qui s’effectue en deux étapes, comprenant la déshydrogénation de l'éthanol en acétaldéhyde en une étape séparée , suivie de la production de butadiène dans la deuxième étape par réaction d'acétaldéhyde avec de l'éthanol supplémentaire. Bien que la viabilité économique et la faisabilité de ce procédé d’éthanol en butadiène (ETB) soient bien établies, il reste de la place pour de meilleures performances catalytiques et une meilleure sélectivité. Dans cet effort, notre objectif était de développer une famille de catalyseurs sur silice à base de silice bien définis, basés sur la chimie organométallique de surface (SOMC) et de les tester lors de la conversion d'EtOH / AA en BD. Le premier ensemble de pré-catalyseurs a été synthétisé en traitant le [(=SiO)2TaHx] précédemment connu avec du N2O en tant qu'oxydant doux. La deuxième famille de catalyseurs a été préparée par calcination de l'espèce alkyl de tantale à 500°C. Les pré-catalyseurs ont été caractérisés par FTIR, RMN SS, UV-vis-DRS, DRX, EXAFS et HR-STEM. On a découvert que les pré-catalyseurs SOMC oxydés au N2O avaient principalement isolé des espèces [(SiO)2Ta (OH)x] peuplant la surface, tandis que la famille des pré-catalyseurs synthétisés par calcination mettait en évidence un mélange d’espèces de surface, y compris des agrégations de type cordes. Les tests catalytiques sur ces catalyseurs ont donné des résultats prometteurs, présentant une catalyse supérieure dans la transformation d'EtOH / AA en BD en termes de sélectivité en BD et de rendement par rapport à l'état de la technique. Outre l'excellente sélectivité, une gamme étroite de distribution du produit et une formation négligeable de coke ont été observées. Les espèces de TaOx isolées sur le pré-catalyseur oxydé au N2O ont montré une activité nettement meilleure et se sont révélées être les sites actifs de cette conversion par rapport à l'agrégation en chaîne de centres de tantale sur le matériau calciné. Sur la base de ces études DRIFT et in situ sur les catalyseurs, un mécanisme préliminaire pour cette conversion a été proposé / In the recent years on-purpose synthesis of butadiene using bioethanol has gained unprecedented attention owing to rise in interest for bio-based feedstock along with the steeply increasing demand for butadiene (BD). In this regard a relevant process is the Ostromyslensky’s two-step process, involving dehydrogenation of ethanol to acetaldehyde in a separate step, followed by butadiene production in the second stage by co-feeding ethanol and acetaldehyde. Although the economic viability and feasibility of this ethanol to butadiene (ETB) process is well established, there is a room for better catalytic performances and selectivity. In this endeavour our aim was to develop a family of well-defined Ta-based silica-supported catalysts through Surface Organometallic Chemistry (SOMC) and test them in the conversion of EtOH/AA to BD. The first set of pre-catalysts was synthesized by treating the previously known [(=SiO)2TaHx] with N2O as mild oxidant. The second family of catalysts was prepared by calcination of the tantalum alkyl species at 500°C. The pre-catalysts were characterized by FTIR, SS NMR, UV-vis-DRS, XRD, EXAFS and HR-STEM. The N2O oxidized SOMC pre-catalysts were found to have mostly isolated [(=SiO)2Ta(OH)x] species populating the surface whereas the family of pre-catalysts synthesized via calcination evidenced a mixture of surface species, including string-like aggregations.Catalytic tests over these catalysts generated promising results exhibiting superior catalysis in the transformation of EtOH/AA to BD in terms of both BD selectivity and yield compared to the state of the art. In addition to the excellent selectivity a narrow range of product distribution and negligible coke formation was observed. Isolated TaOx species on the N2O oxidized pre-catalyst showed markedly better activity and were found to be the active sites in this conversion compared to the string-like aggregation of tantalum centres on the calcined material. Based on this and in-situ DRIFT studies over the catalysts a preliminary mechanism for this conversion was proposed

