Dissertations / Theses on the topic 'Aromatic hydrogen'

A series of new “frustrated Lewis pairs” (FLPs), including chiral versions, with a predefined spatial relationship between the basic and acidic centers is proposed. Several synthetic protocols toward the targets were investigated: through an aryllithium-haloborane coupling; using organotin reagents and a chiral diazaborolidine; and through organoboranes RBH₂ as the boron component. Further development of the project is discussed in light of the discovered data. The intermolecular system consisting of 8-bromo-2-methylquinoline and (C₆F₅)₃B was shown to exist in the form of an FLP. This FLP is not capable of heterolytic H-H bond cleavage with formation of an isolable adduct either at 1 atm or at 4 atm of H₂.

A series of para-substituted phenylethylamine analogues bound to the enzyme aromatic amine dehydrogenase have been simulated using quantum mechanical electronic structure calculations and molecular mechanical molecular dynamics simulations. Trends have been verified connecting bond dissociation energy (and thus driving force) to observed rate constants and activation enthalpy. Trends have been identified in connecting statistics drawn from molecular dynamics simulations and the temperature dependence of the kinetic isotope effect, notably that as the temperature dependence of the kinetic isotope effect increases the flexibility of the promoting vibration decreases. This is explained as being more effected by thermal energy put into the system, and therefore more affected by temperature.

Au niveau moléculaire, les fonctions des motifs hélicoïdaux sont souvent associées à la stabilité de cesarchitectures. Par exemple, lorsqu’une hélice α est isolée de la structure tertiaire des protéines, celle-cidevient alors flexible et perd son activité. Afin de contrôler la rigidité de ces architectures, différentesapproches ont été proposées dont la construction d’édifices moléculaires repliés de façon contrôlée : lesfoldamères. Notre équipe s’intéresse aux foldamères d’oligoamide aromatique hélicoïdaux et à l’heureactuelle plusieurs études ont déjà été menées afin de comprendre les facteurs influant la stabilité de telleshélices: la longueur de l’oligomère, le solvant et l’effet de l’introduction d’un espaceur aliphatique dans laséquence. Lors de ce travail nous nous sommes tout d’abord intéressés à la capacité de repliement de cinqmonomères aromatiques couramment utilisés pour la préparation de foldamères. Leur contribution dans lastabilité hélicoïdale du système a été évaluée par RMN, diffraction des rayons-X et HPLC chirale dynamique.Inspirés par le rôle des ponts disulfure dans les protéines, nous avons décidé d’explorer l’effet d’une telleliaison sur la stabilité des hélices d’oligoamide aromatique. Deux composés contenant une liaison disulfureintramoléculaire ou deux liaisons intermoléculaires ont été synthétisés et leur stabilité étudiée par RMN, HPLCChiral et Dichroïsme circulaire.Enfin, la synthèse d’hélices moléculaires de grandes dimensions (assimilables à celles de polymèresmonodisperses) a été réalisée par une approche convergente de triplement de longueur de segment via laformation de liaisons anhydrides entre blocs oligomériques<br>At the molecular level, the functions of helical patterns are often directly associated with the stability of thesearchitectures, (in α-helices). For example, upon removal of such an entity from the protein’s tertiary structure,the peptidic helix becomes flexible and thus inactive. In order to control the rigidity of these architectures,several strategies have been used and the construction of completely artificial well folded molecules known asfoldamers is one them. Our group mainly focuses on helical aromatic oligoamide foldamers and to dateseveral studies have been carried out to investigate factors affecting the helical stability; the influence ofoligomer length, solvent effects and the effect of aliphatic linkers within a helical aromatic sequence.In the present study we investigate the helical propensity of five commonly used aromatic monomers infoldamer synthesis and by using NMR spectroscopy, X-ray crystallography and dynamic chiral HPLC weevaluate their contribution in helical stability. Additionally, inspired by the role of disulfide bonds in proteins wedecided to explore their effect on helical stability. For this reason intra- and inter-molecularly disulfide bondedcompounds were designed and synthesized. Their stability was studied using NMR spectroscopy, chiral HPLCand CD experiments.Finally, the synthesis of mono-disperse helical strings of polymeric dimensions through a convergent, segmenttripling strategy has been developed. This protection/deprotection free synthesis was carried out byconnecting oligomeric blocks via a labile anhydride functionality

Fullerenization as process of thermal (750-1000°С) of transformation of aliphatic and aromatic hydrocarbons molecules in molecules of quasi-fulleranes (CnHn-6–CnHn-2 (n=20–54)) and fulleranes (in particular, the equiatomic composition C60H60) was performed for the first time. Main feature of fullerenization process is, that its products are formed in all volume of reactionary space, but are located (are deposited and are condensed) in it a low-temperature zone. Extracted from pyrolytic soot the products of benzene and nhexane fullerenization contain the condensed molecules containing up to 4.8 and 5.1 % of hydrogen accordingly, which allocation at thermolysis is began with 50ºС and proceeds up to 750ºС. Products of benzene and n-hexane fullerenization can be perspective for hydrogen storage.

Room-temperature chemisorption of hexacyclic aromatic hydrocarbons on the 2x1, sputtered, oxidized and H-terminated Si(100) surfaces, as well as those upon post treatments of hydrogenation, oxidization and electron irradiation have been investigated by using thermal desorption spectrometry (TDS), Auger electron spectroscopy (AES) and low energy electron diffraction (LEED). This work focuses on the effects of the functional groups (phenyl, methyl, vinyl, heteroatom, and H atom) in the chemisorbed aromatic hydrocarbons (benzene, toluene, xylene isomers, styrene and pyridine) on organic functionalization of the Si(100) surface, particularly on such surface processes as cycloaddition, dative adsorption, hydrogen abstraction, desorption, dissociation, diffusion, and condensation polymerization. Unlike the earlier notion that hydrogen evolution in the hydrocarbon/Si(100) systems is the result of hydrocarbon dissociation (into smaller hydrocarbon fragments and H atoms) on the surface, condensation polymerization of the adsorbed aromatic hydrocarbons is proposed in the present work, in order to explain the higher-temperature hydrogen evolution feature in the toluene/Si(100) system. This hypothesis is supported by our TDS results for other hydrocarbon adsorbates, especially in the pyridine/Si(100) system where electron-induced condensation polymerization has been observed at room temperature. The improved techniques in the TDS experiments developed in the present work have enabled us to observe condensation polymerization and the effect of H on the surface processes (via surface reconstruction) on Si(100) for the first time. New analysis methods have also been developed to determine the adsorption coverage from the AES data, and this work has not only improved the accuracy of the elemental-coverage evaluation, but also provided a means to estimate the rate and the order of chemisorption. By using the density functional theory with the Gaussian 98 program, the adsorption geometries and the corresponding adsorption energies of various adsorption phases have been calculated. These computational results have provided useful insights into the chemisorption structures on the Si(100) surface. The present work also presents the development of three kinetics models for hydrogen evolution in the aforementioned aromatic-hydrocarbon systems on Si(100). Based on a modified collision theory with consideration of diffusion, these theoretical models have proven to be quite successful in simulating the observed TDS profiles and in estimating the kinetic parameters for the analysis of condensation polymerization in 2-dimensional diffusion systems. The present work illustrates that TDS experiments can be used effectively with quantum computation and theoretical kinetics modelling to elucidate the intricate nature of organosilicon surface chemistry.

