Thèses sur le sujet « Fura2 »

Furan and its derivatives are commonly found in numerous compounds such as natural products, polymers and medicines. The furan ring system is not only the core component to many natural products, but also serves as a key synthetic intermediate to access other more complex molecules. Among furan derivatives, furan fatty acids (F-acids) are an important class of natural products which are widely distributed in nature, and occupy a unique place in the field of medicinal chemistry because of their potent biological and pharmacological activity. This thesis examines the development of novel approaches towards highly substituted furans, with the ultimate goal of applying novel and high efficiency methods to the synthesis of F-acids and their derivatives. The first total synthesis of a natural product, an F-acids metabolite originally isolated from shark (Lamna ditropis) bile, was accomplished by the utilisation of an iodocyclisation of the corresponding 3-alkyne-1,2-diol to construct the furan nucleus; the synthetic route will be discussed in this thesis. Through the study of palladium-catalysis of a formal cyclisation to construct the furan ring system, a general route to access different F-acids has been developed. Splitting the F-acids into relatively simple fragments allows for easy preparation and modification of two fragments to produce a range of F-acids. The synthetic route was then applied to the formal synthesis of a natural product, F-acid F6. After optimisation of the synthetic route, total synthesis of F-acids F4, F6 and their analogues was accomplished.

The intramolecular Diels-Alder reaction of furan (IMDAF) provides a high degree of structural complexity in one step. However, reaction reversibility issues and the lower reactivity of furan in comparison to non-aromatic dienes prevent more widespread use of furan as a diene component in such reactions. Initial efforts to develop a new mode of organocatalysis which we hoped would facilitate IMDAF reaction was unfortunately unsuccessful, thus alternative means of IMDAF facilitation were investigated. For the first time, a comprehensive synthetic and computational study of the effect of halogen substitution on the IMDAF reaction has been undertaken. We have successfully demonstrated that halogenation of the furan moiety facilitates the IMDAF reaction (displaying increased reactivity to the non-halogenated analogue, regardless of halogen position), whereas dienophile halogenation hinders it. Additionally, careful selection of the position of the halogen on the furan can somewhat overcome the detrimental effect of having a halogen on the dienophile leading to highly functionalised cycloadducts with potential for further modification. Computational data produced by Martin Paterson and Justyna McKinlay support the idea that frontier molecular orbital effects cannot explain the experimental observations and we thus believe that the reactions are controlled by the interplay of three factors: positive charge stabilisation in the transition state and product, steric effects and a dipolar interaction term identified by the high level calculations. Finally, we have briefly demonstrated that nitro groups on the furan moiety also facilitate the IMDAF reaction whereas acyl groups appear to hinder the reaction. STEREOCHEMICAL ABSTRACT Any chiral compounds included in this thesis are racemic in nature. However, for clarity, such mixtures are schematically represented by drawings of only one of the enantiomers.

Die elektrochemische Copolymerisation von Furan und Thiophen oder 3-Chlorothiophen wurde erfolgreich realisiert in einer Elektrolytlösung von Bortrifluorid-Diethylether + Ethylether (Verhältnis 1:2) bei konstantem Elektrodenpotenzial. Die Zugabe von Trifluoroessigsäure (TFA) (10 Vol-%) zu Bortrifluorid-Diethylether + Ethylether (Verhältnis 1:2) erniedrigte das Oxidationspotenzial der Monomere; die Polymerisationsgeschwindigkeit erhöhte sich, da TFA die Ionenleitfähigkeit des Elektrolyts vergrößert. Die Homopolymere zeigen nur einen Redoxpeak, verursacht durch Polymeroxidation und - reduktion. Die elektrochemische Copolymerisation wird bei verschiedenen Potenzialen und mit unterschiedlichen Thiophen- oder 3-Chlorothiophenkonzentrationen untersucht. Die Copolymere zeigen ein Redoxpeakpaar, dessen Position sich wesentlich von der der Homopolymere unterscheidet. Mit zunehmendem Polymerisationspotenzial und/oder zunehmender Konzentration an Thiophen- oder 3-Chlorothiophen werden auch mehr Thiophen- oder 3-Chlorothiopheneinheiten in den Copolymerfilm eingebaut. Ein Elektropolymerisationmechanismus wird für die Copolymere vermutet und die Copolymere weisen eine recht gute Langzeitstabilität der Redoxaktivität nach Zyklen in Acetonitril auf. In situ UV-Vis-Spektren der Homo- und Copolymerfilme wurden gemessen und λ1max, welches dem π → π*- Übergang entspricht, wurde bestimmt. Der optische Übergang bei λ2max vom Valenzband in das höhere Bipolaronband wurde ebenfalls bestimmt. Die Bandlücke für die Homo- und Copolymerfilme beim direkten Übergang wurde von der Kante im Absorptionsspektrum abgeschätzt. Die elektrochemische Thermodynamik für die Homo- und Copolymerfilme deutet darauf hin, dass jeweils ein Elektron von den Polymersegmenten, bestehend aus 4 Monomereinheiten, entfernt wird. Die untersuchten leitfähigen Filme zeigen einen Leitfähigkeitssprung mit einer stabilen Leitfähigkeit bis EAg/AgCl= 2 V. Diese Leitfähigkeitsänderung ist reversibel. Polyfuran hat verglichen mit Polythiophen eine geringere Leitfähigkeit und die Leitfähigkeit von Poly(3-chlorothiophen) ist rund eine Zehnerpotenz niedriger als die von Polythiophen. Da das in situ Leitfähigkeitsverhalten der Copolymere nicht die Summe der einzelnen Homopolymere bildet, kann man ausschließen, dass es sich bei den abgeschiedenen Copolymeren um Blockcopolymere handelt. Mit Hilfe der FTIR-Spektroskopie wurden Schwingungsspektren der Homo- und Copolymerfilme aufgenommen. Die Ergebnisse zeigen, dass es zur α-α'-Verknüpfung zwischen den Radikalkationen während der Copolymerisation kommt, was charakteristisch ist für α-substituierte fünfgliedrige heterozyklische Verbindungen. Der Mechanismus der elektrochemischen Degradation von Furan-Thiophen-Copolymeren wird ebenfalls mit Hilfe der gemessenen Spektren beschrieben. Die in situ Resonanz-Raman-Spektroskopie ergab, dass die spektroskopischen Eigenschaften der Copolymere zwischen denen der Homopolymere lagen. Bei höheren Polymerisationspotenzialen und höheren Konzentrationen an Thiophen oder 3-Chlorothiophen werden mehr Thiophen- oder 3- Chlorothiopheneinheiten in die Copolymerketten eingebaut. Es ist offensichtlich, dass die Ramanspektren der Copolymere wesentlich komplexer sind als die der Homopolymere, wodurch die Auswertung erschwert wird. Dennoch erinnern die Ramanspektren der Copolymere an die der Homopolymere. Die spektroelektrochemischen Eigenschaften der Copolymere haben bestätigt, dass deren Charakteristika zwischen denen der Homopolymere liegen, was deutlich macht, dass die Oxidation von Monomeren möglich ist und dass die Copolymerketten demnach aus Furan- und Thiophen- bzw. 3- Chlorothiopheneinheiten bestehen können
Electrochemical copolymerization of furan and thiophene or 3-chlorothiophene was successfully realized in a solvent system consisting of boron trifluoride ethyl ether (BFEE) + ethyl ether (EE) (ratio 1:2) at constant electrode potential. The addition of trifluoroacetic acid (TFA) (10 % by volume) to BFEE + EE (ratio 1:2) decreased the oxidation potential of the monomers; the polymerization rate was also accelerated because TFA increases the ionic conductivity of the electrolyte. The homopolymers have only one redox peak caused by polymer oxidation and reduction. Electrochemical copolymerization both at different potentials and with different thiophene or 3-chlorothiophene concentrations is investigated. The copolymers show one anodic/cathodic peak couple that appears at a position quite different from the positions observed with homopolymers. More thiophene or 3-chlorothiophene units are incorporated into the copolymer film with an increasing polymerization potential of the copolymer and/or with an increasing concentration of thiophene or 3- chlorothiophene in the feed. An electropolymerization mechanism of copolymers has been proposed, and the copolymers show a fairly good long-term stability of the redox activity after cycling in acetonitrile. In situ UV-Vis spectra of the homo- and copolymer films were measured and λ1max which corresponds to the π → π* transition is determined. The optical transition with λ2max from the valence band into the higher bipolaron band is also assigned. The band gap (Eg) for homo- and copolymer films from a direct interband transition is estimated from the absorption edge of the spectrum. The redox thermodynamics of the homo- and copolymer films suggest that one electron is removed from polymer segments containing four monomer units. The studied conducting films show a single conductivity change with a stable conductivity up to EAg/AgCl= 2 V. The conductivity of these films is almost restored when the potential shift direction is reversed. Polyfuran compared to polythiophene, has a lower conductivity and the conductivity of poly(3-chlorothiophene) is around one order of magnitude lower than that of polythiophene. The in situ conductivity properties of the copolymers are not the sum of those of the individual homopolymers. This result may eliminate the possibility that the copolymers can be considered as block copolymers. Vibrational spectra of homo- and copolymer films investigated in this study have been obtained using FTIR spectroscopy. The results indicate that α-α' coupling of radical cations has taken place in the copolymerization. This is a characteristic of α-substituted five-membered heterocyclic compounds. The electrochemical degradation mechanism of furan-thiophene copolymers is also described using the obtained spectra. The in situ resonance Raman spectroscopy of the copolymers shows spectroscopic properties intermediate between those of homopolymers. At higher polymerization potentials and at higher concentrations of thiophene or 3-chlorothiophene in the feed more thiophene or 3-chlorothiophene units are incorporated into the copolymer chains. It is obvious that the Raman spectra of the copolymers are more complex than those of homopolymers, which makes the assignment difficult. However, the in situ Raman spectra of the copolymers are reminiscent of those of the homopolymers. The spectroelectrochemical properties of the copolymers confirmed that the copolymers show intermediate characteristics between the homopolymers, implying that oxidation of monomers is possible and the copolymer chains may accordingly be composed of furan and thiophene or 3-chlorothiophene units