Au cours de cette thèse, nous avons synthétisé de nouveaux composés en utilisant des macrocycles de porphyrines comme socle pour nos architectures. L'objectif était d'étudier leurs propriétés en optique linéaire et non linéaire. Plus précisément, nous avons synthétisé et caractérisé trois groupes de dendrimères de type fluorényl-porphyrine, une série de porphyrines organométalliques dérivés du ruthénium, et commencé une dernière série de nouvelles porphyrines. Les corrélations entre les propriétés et la structure ont été étudiés, le processus de transfert d'énergie du donneur vers la porphyrine a aussi été évalué. En introduction, nous avons présenté le contexte général de la chimie des porphyrines basé sur quatre aspects: (1) la structure chimique, (2) les voies de synthèse, (3) les propriétés en optique linéaire (4) et en optique non linéaire. Nous avons ensuite présenté les différents travaux qui ont été effectués dans notre groupe, et conclut en proposant de nouvelles structures basées sur ces résultats. Dans le premier chapitre, nous présentons la synthèse d'un groupe de dendrimères dérivés de thiényl-porphyrines. Les unités thiényles font le pont entre les dendrons conjugués de type fluorényle et le coeur de la porphyrine. Le transfert d'énergie pour ces molécules est efficace et ces dernières présentent des propriétés en optique non linéaire qui sont intéressantes avec une amélioration de l'absorption à deux photons (ADP). Dans le deuxième chapitre, nous présentons la synthèse d'une série de composés à base de ruthénium dérivés de la Tétrafluorényl- porphyrine (TFP), pour des applications en optique non linéaire (üNL). Dans le troisième chapitre, nous présentons la synthèse de deux nouveaux dendrons avec des antennes fluorényles terminales greffées en position 9 d'un troisième fluorényle, respectivement par voie conjuguées ou non conjuguées. Puis deux nouveaux dendrimères ont été obtenus par couplage de Sonogashira à partir de ces dendrons sur le coeur porphyrine TFP. Le transfert d'énergie de ces dendrons vers la porphyrine est efficace. Ces molécules présentent des propriétés en optique non linéaire qui sont intéressantes et les résultats en ADP sont très prometteurs. Dans le quatrième chapitre, nous présentons la synthèse de porphyrines avec des bras fluorénones terminales. Ces porphyrines émettent également une luminescence rouge et le transfert d'énergie est très efficace. Comme perspectives, un nouveau type de porphyrine méso-alcynyle est envisagé, pour l' instant nous avons juste synthétisé la génération 0 de cette série de dendrimères: Les quatre bras tluorényles sont pontés au coeur de la porphyrine avec des liens alcynyles, et les études optiques de ces prototypes sont en cours. / During this thesis, we have elaborated new compounds using the porphyrin macrocycle as the basic platform of our architectures. The aim, after their syntheses, was to study the linear optical (LO) and non-linear optical (NLO) properties of these new molecules. More precisely, we have synthesized and characterized three groups of fluorenyl-porphyrin dendrimers, a series of ruthenium organometallic porphyrins, and started a series of new type of porphyrin. Their correlations on optical property-structure have been discussed, as well as the energy transfer processes from the donor fragments to porphyrin core acceptor. In the introduction, we presented the general background of the porphyrin chemistry based on four aspects: ( I) structure, (2) synthetic methods, (3) LO properties and (4) NLO properties. We further reviewed prior porphyrin studies done in our group and proposed new molecular designs based on these results. In the first chapter, we synthesized a group of thienyl porphyrin cored dendrimers. The thienyl units connect the conjugated fluorenyl dendrons to porphyrin ring by alkynyl bridges. The energy transfer (ET) of these porphyrins is very efficient and they present interesting NLO properties with enhanced Two-photon absorption (TPA). In the second chapter, we synthesized a series of ruthenium compounds based on Tetra-fluorenyl porphyrin core (TFP) for NLO applications. In the third chapter, we synthesized two new dendrons with two terminal fluorenyl antennae fi xed on the 9 position of the fluorenyl units in conjugated or non-conjugated way respecti vely. Then two new porphyrin dendrimers were obtained by Sonogashira coupling reaction of these dendrons on TFP porphyrin core. Their ET from dendrons to porphyrin core is very efficient. They present interesting LO properties and the TPA results are very promising. In the fourth chapter, we synthesized a group of TFP cored porphyrins with terminal fluorenone anns. These porphyrins emit red luminescence and the ET is very efficient from the linear arms toward their cores. As perspective, a new type of meso-alkynyl porphyrin series is considered, for the moment we synthesized only the generation 0 of the dendrimers: the four fluorenyl arms of this porphyrin are bridged to the centre ring by alkynyl chains, and the optical studies of this prototype are in progress.