Le trifluoroéthanol (TFE) et l'hexafluoroisopropanol (HFIP) présentent des propriétés physicochimiques particulières comme un fort pouvoir ionisant élevé, une forte capacité à donner des liaisons hydrogène, et une faible nucléophilie. Ces différentes propriétés ont été avantageusement exploitées dans plusieurs réactions sans la présence de catalyseur. Dans un premier temps, l'étude de l'amination électrophile sélective d'aromatiques avec les azodicarboxylates a été réalisée dans l'HFIP pour conduire à une famille d'hydrazines aromatiques. Ensuite l'alkylation de Friedel-Crafts avec des hétéroaromatiques et des β-nitroalcènes a conduit à des dérivées de tryptamines. Ensuite, l'halogénation sélective d'aromatiques et d'hétérocycles en présence de N-halosuccinimides (NIS, NBS et NCS) a été développée. Egalement, nous avons étudié un nouveau système combinant l'HFIP et le KHSO4 qui est un sel inorganique peu coûteux. L'association de l'HFIP et de KHSO4 (10 mol%) est un système catalytique doux et efficace pour promouvoir certaines réactions. En particulier nous avons montré que ce système catalytique a été appliqué avec succès pour l'amination directe d'aromatiques peu activés avec des azodicarboxylates pour conduire à d'autres dérivés hydrazines. Ce système a aussi montré son efficacité dans la réaction directe de benzylation de Friedel-Crafts avec des alcools benzyliques. Ainsi une grande variétés de composés diarylméthanes dissymétriques a pu être obtenue avec une excellente régiosélectivité<br>Due to the electron-withdrawing character of fluoroalkyl groups, fluorinated alcohols such as trifluoroethanol (TFE) and hexafluoroisopropanol (HFIP) exhibit a nearly unique set of properties that include high ionizing power, strong hydrogen bond donating ability, mild acidity, and low nucleophilicity. All of these properties have been exploited without the need of an external catalyst. At first, the para-selective amination of free anilines with azodicarboxylates in HFIP led to hydrazine derivatives. The Friedel-Crafts alkylation of indoles and electron-rich arenes with β-nitroalkenes succeeded to afford tryptamines derivatives. Then the regioselective halogenation of arenes and heterocycles with N-halosuccinimides (NIS, NBS, NCS) have been developed. Meanwhile, we have disclosed a new mild system between HFIP and KHSO4 which is a green, inexpensive and readily available inorganic salt. The association of HFIP/KHSO4 (10 mol%) is an efficient and mild catalytic system in order to promote some reactions. In particular, we showed that this system allowed the direct amination of slightly activated and neutral arenes with azodicarboxylates in order to give other families of hydrazines. This mild system has been applied successfully for the Friedel-Crafts benzylation with benzylic alcohols. These mild conditions provided a straightforward synthesis of a variety of unsymmetrical diarylmethanes in high yield with good to high regioselectivity

The AQUAFAC (Aqueous Functional Group Activity Coefficients) method for predicting aqueous activity coefficients proposed by Myrdal et al. (1992) is expanded to include for hydrogen bonding groups: hydroxy, carboxy, nitro and amino. Activity coefficients can be used to estimate aqueous solubility. Using aqueous solubility data, from a number of sources, for a set of subsituted aromatic compounds, group or q values are derived. Group values have been generated for a number of substituents, none have included hydrogen bonding groups (Myrdal et al., 1992,1993). Q values are related to activity coefficients through the following relationship: log gammaw = Sigmaniqi where log gammaw is the log of the activity coefficient, qi is the group value subtituent i and ni is the group frequency. Ortho effects between hydrogen bonding groups is also examined. Intramoleculat hydrogen bonding involving carboxy substituted compounds, in this research, does appear to affect aqueous solubility.

In this thesis, it has been studied the deamination of aromatic amines, through in situ formed diazonium salts as reaction intermediates, catalyzed by salicylic acid, a nontoxic, eco-friendly and economic catalyst. In the early part of the thesis (Chapter I) it has studied the deamination process using THF as solvent as hydrogen donor and anilines as radical source, to carry the hydrodeamination reaction, as well as the process in its deuterodeamination manner using deuterated solvent. Following with this study in Chapter II and Chapter III, it has been studied the addition of the aromatic radicals, generated with the methodology employed in the first chapter, to different types of double bond, to form α-arylketones (Chapter II) and γ-aryl lactones, throw a following intramolecular cyclization (Chapter III). Finally, in Chapter IV was studied the construction of arylphosphonates, starting from anilines as radical source, and triphenylphosphite, and in this case specially, mechanism was hard explored. In every work, the methodologies could be scaled-up above 1 g, reaction mechanisms were proposed and studied through control and mechanistical experiments, and follow reactions were carried out.