This thesis describes the use of both silver nitrate, and iodine, to promote 5-endo-dig cyclisations for the formation of furans. The synthesis of kahweofuran and other furan-containing fragrance compounds is described, along with an investigation into the selectivity of the 5-endo-dig cyclisation process. Chapter 2 describes the synthesis of furan-containing analogues of known fragrance compounds using a silver-catalysed cyclisation methodology. The analysis of some of these compounds by an "expert nose" is discussed. Chapter 3 describes the synthesis of kahweofuran, a furan-containing compound reported to be one of the major odour constituents of roasted coffee. Chapter 4 describes an investigation into the cyclisation of triols upon exposure to silver nitrate or iodine when more than one cyclisation pathway is possible.

The starting material for this project was the highly functionalized compound 3,3,4,4- tetraethoxybut-1-yne (TEB) and it can be prepared from ethyl vinyl ether by a 4-steps synthesis. The third and the fourth step in TEB synthesis were sensitive to reaction conditions, so it was developed a strategy to try to optimize the third step and obtain TEB with higher yields. An approach, which tries to optimize also the fourth step, will be developed in further works. Several γ-hydroxy-α,β-unsaturated acetylenic ketones can be prepared from 3,3,4,4- tetraethoxybut-1-yne. TEB and γ-hydroxy-α,β-unsaturated acetylenic ketones have been previously synthesized in good yields using various reaction routes. In this work will be shown the synthesis of 1,1-diethoxy-5-hydroxyhex-3-yn-2-one, 1,1-diethoxy-5-hydroxyundec-3-yn-2-one and 1,1-diethoxy-5-hydroxydodec-3-yn-2-one, which will react with ethyl acetoacetate to give, respectively, ethyl 4-(3,3-diethoxy-2-oxopropyl)-2,5-dimethylfuran-3-carboxylate, ethyl 4-(3,3-diethoxy-2-oxopropyl)-5-hexyl-2-methylfuran-3-carboxylate and ethyl 4-(3,3-diethoxy-2-oxopropyl)- 5-heptyl-2-methylfuran-3-carboxylate furan derivatives. This thesis project was carried out during the year 2011, at the Department of Chemistry of the University of Bergen.

Furopyranones and furopyrrolones are furan-fused bicyclic heterocycles containing pyranone and pyrrolone framework respectively. Many natural products and pharmaceutical agents include these core structures. In this study, new synthetic methodologies were developed for the synthesis of furopyranone and furopyrrolone derivatives. In the first section of this thesis, methyl 2-(2-methoxy-2-oxoethyl)-3-furoate was hydrolyzed forming 2-(carboxymethyl)-3-furoic acid which underwent intramolecular cyclization reaction using two different methodologies forming furopyranone derivatives. In the second part of the study, 2-(carboxymethyl)-3-furoic acid was regioselectively converted to acyl azide, which was accomplished by utilizing the reactivity differences between the two acid functionalities within the molecule. This acyl azide was then transformed into urea derivative to perform cyclization reaction yielding a new furan-fused heterocycle, furopyrrolone. In both parts of this study, ring closure reactions were achieved benefiting from the reactivities of different carbonyl groups within the molecules.