We report here the development of a Lewis acid catalyzed method for the dehydrative coupling of cyclic alcohols and nitriles to form amides with retention of configuration. By contrast, the formation of amides by nitrile trapping of carbocations (Ritter reaction) usually affords racemic product. The present reaction was accomplished by first converting alcohol starting materials to their corresponding chlorosulfites in situ. Even after an extensive search, only copper (II) salts were able to produce the desired conversion of these chlorosulfites to amides though with low catalytic turnover. Improving the turnover without deteriorating the stereochemical outcome was eventually accomplished by a careful selection of the reagent addition sequence and through the removal of gaseous byproducts. This Ritter-like coupling reaction proceeds in good yields with secondary cyclic alcohols under mild conditions. The stereochemical outcome likely due to fast nucleophilic capture of a non-planar carbocations (hyperconjomers) stabilized by ring hyperconjugation. / Includes bibliography. / Dissertation (Ph.D.)--Florida Atlantic University, 2014. / FAU Electronic Theses and Dissertations Collection

Organometallic chemistry is a powerful tool for the coupling of simple unsaturated molecules to form complex organic structures. Isonitriles (RNCs) are an attractive alternative to isoelectronic CO as C₁ sources in the pursuit of C,C coupling reactions. The electronic properties of the substituent on nitrogen in RNCs can bring about insertion chemistry that is different from the insertion reactions of CO. The insertion chemistry of RNCs with Group 4 (Ti, Zr, and Hf) butadiene complexes will be described. Cp*(Cl)Ti(2,3-dimethylbutadiene) (2.1) reacts with two equivalents of RNC to give η¹,η²-diimine complexes 2.2 (R = ^tBu) and 2.3 (R = 1-adamantyl). Cp*(Cl)Ti (N,N-di-^tBu-η¹,η²-diimine) (2.2), in the presence of pyridine, fragments to Cp*(Cl)Ti(NtBu)(NC₅H₅) (2.10) and an α-methylene cyclopent-3-enimine 2.11. The hafnium analog of 2.1, Cp*(Cl)Hf(2,3-dimethylbutadiene) (2.14), has been reported to give a cyclic amidine complex when treated with two equivalents of 2,6-dimethylphenyl isonitrile. By X-ray crystallography, however, this work finds that 2.14 and 2,6-dimethylphenyl isonitrile give instead a 2,5-diazahafnacyclopentane that features a σ-interaction between the C¬–C bond of a cyclopropane ring and the Hf. Cp*₂Zr(2,3-dimethylbutadiene) (3.1) reacts with tert-alkyl isonitriles to give η²-iminoacyl complexes Cp*₂⏞(⏟(Zr[CH₂ C(CH₃)C(CH₃)CH₂C)(NR)] 3.2 (R = tBu) and 3.3 (R = 1-adamantyl). Treatment of 3.2 with excess isopropyl isonitrile gives the η¹,η²-bis(iminoacyl) complex Cp*₂⏞(⏟(Zr[C(N^i Pr)CH₂ C(CH₃)C(CH₃)CH₂C)(N)iPr)] (3.4) and free tert-butyl isonitrile. The reaction of 3.1 with 2 equivalents of isopropyl isonitrile also affords 3.4, through the intermediate Cp*₂⏞(⏟(Zr[CH₂ C(CH₃)C(CH₃)CH₂C)(N^iPr)] (3.5). Carbonylation of 3.2 affords the Zr formimidoyl cyclopentadienolate 3.6. Treatment of a Zr hydride cyclopentadienolate (3.7), obtained from the carbonylation of 3.1, with tert-butyl isonitrile also affords 3.6. Isotopic labeling shows that the insertion of tert-butyl isonitrile into 3.1 and 3.7 is reversible.

This Thesis describes the synthesis and characterisation of new alkaline earth metal and aluminium gallyl complexes. Experimental studies were performed to investigate their structure. The reactivity of these species was also studied. <b>Chapter 1</b> introduces metal-metal bonded complexes containing alkaline earth metals and aluminium and the use of gallium(I) analogues of N-heterocyclic carbenes in the synthesis of heterobimetallic complexes of gallium. <b>Chapter 2</b> describes the synthesis and reactivity of alkaline earth gallyl complexes supported by beta-diketiminate ligands. <b>Chapter 3</b> presents the synthesis and reactivity of alkaline earth gallyl complexes supported by the carbazolide ligand CzOx. <b>Chapter 4</b> describes synthesis of aluminium-gallium bonded complexes supported by amidinate and b-diketiminate ligands and the attempted study of their reactivity. <b>Chapter 5</b> presents full experimental procedures and characterising data for the new complexes reported.