(1) We will show that nano sized samples of SAPO-34 synthesized by microwave heating presents much higher lifetime than standard-SAPO-34 synthesized by conventional hydrothermal method for the reaction of methanol to olefins. (2) We will stabilize the Nano SAPO-34 in the ways such as steaming with water or calcinated in H2 condition. (3) The treatment of mix alkali treatment with proper TPAOH/NaOH could make composites with mesopore and microporous structure in the zeolite ZSM-5 to reduce strong acid quantity and the change the selectivity of the main product. (4) Different 8MR zeolite show different selectivity and lifetime in the same condition in the reaction of methanol to olefins.<br>Li, Z. (2014). New micro and mesoporous materials for the reaction of methanol to olefins [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/44229<br>TESIS

Ce travail a pour objectif d'augmenter la diversité des foldamères par le développement d'une nouvelle classe d'architectures abiotiques mimant le repliement des feuillets β protéiques. La stratégie employée repose sur des processus de structuration qui diffèrent de ceux observés au sein du vivant. Les deux éléments essentiels des systèmes naturels, à savoir la boucle courte et flexible d'acides aminés et les brins β liés entre eux par des liaisons hydrogènes, sont ici substitués respectivement par un coude rigide formé de noyaux aromatiques et par des oligoarylamides plans interagissant par empilement aromatique.Ces objets ont été conçus pour adopter des structures repliées caractérisables en solution par spectroscopie RMN et à l'état solide par diffraction des rayons X. Dans une première partie, l'optimisation du pseudo-coude β et de la séquence des brins, ainsi que l'exploration des premières architectures en feuillet seront étudiées à travers la conception, la synthèse et les études structurales de ces oligoamides et oligoamines aromatiques. Dans une seconde partie, le concept mis en oeuvre sera étendu à la synthèse de foldamères plus élaborés à brins courbés, ouvrant ainsi des perspectives intéressantes vers l'obtention d'architectures toujours plus complexes.