Thesis presented in partial fulfillment of the requirements for the degree of Master of Technology (MTech) at Department of Chemistry, Faculty of Applied Science, Cape Peninsula University of Technology 2011
Aromatic polyamides (PAs) are widely used as high-performance polymers in technical applications due to their unique combination of outstanding thermal, optical, mechanical and chemical properties. Although PAs are mostly utilized where strength or heat resistance is of primary concern, they also find use in other important applications such as in NOMEX membranes for desalination of brackish water or seawater. PAs do however have some disadvantages such as high melting points, high glass transition temperatures (T 9) and a limited solubility in most organic solvents, wh.ich makes their processing difficult. Polyureas (PUs) are generally known for their excellent thermal stability and high chemical resistance due to the presence of thermally stable bonds of aromatic or heterocyclic ring systems along their backbone. Both polymer systems are poorly researched when it comes*' the introduction of furan units into the chains. The same is valid for cases where two or more different diacids or diamines are incorporated. The aim of this study was therefore to investigate the influence of furan units in the polymer chains and the change in properties if the composition of starting materials is varied further. Nineteen PAs were prepared via the interfacial polymerization method and the homogeneous phase polymerization method. These polymers were prepared either with furan- or isophthalic acids in their chains and then compared with the copolymers, containing both diacids in different ratios. Products were characterized by various analytical techniques. Furanoyl-2,5-dichloride (FDC) and different amounts of isophthaloyl chloride (IPDC) - 0, 10, 30 and 50% - as the basic starting monomers were reacted individually with four diamines: m-phenylen diamine (MPD), 4,4'-diamino diphenylsulfone (DDS), 4,4'-diamino diphenylether (ODE) and 2,4-bis(4-aminophenyl)-6-phenyl-1,3,5-triazine-2,4,6-triamine (BAT) by interfacial or homogeneous polycondensation reactions. Two polyureas, starting with furanoyl-2,5-diazide (FDZ) and transformed into the diisocyanate were prepared by reaction with two diamines, namely MPD and DDS in homogeneous solution. The PAs and PUs were characterized by Fourier-Transform Infrared Spectroscopy (FTIR), Proton NMR CH), Carbon NMR C3C), Gel Permeation Chromatography (GPC), Thermogravimetric Analysis (TGA) and Differential Scanning Calorimetry (DSC). The water up-take per polymer unit (mol water I repeat unit of the polymer) was measured. The values for 70% Relative Humidity (RH) were between 0.87 and 1 ~80 moles of water per repeat unit and for 43% RH between 0.40 and 1.35 mols.

This thesis describes the use of silver nitrate and iodine to promote 5-endo-dig cyclisations in the synthesis of furans. The oxidation of furylethanols will be discussed as will methods to synthesise furylacetic acids. The total synthesis of a natural product, Plakorsin B will be described along with the total synthesis of the furan fatty acids F5 and F6 as well as giving an overview of their proposed role in Nature. Finally, a new methodology for methylation of halogenated heterocycles will be discussed.

Acredita-se que sinais elétricos endógenos afetem remodelamento, metabolismo, reparo e crescimento ósseos. Existe uma ampla literatura que trata do efeito de sinais elétricos externos sobre as respostas de síntese, mitogênese e proliferação em osteoblastos e células ósseas in vitro. Acredita-se que as respostas fisiológicas ao estimulo elétrico sejam devidas a mecanismos celulares que envolvem variações na concentração citosólica de cálcio. No presente estudo esse efeito celular foi observado através da estimulação direta, por campo elétrico de intensidade fisiologicamente significativa de 10mV/cm e frequência 1,5 MHz, de células ósseas em cultura primária obtidas a partir da calota calvária de ratos da raça Sprague-Dawley. Os mecanismos de transdução do campo elétrico são investigados pela mensuração em tempo real do efeito do campo elétrico na concentração citosólica de Ca2+ utilizando-se técnica de fluorescência de Fura-2, em um sistema que permite a medida em células individuais. As estimulações elétricas resultaram em variações significativas na concentração de cálcio citosólico. Mais especificamente, observou-se um aumento na amplitude e na duração das oscilações de cálcio iônico, com tempos de latência variáveis para as células estudadas.
Endogenous electrical signals have been thought to affect bone remodeling, metabolism, healing and growth. Much literature exists concerning the effect of external electrical signals on synthetic, mitogenic, and proliferative responses of osteoblasts or osteoblast-like cells in vitro. Physiological responses to electrical stimulation are thought to be due to cellular mechanisms involving cytosolic calcium concentration changes. In this study this cellular effect was observed by directly stimulating primary culture bone cells from Sprague-Dawley rat calvaria at physiological significant field strength of 10 mV/cm and frequency 1,5 MHz. Electric field transduction mechanisms are investigated by measuring the real-time electric field effect on cytosolic Ca+2 concentrations using Fura-2 fluorescence technology in a system capable of measurement on a cell-by-cell basis. The electrical stimulations resulted in significant changes in cytosolic calcium concentration. More specifically, an increase was noted in calcium oscillation amplitude and duration, and a variable response latency period for the cells studied.

Tetrahydrobenzofurans and tetrahydroindoles are two very valuable classes of substances which have wide usage area
either as starting materials for drug substances or many other compounds which have fused heterocyclic rings in their structures and pharmacophore for many complex natural products
syntheses of derivatives of these compounds with different substitution patterns, is an exciting challenge for many scientists. Benzofuran and tetrahydroindole derivatives, which are potent bioactive substances, are synthesized from various cyclohexanone derivatives that are allylated by Stork-enamine or Mn(OAc)3 mediated allylation methods. Allylated ketones are later transformed to benzofuran derivatives upon treatment with base or tetrahydroindole derivatives upon treatment with primary amines.

Polymeric materials are strongly entrenched in our society, where PVC is one of the most versatile one. The replacement of traditional phthalates plasticizers, used in the production of soft PVC, has been object of intense research in the last decades, due to their toxicological effects on humans and environmental and the increasing awareness regarding the use of fossil fuels. Bio-based platform chemicals, 5-hydroxymethylfuran (HMF) and 2,5-furandicarboxylic acid (FDCA), accessible from lignocellulosic biomass, have been used in this research as starting materials for the production of alternative furan-based plasticizers. By reduction reaction of HMF, 2,5-bishydroxymethylfuran (BHMF) was obtained and involved in a esterification reaction, which led successfully to the first desired furan-based plasticizer. An esterification acid-catalyzed by Amberlyst-15 on tetrahydrofuran- 2,5-dicarboxylic acid (THFDCA), obtained from FDCA by hydrogenation reaction, gave access to the second promising plasticizer. First investigations of BHMF and 2,5-bis(hydroxymethyl)tetrahydrofuran (BHMTHF) etherification reactions were carried out, in order to obtain further substrates that could be used as potential plasticizers.

Diels-Alder reactions, inter- and intramolecular, are of paramount importance in synthetic organic chemistry. Few reactions can compete with the Diels-Alder cycloaddition with respect to the degree of structural complexity that can be achieved in a single synthetic step. The high regio- and stereoselectivity typically displayed by this pericyclic process and the ease of execution have contributed toward its popularity. In the present report, we describe work towards and the study of heteronuclear intramolecular Diels-Alder re~ctions involving substrates containing a furan ring (the diene) tethered to a diazene moiety (the dienophile). A model study on the synthesis of chiral racemic intramolecular Diels-Alder substrates is presented, followed by work towards chiral non-racemic substrates. The tricyclic Diels-Alder adducts obtained herein are potential precursors to a wide variety of novel, functionalised spiro-amide systems, which are anticipated to find use as building blocks in the synthesis of natural products, or their synthetic bioactive structural analogues.