This Thesis describes the activity and mechanism of alkaline earth organohydroborate, tetrahydroborate and alkoxide catalysts for the ring-opening polymerisation (ROP) of cyclic esters including rac-, L-, D- and meso-lactide (LA), and rac-β-butyrolactone (rac-BBL). <b>Chapter One</b> introduces cyclic esters and general mechanisms for their ROP to give polyesters. Living and immortal ROP, an overview of stereocontrolled ROP, and determination of polylactide (PLA) stereosequences are given. Various techniques for polymer characterisations are also described. <b>Chapter Two</b> describes the activity and mechanism of heavy alkaline earth organohydroborate complexes for the ROP of LA. The synthesis and characterisation of alkaline earth alkoxide complexes serving as model species are also described, together with their activities for the ROP of LA. <b>Chapter Three</b> describes the activity and mechanism of a cyclic organohydroborate calcium complex for the ROP of LA. The role of borinic esters as chain transfer agents in the ROP of rac-LA is also discussed. <b>Chapter Four</b> describes the activity and mechanism of heavy alkaline earth tetrahydroborate complexes for the ROP of LA. The immortal ROP of rac-LA using heavy alkaline earth alkoxide complexes and borate esters as chain transfer agents is discussed. <b>Chapter Five</b> describes the activity and mechanism of alkaline earth organohydroborate, tetrahydroborate and alkoxide complexes for the ROP of rac-BBL. <b>Chapter Six</b> presents experimental procedures and characterising data for new complexes reported.

Dans le cadre de ma thèse, nous avons développé des édifices moléculaires associant des hélicènes et des carbènes N-hétérocycliques (NHC) afin de développer les premiers complexes métalliques de NHC-hélicènes. Dans un premier temps, des premiers complexes cycloiridiés de ligands NHC-[4,6]hélicènes, de formule générale IrLCp*X, dans lesquels le ligand porte un hélicène et un NHC greffés par l’intermédiaire d’un pont méthylénique, ont été obtenus. Les propriétés chiroptiques de ces complexes ont été étudiées à la fois expérimentalement et théoriquement. Nous avons ainsi pu démontrer la bonne communication entre les deux unités hélicène et NHC par l’intermédiaire de l’iridacycle, et la contribution du NHC dans les propriétés chiroptiques. Dans un deuxième temps, des complexes monocoordinnés de formule IrL(COD)X, à base d'iridium(I) et de ligands dans lesquels l’hélicène et le NHC sont orthofusionnés, ont été développés. L’efficacité de ces complexes en catalyse énantiosélective a été évaluée dans une réaction de transfert d’hydrogène de l'acétophénone, révélant un excès énantiomérique (ee) assez modeste allant jusqu’à 36%. D'autre part, des complexes d'iridium(III) cyclométallés de formule IrL(dfppy)2 ont révélé des propriétés de phosphorescence dans le vert et des temps de vie très longs. La comparaison du spectre d’émission avec celui d’un complexe analogue sans unité hélicénique a permis de mettre en évidence l’implication à la fois des orbitales d du métal mais aussi de l’unité NHC-hélicénique. Enfin, d'autres voies d’obtention d’hélicène-NHC ont été explorées, parmi lesquelles la synthèse d'un [4]hélicène-benzimidazole à partir d'un hélicène-boronate, suivie de sa déprotonation in situ et de sa cycloiridation. / During my PhD work, I have developed new molecular architectures combining helicenes and N-heterocyclic carbenes (NHC). Firstly, a novel family of cycloiridiated complexes bearing NHC-[4,6]helicene ligands, of general formula IrLCp*X, in which the ligand bear a helicene and a NHC grafted through a methylene bridge, were obtained. The chiroptical properties of these complexes have been analyzed both experimentally and theoretically. In this way, we have demonstrated the good communication between the helicene and NHC units through the iridacycle, and the contribution of the NHC in the chiroptical properties. Secondly, monocoordinated iridium(I) complexes of general formula IrL(COD)X, in which the ligands are this time constituted of orthofused NHC-helicenes, were obtained. The efficiency of these complexes in enantioselective catalysis was evaluated in a hydrogen transfer reaction on acetophenone, and revealed rather modest enantiomeric excess (ee) up to 36%. Then, cyclometallated iridium(III) complexes of general formula IrL(dfppy)2 were prepared and have shown to be phosphorescent in the green region with very long lifetimes. The comparison of the emission properties with an analogous complex without helicenic unit enabled to highlight the contribution of both the d orbitals of the iridium metal and the helicoïdal-NHC unit. Finally, other methods for the development of new NHC-helicenes structures have been explored. Among them, the synthesis of a [4]helicene-benzimidazole by transformation of a helicene-boronate, and the subsequent in situ deprotonation and cycloiridation, have been performed.