[ES] En este trabajo de tesis doctoral, la investigación se ha centrado en el desarrollo de diferentes procesos catalíticos heterogéneos empleando materiales híbridos orgánico-inorgánicos porosos (MOFs y sílices funcionalizadas) y materiales orgánicos aromáti-cos (PAFs), que se han estudiado en diversas reacciones orgánicas. Tras la preparación de los MOFs en estudio, se han caracterizado sus propiedades estructurales y se han determinado sus centros activos en los clústeres metálicos (circonio, hafnio o cerio). La reactividad de estos MOFs y de los materiales híbridos sílice-aminas se ha estudia-do teniendo en cuenta sus centros catalíticos; estas reacciones se han optimizado lle-vando a cabo un estudio de los mecanismos de reacción. Finalmente, se han preparado sólidos homoquirales de tipo PAF que presentan el sistema binaftilo, cuya reactividad también ha sido probada. Más específicamente, en el capítulo 3 se ha estudiado la esterificación de amidas, que permite convertirlas en ésteres, grupos funcionales más versátiles. Esta transfor-mación se ha abordado desde la catálisis heterogénea via MOFs basados en circonio, hafnio y cerio de las series MOF-808, UiO-66 y MOF-801. El catalizador más eficien-te para la esterificación de amidas ha sido el MOF-808-Zr. Mediante análisis TGA y la adsorción de una molécula sonda básica (CO) estudiada utilizando espectroscopia FT-IR, se han determinado los centros ácidos de Lewis y Brönsted presentes en ellos. De los MOFs preparados en este trabajo, el MOF 808-Zr posee una menor conectividad de los clústeres metálicos y un mayor tamaño de poro mayor que el UiO-66 y el MOF-801; además, tiene el balance adecuado de centros ácidos y básicos de Brönsted y Lewis para activar los sustratos de la reacción. El alcance de la alcoholisis con n-butanol se ha extendido a un gran número de sustratos (amidas primarias, secundarias y terciarias; aromáticas y alifáticas). La reacción también se ha estudiado en condicio-nes no solvolíticas con alcoholes más complejos. El catalizador es estable durante la reacción y puede ser reutilizado fácilmente. El mecanismo de reacción en la esterifica-ción de benzamida con n butanol catalizada por MOF-808-Zr se ha investigado me-diante el análisis cinético empleando el modelo de LHHW y el estudio in situ de las interacciones moleculares por FT-IR. En el capítulo 4, se ha investigado la deuteración por intercambio isotópico deute-rio/hidrógeno catalizada por aminas soportadas en sílice comerciales empleando D2O como fuente de deuterio. Este procedimiento es aplicable a una gran gama de sustra-tos, como compuestos carbonílicos, sales de organofosfonio, nitrocompuestos e, inclu-so, hormonas esteroideas. La estabilidad del catalizador, SiO2-(CH2)3-NH2, se mantie-ne hasta en 10 usos de reacción sin pérdidas significativas de la actividad. Por último, en el capítulo 5, se afronta la síntesis y aplicación de PAFs homoquira-les donde se ha integrado el esqueleto del BINOL (1,1′-binaftil-2,2′-diol) y del BIN-BAM (1,1' binaftil-2,2'-disulfonimida) generando tres nuevos PAFs activos en catáli-sis asimétrica: PAF-3,3'-(S)-BINOL, PAF-6,6'-(R)-BINOL y PAF 3,3'-(S)-BINBAM. En concreto, el PAF-6,6'-(R)-BINOL ha demostrado su actividad catalítica en la reacción de alquilación de aldehídos aromáticos con dietil-zinc y el catalizador PAF-3,3'-(S)-BINBAM es activo en la reacción aldólica de Mukaiyama y la reducción del doble enlace de compuestos carbonílicos a,b-insaturados.<br>[CA] En aquesta tesi doctoral, la investigació s'ha centrat en el desenvolupament de dife-rents processos catalítics heterogenis emprant materials híbrids orgànic-inorgànics porosos (MOFs i sílices funcionalitzades) i materials orgànics aromàtics (PAFs), que s'han estudiat en diverses reaccions orgàniques. Després de la preparació dels MOFs en estudi, s'han caracteritzat les seues propietats estructurals i s'han determinat els seus centres actius en els clústers metàl·lics (zirconi, hafni o ceri). La reactivitat d'aquests MOFs i dels materials híbrids sílice-amines s'ha estudiat tenint en compte els seus cen-tres catalítics; aquestes reaccions s'han optimitzat duent a termini un estudi dels meca-nismes de reacció. Finalment, s'han preparat sòlids homoquirals de tipus PAF que presenten el sistema binaftilo, la reactivitat del qual també ha sigut provada. Més específicament, en el capítol 3 s'ha estudiat l'esterificació d' amides, que per-met convertir-les en èsters, grups funcionals més versàtils. Aquesta transformació s'ha abordat des de la catàlisi heterogènia via *MOFs basats en zirconi, hafni i ceri de les sèries MOF-808, UiO-66 i MOF-801. El catalitzador més eficient per a l'esterificació d'amides ha sigut el MOF-808-Zr. Mitjançant anàlisi TGA i l'adsorció d'una molècula sonda bàsica (CO) estudiada utilitzant espectroscopia FT-IR, s'han determinat els cen-tres àcids de Lewis i Brönsted presents en ells. Dels MOFs preparats en aquest treball, el MOF 808-Zr posseeix una menor connectivitat dels clústers metàl·lics i una major grandària de porus que el UiO-66 i el MOF-801; a més, té el balanç adequat de centres àcids i bàsics de Brönsted i Lewis per a activar els substrats de la reacció. L'abast de l'alcoholisi amb n-butanol s'ha estés a un gran nombre de substrats (amides primàries, secundàries i terciàries; aromàtiques i alifàtiques). La reacció també s'ha estudiat en condicions no solvolítiques amb alcohols més complexos. El catalitzador és estable durant la reacció i pot ser reutilitzat fàcilment. El mecanisme de reacció en l'esterifica-ció de benzamida amb n-butanol catalitzada per MOF-808-Zr s'ha investigat mitja-nçant l'anàlisi cinètica emprant el model de LHHW i l'estudi in situ de les interaccions moleculars per FT-IR. En el capítol 4, s'ha investigat la deuteració per intercanvi isotòpic deuteri/hidrògen catalitzada per amines suportades en sílices comercials emprant D2O com a font de deuteri. Aquest procediment és aplicable a una gran gamma de substrats, com a com-postos carbonílics, sals d'organofosfoni, nitrocompostos i, inclosa, hormones esteroi-dals. L'estabilitat del catalitzador, SiO2-(CH2)3-NH2, es manté fins a 10 usos de reac-ció sense pèrdues significatives de l'activitat. Finalment, en el capítol 5, s'afronta la síntesi i aplicació de PAFs homoquirals on s'ha integrat l'esquelet del BINOL (1,1′-binaftil-2,2′-diol) i del BINBAM (1,1'-binaftil-2,2'-disulfonimida) generant tres nous PAFs actius en catàlisi asimètrica: PAF-3,3'-(S)-BINOL, PAF-6,6'-(R)-BINOL i PAF 3,3'-(S)-BINBAM. En concret, el PAF-6,6'-(R)-BINOL ha demostrat la seua activitat catalítica en la reacció d'alquilació d'aldehids aromàtics amb dietil-zinc i el catalitzador PAF-3,3'-(S)-BINBAM és actiu en la reacció aldólica de Mukaiyama i la reducció del doble enllaç de compostos carbonílics a,b-insaturats.<br>[EN] In this Doctoral Thesis, the research has been focused on the development of different heterogeneous catalytic processes using hybrid porous organic-inorganic materials (MOFs and functionalized silicas) and organic aromatic materials (PAFs), which have been studied in various organic reactions. After the preparation of the MOFs under study, their structural properties have been characterised and their active centres in the metal clusters (zirconium, hafnium or cerium) have been determined. The reactivity of these MOFs and the hybrid silica-mine materials has been studied considering their catalytic centres; these reactions have been optimised by carrying out a study of the reaction mechanisms. Finally, homochiral PAF-type solids have been prepared with the binafil system, whose reactivity has also been tested. More specifically, the esterification of amides has been studied in Chapter 3. This reaction allows to convert the amides into esters, which are more versatile functional groups. This transformation has been approached from the heterogeneous catalysis via MOFs based on zirconium, hafnium and cerium of the MOF-808, UiO-66 and MOF-801 series. The most efficient catalyst for amide esterification has been MOF-808-Zr. Using TGA analysis and the adsorption of a basic probe molecule (CO) studied using FT-IR spectroscopy, the acid centres of Lewis and Brönsted present in them have been determined. Among the MOFs prepared in this work, MOF 808-Zr has a lower metal cluster connectivity and a larger pore size than UiO-66 and MOF-801; it also has the appropriate balance of acid and basic Brönsted and Lewis centres to activate the reaction substrates. The scope of n-butanol alcoholysis has been extended to a large number of substrates (primary, secondary and tertiary amides; aromatic and aliphatic). The reaction has also been studied in non-solvolitic conditions with more complex alco-hols. The catalyst is stable during the reaction and can be easily reused. The reaction mechanism in the esterification of benzamide with n-butanol catalysed by MOF-808-Zr has been investigated through kinetic analysis using the LHHW model and the in situ study of molecular interactions by FT-IR. In Chapter 4, the deuteration by isotopic deuterium/hydrogen exchange catalysed by commercial silica-supported amines using D2O as a source of deuterium has been investigated. This procedure is applicable to a wide range of substrates, such as carbonylic compounds, organophosphonium salts, nitro compounds and, even, steroid hormones. The stability of the catalyst, SiO2-(CH2)3-NH2, is maintained for up to 10 reaction uses without significant loss of activity. Finally, in Chapter 5, the synthesis and application of homochiral PAFs, in which the structure of BINOL (1,1′-binaftil-2,2′-diol) and BIN-BAM (1,1' binaftil-2,2'-disulfonimide) has been integrated, is discussed. Three new PAFs active in asymmetric catalysis has been generated: PAF-3,3'-(S)-BINOL, PAF-6,6'-(R)-BINOL and PAF 3,3'-(S)-BINBAM. In particular, PAF-6,6'-(R)-BINOL has demonstrated its catalytic activity in the alkylation reaction of aromatic aldehydes with diethyl zinc and the catalyst PAF-3,3'-(S)-BINBAM is active in the Mukaiyama aldolic reaction and the reduction of the double bond of carbonylic a,b-unsaturated compounds.<br>Villoria Del Álamo, B. (2021). Síntesis de catalizadores sólidos orgánicos e híbridos orgánicos-inorgánicos y su aplicación [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/163789<br>TESIS