This thesis aims to explore questions of artistic interdisciplinarity through a study of the Catalan theatre company La Fura dels Baus's practice in the period from 1979 to 1989. This study sees artistic interdisciplinarity and La Fura as prominent aspects of contemporary theatre,which have received little critical attention in theatre studies. The general introduction attempts to define a conceptual and contextual framework for this thesis. Chapter 1 examines `artistic interdisciplinarity' as a significant conceptual instrument for this study. Chapter 2 investigates some instances of artistically interdisciplinary practice before and after performance art. Chapter 3 takes a general look at what constitutes the wider social and aesthetic context within which La Fura had its inception. Chapter 4 focuses on the group's early productions in Catalonia from 1979 to 1983, a period often neglected by scholars writing on the company's work. Chapter 5 presents Accions (1983-87),S u o/Suz (1985-91) and TierMon (1988- 90). These three productions comprise the features of the lenguajefurero. Chapter 6,7 and 8 examine these features, La Fura's manipulation of scenic threads such as space, time, sound, image, body and movement as well as the interdisciplinary exchanges with different arts. Chapter 8 also looks at the relations among La Fura's productions and questions of national and aesthetic identities in Catalonia and Spain. The final unit presents the conclusions of this thesis. Through a cross-disciplinary methodology, this thesis has the double ambition of stimulating further debates and actions in re-mapping theatrical language as well as connecting ideas about both main objects of study to an understanding of the art of theatre and its environments at the end of the twentieth century.