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Abstract not available

This thesis describes the investigation of the coordination and supramolecular chemistry of three different types of pyridine-containing ligand with a selection of Ag(I), Cu(I), Cu(II) and Cd(II) salts. The ligand types are flexible and four-armed, rigid and four-armed and bent with two rigid arms. All the ligands also display the ability to form additional supramolecular interactions. Chapter one introduces supramolecular chemistry and crystal engineering and covers background on several areas of current interest in these fields. Network structures, both coordination polymers and hydrogen-bonded systems, are discussed and topological analysis as a method of describing and comparing network structures is introduced. An outline of the ligand design, choice of transition metals and anions is given. Chapter two provides a review of flexible four-armed pyridine-containing ligands and their use in coordination chemistry. The synthesis and characterisation of three flexible four-armed ligands 1,2,4,5-tetrakis(2-pyridylmethyl-sulfanylmethyl)benzene (2tet), 1,2,4,5-tetrakis(3-pyridylmethyl-sulfanylmethyl)benzene (3tet) and 1,2,4,5-tetrakis(4-pyridylmethyl-sulfanylmethyl)benzene (4tet) are given. The synthesis and characterisation of the Ag(I), Cu(II) and Cd(II) complexes formed with these three ligands are also given. The complex of [Cd(2tet)(NO₃)₄] was structurally characterised by X-ray diffraction and was found to be a discrete species. The complexes {[Ag₂(3tet)](ClO₄)₂}n̲, {[Ag₂(3tet)](PF₆)₂}n̲, {[Ag₂(3tet)](CF₃CO₂)₂}n̲, {[Ag₂(4tet)]-(ClO₄)₂�2MeCN�2CHCl₃}n̲, {[Ag₂(4tet)](PF₆)₂�6MeCN}n̲ and {[Ag₂(4tet)](ClO₄)₂-�3H₂O}n̲ were likewise structurally characterised by X-ray diffraction. All these complexes were three-dimensional coordination polymers. A comparison of the seven structures is given at the end of the chapter. Chapter three reviews rigid four-armed pyridine-containing ligands and their use in coordination chemistry. The preparation of the rigid four-armed ligand 2,3,4,5-tetrakis(4-pyridyl)thiophene (pyth) is given. The synthesis and characterisation of the Ag(I), Cu(I) and Cd(II) complexes formed with this ligand are also given. The complexes [Ag(pyth)](BF₄)�3MeCN�CH₂Cl₂}n̲, [Ag(pyth)](PF₆)�MeCN�CH₂Cl₂}n̲, [Ag(pyth)]-(CF₃SO₃)�2MeCN�CH₂Cl₂}n̲, [Cu(pyth)](PF₆)�MeCN�CH₂Cl₂}n̲ and [(Cu₂I₂)(pyth)]-(BF₄)�1/2CH₂Cl₂�H₂O}n̲ were structurally characterised by X-ray diffraction. The complex with CuI was a two-dimensional coordination polymer, and the other four complexes were three-dimensional coordination polymers. A comparison of the five structures is given at the end of the chapter. Chapter four begins with a review of rigid angular bridging ligands and their use in coordination and supramolecular chemistry. The preparation of the ligand bis(4-pyridyl)amine (bpa) is given. The structural arrangement of bpa in the solid state was determined by X-ray diffraction. Complexes of Ag(I), Cu(I), Cu(II) and Cd(II) formed with this ligand were synthesised and characterised. The complexes {[Ag(bpa)(MeCN)](CF₃SO₃)}n̲, {[Ag(bpa)](PF₆)�MeCN}n̲, {[Ag(bpa)](ClO₄)-�2MeCN}n̲, {[Ag(bpa)](ClO₄)}n̲, {[Ag(bpa)](NO₃)}n̲, [(Cu₂I₂)(bpa)₂]n̲, {[Cu(bpa)₂Cl₂]-�3DMF�3/2H₂O}n̲, {[Cd(bpa)₂(NO₃)(H₂O)](NO₃)}n̲, {[Cd(bpa)₂(SO₄)(H₂O)]�3H₂O}n̲, [Cd(bpaH)₂(SO₄)₂(H₂O)₂]�2MeCN and {[Cd(bpa)(SCN)₂]�1/5iPrOH}n̲ were structurally characterised by X-ray diffraction. All complexes with Ag(I) were one-dimensional coordination polymers, with two of them helical, the other three zigzag. Both complexes with Cu(I) and (II) were two-dimensional coordination polymers. One complex with CdSO₄ was discrete, with the bpa ligands mono-protonated, but all other three other Cd(II) complexes were three-dimensional coordination polymers. Seven of these complexes showed hydrogen-bonding interactions linking them together to form supramolecular structures of higher dimensionalities. A comparison of the twelve structures is given at the end of the chapter. Chapter five is a brief summary of the outcomes of this thesis.