Les travaux de thèse présentés sont issus d’une collaboration industrielle avec la société Nouvelle Sogatra, spécialisée dans la conception, la fabrication et la commercialisation de revêtements de protection bi-composants répondant aux normes d’alimentarité. L’objectif principal de ce projet est de proposer de nouveaux revêtements époxydiques performants en utilisant des produits biosourcés et, dans l’idéal, moins dangereux pour l’Homme et pour l’environnement. Ces travaux de thèse s’axent autour de l’identification de nouvelles méthodologies de synthèse de durcisseurs aminés biosourcés qui soient facilement applicables industriellement.L’amination directe des groupements époxy par ouverture de cycle en présence d’ammoniaque ainsi que l’amination réductrice via la synthèse d’imine ont été sélectionnées comme voies de synthèse pour leur facilité d’application et leur caractère respectueux de l’environnement. Pour cela, des précurseurs commerciaux biosourcés et/ou à toxicité réduite ont été sélectionnés. De nouveaux durcisseurs aminés ont été synthétisés à partir de bio ressources telles que la vanilline, le cardanol et le benzaldéhyde. Ces durcisseurs ont ensuite été utilisés pour la synthèse de système époxy-amine thermodurcissables dont les propriétés physico-chimiques et thermodynamiques ont été caractérisées<br>The presented PhD works were initiated by an industrial collaboration with the company Nouvelle Sogatra, specialized in the design, manufacturing and marketing of two component protective coatings for food contact. The aim of this project is to offer new high-performance epoxy thermosets from bio based reactants and, ideally with a low impact on the health and the environment. This PhD works focus on the identification of new synthesis methodologies of bio-based amine hardeners, which could be easily industrialized.The direct epoxy amination by ring opening using ammonia and the reductive amination via imine synthesis were selected as synthesis routes for their simple utilization and their eco friendly character. Hence, bio based and/or reduced toxicity commercial precursors were selected. New amine hardeners were synthesized from bio resources, such as vanillin, cardanol and benzaldehyde. These hardeners were then used to synthesize epoxy-amine thermosets, whose thermomechanical and physicochemical properties were characterized

Preparation de nitriles a partir d'amines primaires et d'alpha -aminoacides. Les acides amines monosubstutitues rch(nh::(2))co::(2)h donnent le nitrile rcn, alors que les acides amines disubstitues rr'c(nh::(2))co::(2)h conduisent a l'azine rr'c=n-n=cr'r. Les mecanismes proposes font intervenir le cuivre (iii), forme in situ a partir du cuivre (i) et de l'oxygene

In der vorliegenden Arbeit wird die Synthese und Charakterisierung von chiralen prolylfunktionalisierten Farbstoffen vorgestellt. Als chromophore Schlüsselverbindungen wurden Nitroaniline aber auch größere push-pull pi-Systeme wie Schiffsche Basen, Azofarbstoffe und Merocyanine gewählt. Im Fokus dieser Arbeit stehen dabei deren solvatochrome Eigenschaften, pH-Sensitivität sowie mögliche Wechselwirkung mit Biomolekülen und verschiedenen An- und Kationen. Zusätzlich erfolgten Umsetzungen ausgewählter prolylfunktionalisierter chromophorer Bausteine zu Estern und Amiden. Der Einfluss des Prolylbausteins auf das im Festkörper ausgebildete Wasserstoffbrückenbindungsmusters wurde über Einkristallröntgenstrukturanalysen untersucht und nach der Graph Set Methode von Etter klassifiziert. Neben der Einkristallröntgenstrukturanalyse erfolgte die weitere Untersuchung der Festkörpereigenschaften mit Hilfe von UV/Vis- sowie NMR-spektroskopischen Methoden. Das solvatochrome Verhalten der prolylfunktionalisierten Verbindungen wurde mittels multipler linearer Regressionsanalyse gemäß der LSER- (linear solvation energy relationship) Beziehung nach den Ansätzen von Kamlet-Taft und Catalán beschrieben und vergleichend interpretiert.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPES<br>Due to the negative aspects obtained by the discriminated use of chemical insecticides, essential oils appear as a natural alternative in the control of the Ae Aegypti mosquito. However, these oils present some limitations that can be overcome through the use of microemulsions (MEs) that increase the solubilization of the active principle and stability of the system. The combination of MEs with polymeric hydrogels can further preserve the structure in aqueous medium. Thus, the objective of this work was to develop and characterize MEs with essential oil of Syzygium aromaticum (OESA) dispersed in hydrogels based on poly (hydroxyethyl methacrylate), p (HEMA). OESA has as main component eugenol that has potential larvicidal effect against the mosquito Aedes aegypti. We sought a system that in aqueous media allows the active principle release, enabling a reduction in the proliferation of the mosquito vector. The ME preparation consisted from OESA, Tween 80 (surfactant) and water. The incorporation of an inorganic phase from methacryloxypropyltrimethoxysilane (MPTS) and ethylene glycol dimethacrylate crosslinking agent (EDGMA) influenced the final structure of the polymeric hydrogels favoring the formation of more rigid and crosslinked polymers, increasing the stability thermal, but decreasing the capacity of water uptake (swelling). The water uptake in the system influences the release kinetics in matrix systems. The composition of the hydrogels influenced the mortality rates of Ae. aegypti in the first 24 hrs, ranging from 11.6 to 66.6% depending on the combination of whether or not MPTS and EDGMA were present in the sample. The hydrogels presented prolonged larvicidal action up to 48 hours, ranging from 30 to 81.6% of the mortality index of the larvae. In this way, the system proved to be promising for prolonged larvicidal action.<br>Devido aos aspectos negativos associados ao uso indiscriminado de inseticidas químicos, os óleos essenciais surgem como alternativa natural no controle do mosquito Ae Aegypti. No entanto, estes óleos apresentam algumas limitações que podem ser superadas a partir da utilização de microemulsões (MEs) que possibilitam o aumento da solubilização do princípio ativo e estabilidade do sistema. A combinação de MEs com hidrogéis poliméricos pode ainda preservar a estrutura em meio aquoso. Desta forma, o objetivo deste trabalho foi desenvolver e caracterizar MEs com óleo essencial de Syzygium aromaticum (OESA) dispersas em hidrogéis a base de poli (metacrilato de hidroxietila), p(HEMA). OESA tem como principal componente o eugenol que possui potencial efeito larvicida contra o mosquito Aedes aegypti. Buscou-se um sistema que em meio aquoso possibilite a liberação do princípio ativo, possibilitando uma redução na proliferação do mosquito vetor. A preparação da ME consistiu na mistura de OESA, tensoativo Tween 80 e água. A incorporação de uma fase inorgânica a partir do metacrilóxi-propiltrimetóxisilano (MPTS) e de agente reticulante dimetacrilato de etileno glicol (EDGMA) influenciou na estrutura final dos hidrogéis poliméricos favorecendo a formação de polímeros mais rígidos e com cadeia reticulada, aumentando a estabilidade térmica, porém diminuindo a capacidade de captação de água (intumescimento). A absorção de água no sistema influencia na cinética de liberação em sistemas matriciais. A composição dos hidrogéis influenciou nos índices de mortalidade das larvas de Ae. aegypti nas primeiras 24 hs, variando de 11,6 a 66,6 % dependendo da combinação presente ou não de MPTS e EDGMA na amostra. Os hidrogéis apresentaram ação larvicida prolongada até 48 hs, variando de 30 a 81,6 % o índice de mortalidade das larvas. Desta forma, o sistema se mostrou promissor para uma ação larvicida prolongada.<br>São Cristóvão, SE