Doutoramento em Química
A futura e inevitável escassez dos recursos fósseis, juntamente com o aumento imprevisível dos seus preços, levou, nas últimas décadas, a um aumento impressionante de iniciativas dedicadas não só à procura de fontes alternativas de fornecedores de energia, mas também de produtos químicos e polímeros a partir de fontes renováveis, em particular da biomassa vegetal. Entre estes, os polímeros derivados de monómeros furânicos constituem uma classe única de materiais cujas estruturas podem, em princípio, simular virtualmente os seus homólogos actualmente derivados de recursos fósseis. O anel furânico é uma estrutura heterocíclica com um carácter diénico pronunciado, o que torna-o um dieno particularmente apropriado para a reacção de Diels-Alder (DA) com dienófilos como a maleimida. Um dos aspectos mais relevantes da reacção de DA é a sua reversibilidade em função da temperatura, a qual permite que os aductos sejam facilmente revertidos nos seus precursores por aumento da temperatura (reacção de retro-DA). No caso específico da combinação furano-maleimida, a formação do aducto predomina até cerca de 60ºC, enquanto a reacção inversa é dominante acima de 100ºC. A combinação desta característica da reacção de DA com a química de compostos furânicos pode abrir um novo caminho para a preparação de materiais macromoleculares funcionais com base em fontes renováveis e com aplicações promissoras como auto-reparação e reciclabilidade. O principal objectivo desta Tese, é a síntese e caracterização de novos materiais poliméricos termo-reversíveis, aplicando a reacção de DA a monómeros complementares com estruturas dos tipos furânico (o dieno, designado por A) e de maleimida (o dienófilo, designado por B). A primeira etapa neste trabalho envolveu a síntese, purificação e caracterização de novos monómeros furânicos e de maleimida do tipo AA, A3, BB, B3, AB, AB2, cada um com diferentes grupos separadores das funções reactivas. Posteriormente, estes monómeros foram polimerizados e despolimerizados por ciclos de DA/retro-DA utilizando diferentes combinações. A formação e dissociação de todos os aductos de DA foram seguidas por ambas espectroscopias de UV e RMN de 1H. O primeiro sistema de DA estudado foi uma combinação modelo entre reagentes mono-funcionais (-A+-B), nomeadamente o acetato furfurílico (FA) e a N-metilmaleimida (MM), ambos comercialmente disponíveis. O objectivo desta abordagem foi estudar a cinética e o equilíbrio da formação/dissociação dos aductos de DA e obter indicações sobre as condições mais adequadas a serem usadas na preparação dos correspondentes novos materiais macromoleculares. Além disso, pretendia-se verificar a presença ou ausência de reacções secundárias que poderiam intervir em ambas as vias directa e inversa das reacções, mesmo após vários ciclos. A espectroscopia de UV forneceu informação quantitativa sobre a cinética de formação do aducto através da diminuição progressiva da absorvência máxima a 293 nm correspondente ao grupo maleimida, a diferentes temperaturas (35, 50, 65 ºC) Reciprocamente, a correspondente reacção de retro-DA foi seguida a 90 ºC através do aumento do mesmo pico. A reversibilidade destes sistemas foi verificada com sucesso após uma sequência de ciclos de DA/retro-DA. Adicionalmente, verificou-se que os espectros originaram um ponto isosbéstico, provando que estes sistemas não envolvem quaisquer reacções secundárias. Uma vez que foi usado um excesso de FA, as reacções de DA modelo apresentaram um comportamento cinético de pseudo-primeira ordem, com a constante de velocidade k mais alta (2.1x10-5 dm3mol-1s-1) para T=65 ºC. A correspondente energia de activação foi de 39.0 kJ.mol-1. A reacção de retro-DA seguiu um comportamento de primeira ordem, com constante de velocidade de 1.6x10-6 s-1. A evolução deste sistema por RMN de 1H a 65ºC deu-nos informações mais detalhadas sobre a sua evolução estrutural, ou seja, à medida que a intensidade dos picos atribuídos à formação do aducto aumentaram progressivamente ao longo do tempo, os pertencentes aos reagentes iniciais diminuiram proporcionalmente. O “rendimento final”, calculado após 20 dias à temperatura ambiente, foi de aproximadamente 70%. A reacção de retro-DA foi depois seguida a 90ºC, observando-se tal como na espectroscopia de UV, o deslocamento da reacção no sentido da regeneração dos reagentes de partida. A viabilidade de múltiplos ciclos de DA/retro-DA estabelecidos pela espectroscopia de UV foi igualmente confirmada por RMN de 1H. O passo seguinte envolveu o estudo de um sistema de policondensação linear baseado no crescimento gradual por reacção de DA entre um monómero bisfurânico A-A e um do tipo bismaleimida B-B, seguindo a mesma abordagem que no sistema modelo. O poliaducto linear foi obtido a partir de soluções equimolares dos monómeros, por reacção de DA a 65ºC. O progresso desta polimerização foi seguido por espectroscopia de UV e RMN de 1H e, mais qualitativamente, pelo aumento da viscosidade do meio. A reacção seguiu um comportamento de segunda ordem, com uma constante de velocidade de 9.4x10-6 dm3mol-1s-1, e observou-se novamente um ponto isosbéstico nos dados de UV. Os espectros de RMN apresentaram o padrão esperado, nomeadamente o aumento progressivo dos sinais associados ao aducto e a correspondente diminuição dos grupos furano e maleimida livres. A despolimerização do poliaducto através da reacção de retro-DA foi seguida a 110ºC usando as mesmas técnicas. Os dados de UV mostraram o retorno progressivo da absorção dos grupos de maleimida, seguindo um comportamento cinético de primeira ordem, com constante de velocidade de 2.5x10-6 s-1, até à completa regeneração de ambos os monómeros. Os espectros de RMN providenciaram mais uma vez informação estrutural sobre o progresso da despolimerização, a qual foi acompanhada por uma diminuição progressiva da viscosidade. Adicionalmente, para seguir a retro- DA, adicionou-se um excesso de composto furânico monofuncional, nomeadamente o 2,5-dimetilfurano (DMFu), ao sistema de modo a bloquear as funções maleimida complementares, evitando assim a repolimerização após arrefecimento. Os productos isolados foram então o monómero bisfurânico AA, DMFu que não reagiu e o bisaducto não-polimerizável de BB com DMFu. Este resultado indicou claramente que o polímero foi de facto revertido nos seus monómeros durante a reacção de retro-DA. O terceiro sistema estudado foi outra polimerização linear, seguindo as mesmas condições experimentais que os anteriores, mas com uma estratégia diferente de modo a contornar o problema clássico de assegurar a estequiometria exacta dos monómeros. As estruturas dos monómeros utilizados incorporam ambos os grupos reactivos, i.e, moléculas do tipo A-B. A polimerização prematura destes monómeros intrinsecamente reactivos foi evitada com a protecção do grupo maleimida na forma de um aducto de DA com furano, até a incorporação do substituinte furânico na outra extremidade. Portanto, a policondensação destes monómeros foi iniciada após a desprotecção in situ deste composto mediante aquecimento, seguido de arrefecimento até à temperatura adequada para polimerizar. Os resultados obtidos por UV e RMN sugerem que de facto o uso de monómeros do tipo A-B oferece um melhor sistema linear. Em seguida, foram estudados sistemas de policondensação não-linear por reacção de DA, entre monómeros (um ou ambos) com funcionalidade superior a dois, nomeadamente sistemas do tipo A3+B-B ou A-A+B3, seguindo mais uma vez as mesmas condições experimentais. Uma vez que utilizam monómeros complementares contendo, em média, mais de duas funcionalidades, estes sistemas conduzem a materiais reticulados. Nestes estudos, foram usadas três razões molares de [maleimida]/[furano], nomeadamente 1.0, 0.75 e 0.5, de modo a estudar ambas as situações de não-gelificação e reticulação. Ambos sistemas apresentaram um comportamento regular e boa reciclabilidade quer para gerar situações que possam conduzir à formação de redes a diferentes graus de conversão, ou que possam parar antes da sua obtenção, conforme previsto pela equação de Flory-Stockmayer. Como esperado, a utilização de grupos complementares em quantidades estequiométricas produziu o espessamento mais rápido e a reticulação quase completa; à medida que a quantidade relativa de monómero trifuncional decresceu, as reacções pararam antes da reticulação, ou seja, originaram meios altamente viscosos contendo polímeros solúveis altamente ramificados. As reacções de retro-DA a 110 ºC conduziram à gradual dissolução das partículas de gel (quando presentes), tendo sido comprovado pelos espectros de UV e de RMN de 1H, evidenciado a regeneração dos monómeros. Tal como no sistema do tipo A-A+B-B, a reacção de retro-DA foi seguida adicionando um excesso de DMFu ao sistema reaccional. Como esperado, os produtos finais foram os monómeros furânicos, o DMFu em excesso e o trisaducto ou o bisaducto maleimida-DMFu, o que confirma a eficiência da despolimerização com regeneração dos monómeros iniciais. O último sistema de policondensação por reacção de DA envolveu um monómero assimetricamente substituído do tipo AB2, capaz de originar estruturas macromoleculares hiper-ramificadas que não reticulam. Este estudo preliminar deste sistema foi seguido nas mesmas condições experimentais que os anteriores, apresentando um comportamento com as características esperadas.
The inevitable future scarcity of fossil resources, together with their skyrocketting prices, has led in the last decades to a dramatic increase of initiatives devoted not only to the search for alternative sources of energy providers, but also to the search for chemical commodities and polymers from renewable resources, namely the vegetable biomass. Among these, polymers from furan monomers constitute a unique class of materials whose structures can in principle simulate virtually all their current fossil-derived counterparts. The furan heterocycle displays a pronounced dienic character, which makes it highly suitable as diene in the Diels-Alder (DA) reaction, with dienophiles like maleimide. One of the most relevant aspects of the DA reaction is its thermal reversibility, which allows the adducts to be readily reverted to their precursors as the temperature is raised (retro-DA reaction). In the specific case of the furan-maleimide combination, the adduct formation dominates up to ca. 60ºC, whereas the reverse reaction is overwhelming above ca. 100ºC. The coupling of this DA feature with the furan chemistry can open a new way to prepare functional macromolecular materials based on renewable resources with novel properties and promising applications like mendability and recyclability. In this Thesis, the main goal is the synthesis and characterisation of novel thermoreversible polymer materials by means of the DA reaction, using complementary monomers bearing furan (the diene, assigned as A) and maleimide (the dienophile, assigned as B) moieties. The first step in this study was the synthesis, purification and characterization of new furan and maleimide monomers, viz. AA, A3, BB, B3, AB, AB2, each bearing different spacing moieties separating the reactive functions. They were then polymerized and depolymerised using different modes of DA/retro-DA cycles. The formation and decoupling of all the DA adducts were followed by both UV and 1H NMR spectroscopy. The first DA system investigated was on a model combination of monofunctional reagents (-A+-B), namely the commercially available furfuryl acetate (FA) and N-methylmaleimide (MM). The purpose of this approach was to study the kinetics and the equilibrium of the formation/decoupling of the DA adducts and to provide clear indications about the most appropriate conditions to be applied in the preparation of the corresponding novel macromolecular materials. Additionally, it aimed at verifying that no detectable side reactions intervened in both forward and backward pathways, even after several cycles. The UV spectroscopy provided quantitative information on the kinetics of the DA adduct formation by monitoring the progressive decrease in the maximum absorbance at 293 nm related to the maleimide moiety, at different temperatures (35, 50, 65ºC). Conversely, the corresponding retro-DA reaction was followed at 90ºC through the increase of the same peak. The reversibility of these systems was successfully checked over a couple of cycles. Additionally, all set of spectra gave rise to an isosbestic point, which proved that these systems did not involve any side reactions.Since an excess of FA was used here, these model DA reactions displayed a pseudo-first order behaviour, with the highest rate constant k (2.1x10-5 M-1.s-1) for T= 65ºC. The corresponding activation energy was found to be 39.0 kJ.mol-1. The retro-DA reaction followed a first order behaviour, with a rate constant of 1.6x10-6s-1.The evolution of the same system followed by 1H NMR spectroscopy at 65ºC gave a detailed insight into its structural evolution, viz. as the intensity of the peaks assigned to the adduct formation progressively increased with time, those belonging to the initial reagents decreased correspondingly. The “final yield” taken after 20 days at room temperature, was approximately 70%. The retro- DA reaction was then carried out at 90ºC, and showed the same features as its UV counterparts, namely the displacement of the reaction towards the regeneration of the initial reagents. The feasibility of multiple DA/retro-DA cycles established by UV spectroscopy was confirmed here. The subsequent stage involved the study of a linear polycondensation system based on the stepwise DA growth between a difuran monomer A-A and a complementary bismaleimide B-B, following the same approach as the model system. The formation of the linear DA polyadduct was achieved by letting equimolar solutions evolve at 65 ºC. The progress of this polymerization was followed by UV and 1H NMR spectroscopy and, more qualitatively, by the increase in the viscosity of the medium. The reaction followed a second order behaviour, with a rate constant of 9.4x10-6 M-1.s-1, and again, a characteristic isosbestic point was observed in the UV data. The NMR spectra gave the expected pattern, namely the progressive increase in the signals associated with the adduct and the corresponding decrease of those attributed to the unreacted furan and maleimide cycles. The depolymerization of the polyadduct through the retro-DA reaction was followed at 110ºC by the same techniques. The UV time scans showed the progressive return of the absorption due to maleimide moieties following a first-order kinetic pattern, with a rate constant of 2.5x10-6 s-1, until both monomers were fully regenerated. The 1H NMR spectra provided once more structural information about the course of this depolymerization, which was accompanied by a progressive decrease in viscosity. Additionally to follow the retro-DA, an excess of a monofunctional furan compound, namely 2,5-dimethylfurfural (DMFu), was added to the system in order to block the complementary maleimide functions, thus avoiding the repolymerisation after cooling. The isolated products were then the difuran monomer AA, the unreacted DMFu and the non-polymerizable bisadduct of BB with DMFu. This result clearly indicated that the polymer had indeed reverted to its monomers during the retro-DA. The third system studied was another linear polymerization, following the same experimental conditions as the previous, but with a different strategy, in order to avoid the classical problem of ensuring the exact monomer stoichiometry. Here, the monomers incorporated both reactive moieties in their structures, i.e. A-B molecules. Here, the premature polymerization of these intrinsically reactive monomers was avoided by protecting the maleimide group in the form of a furan-DA adduct, until the incorporation of the furan moiety. Therefore, the polycondensation of these monomers was initiated after the in situ deprotection of this compound through heating, followed by the cooling to appropriate temperature for polymerization. The results obtained by both UV and NMR spectroscopy suggested that indeed the use of an A-B monomer provides a better linear system. Non-linear DA polycondensations between monomers (one or both) with functionality higher than two, viz. A-A+B3 or A3+B-B systems, were then studied, following once more the same experimental conditions. The use of complementary monomers bearing on average more than two functionalities lead to crosslinked materials. In these systems, three [maleimide]/[furan] molar ratios, viz. 1.0, 0.75 and 0.50, were applied in order to examine both nongelling and crosslinking situations. Both types of systems displayed a clean-cut behaviour and good recyclability to generate situations either leading to the formation of a network at different degrees of conversions, or ending before its attainment, as predicted by the Flory-Stockmayer equation. As expected, the use of complementary moiety stoichiometry produced the most rapid thickening and near-complete crosslinking, whereas as the relative amount of trifunctional monomer was decreased, the reactions stopped short of crosslinking, i.e. gave highly viscous media containing soluble highly branched polymers. The retro-DA reactions at 110ºC revealed the gradual dissolution of the gel particles (when present), while the UV and 1H NMR spectra gave, once more, the details of the depolymerization processes leading the systems steadily back to the monomers. As in A-A+B-B depolymerization, to follow the retro-DA, an excess of DMFu DA trap, was added to the systems under the same conditions. As expected, the final products were the furan monomers, the unreacted DMFu and the non-polymerizable trisadduct or the bisadduct of maleimide-DMFu, confirming the efficiency of the retro-DA depolymerisation in the regeneration of the starting monomers. The last DA polycondensation system involved an assymmetrically substituted monomer of the AB2 type, capable of generating hyperbranched macromolecular structures that do not crosslink. This preliminary study was followed by the experimental approach applied above and the behaviour of the system displayed the expected features.
POCTI; FCT; FSE - SFRH/BD/28271/2006

Oxidation of furan rings in the presence of hydroxy groups can lead to spirobutenolides. This methodology has been applied in synthetic studies towards three natural products: Pyrenolide 0 - An antileukaemic fungal metabolite. AL-(1) - An antitumor plant natural product. Sawaranospirolides - Four highly oxygenated spiroacetals isolated from the heartwood of the Sawara tree.

Personnage atypique de son milieu, F. Garnier nait en 1839 à St-Etienne dans une famille catholique et légitimiste. Rien ne le prédestine alors à devenir officier de marine républicain et voltairien, sinon un esprit farouchement indépendant et frondeur très tôt affirme. Diplômé de l'école navale en 1858, il est très vite arrache a sa famille avec laquelle il entretient des rapports passionnels. Enrôle dans les campagnes de chine et de Cochinchine, son avenir se joue dans ce 1er contact avec l’Asie. Toute son énergie tend alors à vouloir donner à la France sa place sur l'échiquier colonial et a en évincer l’Angleterre. Préfet de Cholon en 1864, appendice chinois de Saigon, il se distingue par de prodigieuses qualités d'intelligence, de travailleur, de décideur. Mais c'est surtout l'exploration du Mékong (1866-68) qui lui confère sa notoriété. Unanimement honore a son retour en France, il songe pourtant aussitôt a repartir en Asie. La guerre de 70 l'en empêche. Acteur du conflit, il tente vainement d'entrer en politique et s'insurge vivement contre la capitulation. Désormais mari et père, il s'installe à Shanghai à l'automne 1872 pour y mener à la fois des activités scientifiques et de commerce et entreprend plusieurs voyages en chine méridionale. En juillet 1873, un ordre de l'amiral-gouverneur le pousse imprudemment dans une aventure aussi soudaine que malheureuse. En acceptant de commander une expédition au Tonkin - en fait, une tentative de conquête camouflée- il signe son arrêt de mort, dévoré par ses ambitions. Un coup de folie le livre aux mains des pavillons noirs qui le décapitent le 21 xii 1873 après qu'il se soit emparé de la citadelle d'Hanoi, amorçant ainsi la conquête du Tonkin. Au cœur d'une polémique après sa mort, oublié des générations de l'après-Indochine française, il laisse cependant à la postérité quelques solides ouvrages théoriques sur le colonialisme et de passionnants récits de voyages