Ce manuscrit présente les résultats d'une étude expérimentale et théorique de deux systèmes moléculaires d'intérêt environnemental : la 2',3-dihydroxyflavone (2'3HF) et les hydrocarbures aromatiques polycycliques (HAP). Ces systèmes ont été étudiés par une combinaison de techniques de spectroscopies électroniques (absorption et fluorescence) et de calculs de chimie quantique (DFT et TD-DFT). Dans une première partie de cette thèse, il est montré que la 2'3HF présente des propriétés acido-basiques singulières par rapport aux autres flavonols. La diminution de plusieurs unités de la valeur du pKa est attribuée à la présence d'un réseau de liaisons hydrogènes. A l'état-excité, un transfert de proton intramoléculaire est à l'origine d'une fluorescence duale. Une bande d'émission supplémentaire, semblant provenir d'une forme tautomère perturbée par interaction avec le solvant, a été mise en évidence. Enfin, une étude exhaustive des complexes de Ca(II), Mn(II) et Zn(II) a montré la formation de chélates avec la fonction α-hydroxycétone. Dans la deuxième partie, trois hypothèses structurales pour expliquer l'observation expérimentale de fluorescence induite par laser (LIF) dans le visible ont été explorées. Une étude sur les dimères de van der Waals (vdW) des HAPs a permis de mieux comprendre la nature de l'interaction entre monomères et de mettre en évidence la difficulté de modéliser ces systèmes, cependant, les transitions électroniques calculées suggèrent que ces espèces ne peuvent pas être responsables des signaux de LIF. Ensuite, une étude identique de HAP liés par ponts aliphatiques a montré des résultats très similaires aux dimères de vdW, excluant leur implication dans la fluorescence observée. Enfin, l'hypothèse de l'émission provenant de radicaux de HAPs a été explorée. Cette dernière est très prometteuse et ouvre la voie à des études expérimentales et théoriques ultérieures<br>This manuscript reports the results of an experimental and theoretical study of two molecular systems of environmental interest: 2',3-dihydroxyflavone (2'3HF) and polycyclic aromatic hydrocarbons (PAH). These systems were studied by a combination of electronic spectroscopic techniques (absorption and fluorescence) and quantum chemical calculations (DFT and TD-DFT). In the first part of this thesis, it is shown that 2'3HF has singular acid-base properties compared to other flavonols. The decrease of the pKa by several units is attributed to the presence of a hydrogen-bond network. In the excited state, an intramolecular proton transfer causes a dual fluorescence. An additional emission band, seemingly originating from a tautomeric form perturbed by interaction with the solvent, was revealed. Finally, an exhaustive study of the Ca(II), Mn(II) and Zn(II) complexes showed the formation of chelates with the α-hydroxyketone function. In the second part, three structural hypotheses to explain the experimental observation of visible-range laser-induced fluorescence (LIF) were explored. A study of van der Waals (vdW) dimers of PAHs provided insights into the nature of the monomer interaction and highlighted the difficulty of modelling these systems. However, the calculated electronic transitions suggest that these species cannot be responsible for the LIF signals. Secondly, an identical study of aliphatically bridged PAHs showed very similar results to vdW dimers, ruling out their involvement in the observed fluorescence. Finally, the hypothesis of emission from PAH radicals was explored. The latter is very promising and opens the way for further experimental and theoretical studies

Au cours de cette thèse, nous nous sommes intéressés à l'activation de liaisons sp² et sp³ C-H catalysée par le palladium pour la préparation d'(hétéro)aryl-aryles et de biaryles. Cette méthode est considérée comme attractive pour l'environnement par rapport aux méthodes classiques, tels que Suzuki, Heck, ou Negishi. Tout d'abord, nous avons décrit que la C2-arylation directe de benzothiophènes peut être effectuée par un catalyseur du palladium en l'absence de ligand phosphine avec une grande sélectivité. Nous avons également démontré qu'il est possible d'activer les positions C2 et C5 de pyrroles pour accéder en une seule étape a des 2,5-diarylpyrroles. Des 2,5-diarylpyrroles non-symétriques ont été formés par arylation séquentielle en C2 suivie par une arylation en C5. Nous avons également étudié la réactivité de polychlorobenzenes pour l'activation de liaisons C-H catalysé au palladium. Nous avons finalement étudié l'activation sp² et sp³ sélective catalysé au palladium de liaisons C-H du guaiazulene. La sélectivité de la réaction dépend du solvant et de la base : C2-arylation (KOAc en éthylbenzène), C3-arylation (KOAc dans le DMAc) et C4-Me arylation (CsOAc/K₂CO₃ dans le DMAc). Grâce à cette méthode, une liaison sp³ C-H peu réactive a été activée<br>During this thesis, we were interested in the sp² and sp³ C-H bond activation catalyzed by palladium catalysts for the preparation of (hetero)aryl-aryls and biaryls. This method is considered as cost effective and environmentally attractive compared to the classical couplings such as Suzuki, Heck, or Negishi. First we described the palladium-catalyzed direct C2-arylation of benzothiophene in the absence of phosphine ligand with high selectivity. We also demonstrated that it is possible to active both C2 and C5 C-H bonds for access to 2,5-diarylated compounds in one step, and also to non-symmetrically substituted 2,5-diarylpyrroles via sequential C2 arylation followed by C5 arylation. We also studied the reactivity of polychlorobenzenes via palladium-catalyzed C-H activation. We finally examined the palladium-catalysed selective sp² and sp³ C-H bond activation of guaiazulene. The selectivity depends on the solvent and base: sp² C2-arylation (KOAc in ethylbenzene), sp² C3-arylation (KOAc in DMAc) and sp³ C4-Me arylation (CsOAc/K₂CO₃ in DMAc). Through this method, a challenging sp³ C-H bond was activated

Die vorliegende Arbeit beschäftigt sich mit der Untersuchung und Beschreibung der Eigenschaften der synthetischen Dekapeptide Cetrorelix und Ozarelix durch analytische Methoden und computergestützte Modellierung. Diese Moleküle sind hydrophobe, aggregierende Antagonisten des Gonadotropin-Releasing-Hormons (GnRH). Zusätzlich wurden amyloidbildende Peptidstrukturen als Modelle für die Assoziationsprozesse in hydrophoben Peptiden untersucht und visualisiert. Die intrinsische Fluoreszenz der GnRH-Antagonisten und zusätzlich der Peptide Teverelix und D-Phe6-GnRH sowie von verkürzten Fragmenten des Cetrorelix wurde untersucht. Ein Strukturmodell für die Beschreibung der Aggregation der Dekapeptide wurde erarbeitet. Der Aufbau eines Rechenclusters durch das Einbinden der Computer am Lehrstuhl in ein Linux-System zur Verteilung von Rechenprozessen über das Netzwerk ermöglichte die Bereitstellung der notwendigen Leistung zur Realisierung der Berechnungen. Es wurden Werkzeuge zur Modellierung der solvatisierten Aggregate von Peptiden ohne eindeutige Vorzugsstruktur programmiert und in ein Docking-System für beliebige Moleküle eingebunden. Verwendet wurde das Kraftfeld MMFF94 mit einer Erweiterung durch ein Verfahren zur dynamischen Berechnung von Partialladungen in Molekülstrukturen. Solvatisierte Aggregate der Dekapeptide und von bekannten amyloidbildenden Strukturen wurden modelliert (Docking). Berechnet wurden als aggregierend beschriebene Sequenzen und entsprechende Vergleichsstrukturen des Calcitonins, des Insel-Amyloid-Polypeptides, des beta2-Mikroglobulins, des Amyloid-beta-Proteins, des Lactoferrins und weitere Modellpeptide. Die wesentlichen Wechselwirkungen während der Aggregation konnten schließlich anhand von Dynamik-Simulationen der faltblattartigen Dimere des Cetrorelix und Ozarelix beschrieben werden. So wurden die Prozesse der hydrophoben Assoziation und Stabilisierung durch Wasserstoffbrücken von Peptiden veranschaulicht und auf molekularer Ebene erfolgreich analysiert. Die Visualisierung der erhaltenen Modellierungsergebnisse erfolgt durch die Darstellung der Strukturen und Dynamik-Simulationen als interaktive 3D-Modelle in einem für diese Arbeit aufgebauten Internetauftritt<br>This work discusses the analysis of the aggregation properties of the gonadotropin releasing hormone antagonists Cetrorelix, Teverelix, Ozarelix and of small amyloid forming model peptides by analytical fluorescence spectroscopy and molecular modelling. A high performance linux compute cluster was developed for calculation of molecular structures. Solvated aggregate clusters of peptides without defined secondary structure were modelled by molecular mechanics methods (forcefield mmff94) in combination with an advanced charge equilibration and docking technique. Molecular dynamics of solvated peptide dimers were implemented and the role of hydrophic association and hydrogen bond formation in hydrophobic peptide aggregates was explained. Finally, an aggregation model for the directed association of hydrophobic peptides is presented. The modelling results, 3d structures and dynamic simulations are visualized in an interactive web material

Chan, Chung Yin.<br>Thesis (M.Phil.)--Chinese University of Hong Kong, 2011.<br>Includes bibliographical references (leaves 77-80).<br>Abstracts in English and Chinese.<br>Table of Contents --- p.i<br>Acknowledgements --- p.iii<br>Abbreviations --- p.V<br>Abstract --- p.vi<br>Chapter Chapter 1 - --- Introduction --- p.1<br>Chapter 1.1 --- Definition of Aromatic Bond Activation --- p.1<br>Chapter 1.2 --- History of Carbon-Fluorine Bond Activation --- p.1<br>Chapter 2.2.1 --- Examples of Aromatic Carbon-Fluorine Bond Activation in 1970s --- p.1<br>Chapter 2.2.2 --- Examples of Aromatic Carbon-Fluorine Bond Activation in 1980s --- p.2<br>Chapter 2.2.3 --- Examples of Aromatic Carbon-Fluorine Bond Activation in 1990s --- p.3<br>Chapter 2.2.4 --- Examples of Aromatic Carbon-Fluorine Bond Activation in 2000s --- p.6<br>Chapter 1.3 --- Difficulties and Challenges in Aromatic Bond Activation Applications of Aromatic Carbon Fluorine Bond Activation --- p.6<br>Chapter 2.2.1 --- Thermodynamic Estimations --- p.7<br>Chapter 2.2.2 --- Competitive Aromatic Bond Activation --- p.9<br>Chapter 1.3.2.1 --- Competitive Aromatic Carbon-Hydrogen and Carbon-Halogen Bond Activation --- p.10<br>Chapter 1.3.2.2 --- Competitive Aromatic Carbon-Hydrogen and Carbon-Fluorine Bond Activation --- p.15<br>Chapter 1.4 --- Mechanistic Investigations of Aromatic CFA --- p.17<br>Chapter 2.2.1 --- Oxidative Addition --- p.17<br>Chapter 2.2.2 --- Nucleophilic Aromatic Substitution --- p.18<br>Chapter 2.2.3 --- Fluorine Atom Abstraction --- p.19<br>Chapter 2.2.4 --- "1,2-Addition" --- p.19<br>Chapter 1.5 --- Mechanistic Investigations of Aromatic Carbon-Hydrogen Bond Activation --- p.20<br>Chapter 2.2.1 --- Oxidative Addition --- p.20<br>Chapter 2.2.2 --- Electrophilic Aromatic Substitution --- p.21<br>Chapter 2.2.3 --- "1,2-Addition" --- p.21<br>Chapter 1.6 --- Applications of Aromatic Carbon-Fluorine Bond Activation --- p.22<br>Chapter 1.7 --- Applications of Aromatic Carbon-Hydrogen Bond Activation --- p.23<br>Chapter 1.8 --- Structural Features of Iridium Porphyrins --- p.23<br>Chapter 1.9 --- Obj ectives of the Work --- p.25<br>Chapter Chapter 2 - --- Competitive Aromatic Carbon Fluorine and Carbon Hydrogen Bond Activation by Iridium(III) Porphyrins --- p.26<br>Chapter 2.1 --- C-F Activation of Fluorobenzene by Rhodium(III) Porphyrins --- p.26<br>Chapter 2.2 --- Preparation of Starting Materials --- p.26<br>Chapter 2.2.1 --- Preparation of Tetratolylporphyrin --- p.26<br>Chapter 2.2.2 --- Preparation of Iridium(III) Porphyrin Carbonyl Chloride --- p.27<br>Chapter 2.3 --- Base Effect of Carbon-Fluorine Bond Activation --- p.27<br>Chapter 2.4 --- Solvent Effect of Carbon-Fluorine Bond Activation --- p.30<br>Chapter 2.5 --- Temperature Effect --- p.31<br>Chapter 2.6 --- Concentration Effect of Carbon-Fluorine Bond Activation --- p.33<br>Chapter 2.7 --- Activations of Fluorobenzenes --- p.33<br>Chapter 2.8 --- Electronic Effect --- p.36<br>Chapter 2.9 --- Mechanistic Studies --- p.38<br>Chapter 2.9.1 --- Activation of Fluorobenzene --- p.38<br>Chapter 2.9.2 --- Reaction between Ir(ttp)H and Fluorobenzene --- p.40<br>Chapter 2.9.3 --- Reaction between Ir2(ttp)2 and Fluorobenzene --- p.41<br>Chapter 2.9.4 --- "Reaction between Ir(ttp)""K+ and Fluorobenzene" --- p.42<br>Chapter 2.9.5 --- Reaction between Ir(ttp)Me and Fluorobenzene --- p.44<br>Chapter 2.10 --- Proposed Mechanism for CFA --- p.45<br>Chapter 2.11 --- Proposed Mechanism for CHA --- p.47<br>Chapter 2.12 --- Kinetic and Thermodynamic CFA and CHA Products --- p.47<br>Chapter 2.13 --- Summary --- p.48<br>Chapter Chapter 3 - --- Experimental Section --- p.49<br>Reference --- p.77<br>Chapter Appendix I - --- Spectra --- p.81