L'épuisement des réserves de combustibles fossiles et l'augmentation de la demande énergétique ainsi que les problèmes économiques, politiques et environnementaux liés aux combustibles fossiles ont rendu impératif le développement de processus de production de carburants et de produits chimiques renouvelables. La source de carbone durable la plus abondante et la moins chère qui puisse être utilisée comme matière première pour la production de carburants renouvelables et de matières premières chimiques est la biomasse lignocellulosique. Le liquide produit à partir de la pyrolyse de la biomasse est appelé huile de pyrolyse ou bio-huile. Ce liquide contient un mélange complexe de composés résultant de la dégradation d'unités de construction de la biomasse, cellulose, hémicellulose et la lignine. Il a un faible pouvoir calorifique et une teneur élevée en oxygène. Il est acide et contient des particules de charbon solide. Il est donc incompatible avec les carburants actuels à base de pétrole, est thermiquement instable et se dégrade avec le temps. Par conséquent, la valorisation de la bio-huile est inévitable afin de résoudre les problèmes associés aux huiles de pyrolyse et de les utiliser comme carburants et produits chimiques renouvelables. La désoxygénation catalytique est l'une des méthodes prometteuses qui ont été largement étudiées afin d'éliminer l'oxygène atomique et de valoriser ces huiles. Cependant, il y a encore plusieurs problèmes tels qu'une faible sélectivité en aromatiques et oléfines et la formation de coke. Ainsi, le développement de nouveaux catalyseurs et procédés est indispensable pour surmonter les préoccupations mentionnées. Dans la première partie de cette thèse, la synthèse et la caractérisation d'une série d'échantillons de ZSM-5 mésoporeux sont discutées. Le copolymère tribloc Pluronic P123 (EO20PO70EO20) a été utilisé comme matrice de phase méso et la synthèse a été suivie par une méthode d'ajustement du pH permettant d'obtenir un matériau ZSM-5 bien cristallisé avec des méso-canaux de taille 8-10 nm. Les matériaux résultants ont été caractérisés par diffraction des rayons X, microscopie électronique à transmission (TEM), adsorption / désorption d'azote, microscopie électronique à balayage (MEB), résonance magnétique nucléaire à l'état solide (MAS-RMN) et désorption en température programmée de l'ammoniac (TPD). La difficulté de la méthode développée est d'effectuer la croissance de cristaux de zéolithe avec un réseau de pores mésostructuré d'une manière coopérative, en évitant à la fois une séparation de phase entre les unités de surfactant et de zéolithe pendant la cristallisation et la formation d'un matériau mésoporeux amorphe séparé. Dans la deuxième partie, l'effet de la mésoporosité sur la désoxygénation du furane en termes de production d’aromatiques et de désactivation du catalyseur par une étude comparative entre des échantillons de ZSM-5 mésoporeux et microporeux, est étudié. Les catalyseurs mésoporeux ont été préparés selon le procédé décrit dans la première partie avec des rapports Si / Al de 30 et 60. De plus, deux taux différents de WHSV de 5,5 et 11 h-1 ont été utilisés dans les essais. On a trouvé que le taux de conversion du furane initial était plus élevé pour les catalyseurs microporeux, qui se désactivaient cependant rapidement, sur 2 heures de fonctionnement. D'autre part, les catalyseurs mésoporeux ont montré une activité plus régulière avec une légère vitesse de désactivation. La sélectivité globale en aromatiques par rapport aux catalyseurs mésoporeux était plus élevée que par rapport à celle des catalyseurs microporeux. Au chapitre 4, l'effet de l'incorporation de sites actifs métalliques (Zn) sur les taux de conversion du furane, la production d'aromatiques et la formation de coke est discuté. Deux séries de catalyseurs microporeux et mésoporeux avec Si / Al = 30 ont été préparées à différentes charges métalliques de 2 et 5% en poids. Les résultats de la caractérisation par diffraction des rayons X (XRD) n'ont révélé aucun pic supplémentaire par rapport au spectre de la zéolithe, indiquant la bonne dispersion du zinc. Le taux initial de conversion de furane était plus élevé pour les catalyseurs microporeux; il augmentait avec une augmentation de la charge de métal, mais les échantillons mésoporeux se sont rapidement désactivés après 2 heures de fonctionnement. De plus, la sélectivité en aromatiques avec le benzène comme produit principal a été augmentée et la formation de coke a été réduite pour les échantillons mésostructurés.
Depleting fossil fuel reserves and increase of energy demands along with economical,political, and environmental issues related to the fossil fuels have made it imperative to develop processes to produce renewable fuels and chemicals. The most plentiful and cheap sustainable source of carbon that can be used as a feedstock for the production of renewable fuels and commodity chemical feedstocks is lignocellulosic biomass. The liquid produced from the pyrolysis of biomass is designated as pyrolysis oil or bio-oil. This liquid contains acomplex mixture of compounds resulting from the degradation of biomass building units,cellulose, hemicellulose, and lignin. It has a low heating value and high oxygen content, isacidic, contains solid char particles, is incompatible with current petroleum-based fuels, isthermally unstable, and degrades with time. Therefore, upgrading of bio-oil is inevitable inorder to resolve the issues associated with pyrolysis oils and to use them as renewable fuelsand chemicals. Catalytic deoxygenation is one the promising methods which have been extensively studied in order to remove atomic oxygen and valorizing these oils. However, there are still several issues such as low selectivity into aromatics and olefins and coke formation. Thus, developing new catalysts and processes is a must to overcome the mentioned concerns.In the first part of this thesis, the synthesis and characterization of a series of mesoporousZSM-5 samples are discussed. Pluronic P123 triblock copolymer (EO20PO70EO20) was used as the meso-phase template and synthesis was followed by a pH adjusting methodallowing obtaining a well-crystallized ZSM-5 material with meso-channels of size of 8-10nm. The resulting materials were characterized using X-ray diffraction, transmission electronmicroscopy (TEM), nitrogen adsorption/desorption, scanning electron microscopy (SEM),solid-state nuclear magnetic resonance (MAS-NMR) and ammonia temperature programmed desorption (TPD) analyses. The significance of the developed method is to perform the growth of zeolite crystals with a mesostructured pore lattice in a cooperative manner,avoiding both a phase separation between the surfactant and zeolite units during crystallization and the formation of a separate amorphous mesoporous material. In the second part, the effect of mesoporosity on deoxygenation of furan in terms of aromatic production and catalyst deactivation through a comparative study between mesoporous andmicroporous ZSM-5 samples, is studied. The mesoporous catalysts were prepared accordingto the method described in part one with Si/Al ratios of 30 and 60. Moreover, two differentWHSV rates of 5.5 and 11 h-1 were employed in the reaction tests. It was found that the initialfuran conversion was higher over the microporous catalysts, which however deactivated rapidly, over 2 hours of time on-stream. On the other hand, the mesoporous catalysts showeda steadier activity with a slight deactivation rate. The overall selectivity to aromatics over the mesoporous catalysts was higher than over the microporous ones. In chapter 4, the effect of the incorporation of zinc metallic active sites on the conversion,aromatic production and coke formation rates is discussed. Two series of microporous and mesoporous catalyst with Si/Al=30 were prepared at different metal loadings of 2 and 5 wt.%.The results of X-ray diffraction (XRD) patterns revealed no extra peaks compared to thoseof the Zn free materials, indicating the good dispersion of zinc. The initial furan conversionrate was higher over the microporous catalysts, and increased by increasing the metal loading,however the microporous samples, deactivated rapidly after 2 hours of time on-stream. Inaddition, the aromatic selectivity with benzene as the major product was increased and coke formation was reduced over the mesostructured zeolites.

An Ultraviolet to Visible (UV-Vis) spectroscopic analysis based on fuzzy logic approach has been developed for furan content measurement in transformer oil. Following the successful identification and quantification of furan derivatives in transformer oil by ASTM D5837 standard, the new approach is able to approximate the furan content more conveniently and economically. As furan concentration level would determine the absorption intensity in UV-Vis spectral range, the fuzzy logic software model developed would exploit this characteristic to aggregate the furans content level in transformer oil. The UV-Vis spectral response at other ambient temperature is also studied. The proposed technique provides a convenient alternative to conventional method of furan measurement by High Performance Liquid Chromatography (HPLC) or Gas Chromatography Mass Spectrometry (GC/MS) in ASTM D5837 Standard.

The catalytic activity of ruthenium(II) bis(diimine) complexes cis-[Ru(6,6′-Cl2bpy)2(OH2)2](Z)2 (2, Z = CF3SO3; 3, Z = (3,5-(CF3)2C6H3)4B ,i.e. BArF), cis-[Ru(4,4′-Cl2bpy)2(OH2)2](Z)2 (4, Z = CF3SO3; 5, Z = BArF) and cis-[Ru(bpy)2(PR3)(OH2)](CF3SO3)2 (7, bpy = 2,2’-bipyridine, PR3 = P(C6H4F)3; 8, bpy = 2,2-bipyridine, PR3 = PPh3; 9, bpy = 4,4’-dichloro-2,2’-bipyridine, PR3 = PPh3; 10, bpy = 4,4’-dimethyl-2,2’-bipyridine, PR3 = P(C6H4F)3) for the hydrogenation and hydrogenolysis of furfural (FFR), furfuryl alcohol (FFA) and 5-hydroxymethylfurfural (HMF) was investigated. The compounds 2-5 are active and highly selective catalysts for the hydrogenation of FFR to FFA. Using 2 as catalyst at 100 °C, hydrogenation of FFR proceeded to high conversion (≥98%) and with 100% selectivity to FFA in 2 h. The catalyst cis-[Ru(6,6′-Cl2bpy)2(OH2)2](CF3SO3)2 (2) also showed some activity for hydrogenolysis of FFR and FFA at 130 °C in ethanol, giving up to 25% of 2-methylfuran (MF) yield. The catalyst 3 alsodisplayed high catalytic activity for the hydrogenation of FFA to tetrahydrofurfuryl alcohol. Catalysts 7-10 are also active towards the hydrogenation of furfural (FFR) in NMP giving >90% FFR conversion with 100% selectivity for furfuryl alcohol (FFA) in 12 h. Compounds 7-10 are active C-O bond hydrogenolysis catalysts in presence of bismuth halide Lewis acids. For example, hydrogenolysis of FFA in the presence of 1 mol% of catalyst cis-[Ru(4,4’-Cl2bpy)2(PPh3)(OH2)](CF3SO3)2 (9) and 20 mol% bismuth bromide at 180 °C/51 atm H2 pressure gave >96% conversion of FFA and 55% MF yield. Compounds 7-10 in the presence of bismuth halides, showed almost 100% conversion of HMF with a very high selectivity (65-72%) for 2,5-DMF, along with 10-12% of MF, and trace amount of 5-methylfurfural (MeFFR). In order to test the activity of ruthenium hydrides towards the C-O bond hydrogenation and hydrogenolysis of HMF, series of monocationic ruthenium complexes cis-[Ru(bpy)2(PR3)(H)](CF3SO3) (12, bpy = 2,2’-bipyridine, PR3 = P(C6H4F)3; 13, bpy = 2,2-bipyridine, PR3= PPh3; 14, bpy = 4,4’-dimethyl-2,2’-bipyridine, PR3= P(C6H4F)3) were prepared. The hydrogenation of HMF using catalysts 12-14, produced 70-72% of 2,5-DMF and 11% MF, suggesting that ruthenium hydrides are active and efficient catalysts for HMF hydrogenation.

The spray and combustion characteristics of the new bio-fuel candidates, 2,5-dimethylfuran (known as DMF) and 2-methylfuran (known as MF), are examined using optical diagnostic methods. A macroscopic spray characteristics study using high speed imaging has been performed to gain the understanding of the bio-fuels’ spray behavior under various conditions compared to gasoline and isooctane. The droplet sizes of the bio-fuel injections under different operating conditions are also studied using Phase Doppler Particle Analyzer (PDPA). The laminar flame propagation and the turbulent flame propagation for MF and DMF have been benchmarked against isooctane.

An interesting insight has been developed into the roles of a paralogous pair of transcriptional regulators MmfR and MmyR in the regulation of methylenomycin antibiotic biosynthesis in Streptomyces coelicolor. Research involved the development and use of a luciferase reporter assay, optimised for use in GC high bacteria. MmfR belongs to the TetR-family of transcriptional repressor proteins and works as a single component system, binding to DNA at one of three methylenomycin auto-regulatory response element (MARE) operators. Here it represses transcription of five different operons until a conformational change is brought about by specific binding to one of five small signalling molecules; the methylenomycin furans (MMFs). This investigation revealed that the five different MmfR-regulated operons have promoters of differing strengths, which is also contributed to by a variation in the strength of MmfR binding to the three MARE operator sites. Each of the five naturally produced MMF ligands were also shown to have a different efficacy for deactivating and displacing MmfR. An in silico analysis of the MmfR primary and tertiary structures, followed by in vivo mutagenesis, revealed the presence of two tyrosine residues implicated in ligand binding. The paralogue MmyR was shown to vary in activity from that of MmfR. It showed weaker, but significant binding to only two out of the three MARE operator sites, binding with different affinities to each, and no significant removal of repression was seen in the presence of the MMF ligands. The MmfR/MMF/MARE operator system shows promise as something that can be developed into a novel inducible expression system for use in GC high bacteria. However, whether this system can be adapted to be efficient in multiple hosts is yet to be seen, with affinity for the MARE operators from exogenous regulatory proteins predicted.

This thesis describes the chemistry developed during a study of novel transition metal-catalysed reactions. Chapter 2 describes a novel procedure for the synthesis of 2,5-disubstituted furans via the isomerisation of 1,4-alkyne diols, avoiding the pitfalls of the traditional Paal-Knorr reaction. The initial ruthenium catalysed isomerisation is followed by an in situ cyclocondensation reaction using an acid co-catalyst in a one step route to furan derivatives. In addition the synthesis of the 1,4-dicarbonyl surrogates, 1,4-alkyne diols, is detailed. The methodology detailed in chapter 2 is then used in the synthesis of pyrrole derivatives in Chapter 3. Replacement of the acid co-catalyst with 2 equivalents of amine allow various pyrrole derivatives to be synthesised using the 1,4-alkynediols as starting materials. Various amines can also be used from anilines, benzylamines and aliphatic amines, allowing access to a wide range of products.

In this study, a novel series of conjugated monomers containing furan and fluorene units
2,7-di(furan-2-yl)-9H-fluoren-9-one (FOF), 2-(2-(furan-2-yl)-9H-fluoren-7-yl)furan (FFF), and 2-(2-(furan-2-yl)-9,9-dihexyl-9H-fluoren-7-yl)furan (FHF) were synthesized and their electrochemical polymerization were achieved via potential cycling. Optical and electrochemical properties of the polymers, poly(2,7-di(furan-2-yl)-9H-fluoren-9-one) (PFOF), poly(2-(2-(furan-2-yl)-9H-fluoren-7-yl)furan (PFFF) and poly(2-(2-(furan-2-yl)-9,9-dihexyl-9H-fluoren-7-yl)furan) (PFHF) were investigated and it was found that polymer films exhibit reversible redox behavior (Epox = 1.083 V for PFOF, Epox= 0.915 V for PFFF and Epox= 0.985 V for PFHF) accompanied with a reversible electrochromic behavior, orange to green for PFOF, yellow to dark blue for PFFF and orange to green for PFHF during oxidation. Their band gap values (Eg) were found to be 2.32, 2.49 and 2.61 eV for PFOF, PFFF and PFHF, respectively.