The selective synthesis of symmetrical organic sulfide using industrial waste gas hydrogen sulfide (H2S) is a bit challenging. The present kinetic investigation is based on H2S gas released from refineries is chemisorbed in an industrially important alkanolamine,N-methyldiethanolamine (MDEA) followed by a biphasic reaction between the two immiscible reactants H2S–laden MDEA and p-chlorobenzyl chloride in solvent free condition to yield bis(p-chlorobenzyl sulphide) (BPCBS) using an ionic liquid as a phase transfer catalyst. Phosphonium-based ionic liquid was found to be an efficient biphasic catalyst as a significant amount of desired product was obtained in just 5 min of reaction. The selectivity of the desired product BPCBS was achieved as 100% at the optimized level of various process parameters. A Suitable mechanism has been proposed to explain the course of the reaction. A kinetic model was developed and validated successfully. The solvent-free condition is a ―green‖ approach which eliminates the use of harmful solvents. Another work was also carried for the determination of the numerical value of distribution coefficient and dissociation constant for Tetrabutylammonium bromide (TBAB) and Trihexyltetradecyl phosphonium chloride (ionic liquid). The value of distribution coefficient is determined by the UV-spectrometry method for four systems viz. toluene-water system, benzene-water system, chlorobenzene-water system and p-CBC-water. The estimated distribution coefficient was highest for benzene-water for both the catalyst studied. The value of dissociation constant was investigated to be same irrespective of the change in concentration of the catalyst. In the last study, an easy-preparation procedure was adopted for the synthesis of Multi-site phase transfer catalyst. The dual-site MPTC viz. 1,4- bis(triethylmethylammonium)benzene dichloride (DC-X) and 4,4‘-bis- (Triethylmethylammonium)-1, 1‘-biphenyl Dichloride (4, 4‘-B(TEMA)-1,1‘-BP DC). A polymer-bound N-ethyl-N-di-isopropyl ammonium chloride phase transfer catalyst was also synthesized and characterized. The formation of all the catalysts was evident from the FT-IR, NMR and elemental analysis. The catalytic activity of one of the prepared MPTC viz. bis- Quaternary Ammonium Salts 4,4‘-bis (triethylmethylammonium)-1,1‘-biphenyl dichloride (4,4‘- B(TEMA)-1,1‘-BP DC) was investigated by utilizing it for the sulfidation of different type of alkyl halides, which results in various types of thioethers.

This present investigation is based on the idea of using waste sulfur compound i.e. Hydrogen Sulfide (H2S) which is unutilized byproduct of industries like petroleum and natural gas processing industries. This proposed work comprises of two stages: firstly, conventional absorption of H2S in the absorbent alkanolamines like methyldiethanolamine (MDEA) which is selective towards hydrogen sulfide. This H2S-rich MDEA solution has been proposed to act as a sulfiding agent for aromatic halides to synthesize aromatic thioether which is a fine chemical used in photographic emulsions, high pressure lubricants and additive as anti-wear in motor oil and has application in various anticorrosive formulations. The objective is to synthesize the aromatic thioether like Bis-(p-chlorobenzyl) Sulfide) using reactant aromatic halides like (p-chlorobenzyl chloride) and H2S rich aqueous alkanolamines (e.g. MEA, MDEA etc.). For this double phasic reaction was carried out in presence or absence of solvent like toluene as well as insoluble phase transfer catalyst are being used. This present work is carried out using tributylmethylammonium chloride-polymer bound, tributylmethylphosphonium chloride-polymer bound and Amberlite IR-400 as the insoluble catalysts which were further reused for betterment of the economy of the project. So the study was carried out in three phases. The initial experiments shows encouraging results with 100% conversion of reactant p-chlorobenzylchloride in the solvent toluene, 100% selectivity of the desired product Bis-(p- chlorobenzyl) sulfide) and the catalyst was reused up to 3 times. A generalized empirical kinetic model was developed and successfully validated against the experimental results. In the second phase of study, Response surface methodology accompanied with Central composite design was used for the study of the reaction kinetics, model development and the optimization of the reaction conditions. In the third phase study, solvent free synthesis of Bis-(p-chlorobenzyl) Sulfide) was carried out. This whole investigation is oriented towards a green technology for utilizing toxic H2S under waste management approach.

Eight ABC heterotrimers whose self-assembly are directed through electrostatic interactions were studied here. Oppositely charged pairs of amino acids, with varying side chain length, were assessed for their ability to stabilize a triple helix. Aspartate-lysine was found to result in the most thermally stable helix followed by lysine-glutamate, ornithine-aspartate and finally ornithine-glutamate. When the sequence position of these charged amino acids was reversed from what is normally observed in nature, triple helix stability and compositional purity was significantly reduced. The effect of salt on triple helix stability was explored and it was observed that increased salt concentration reduces the thermal stability of heterotrimers by an average of 5&deg;C, but does not disrupt helix assembly. It was also found that positively charged homotrimers can be stabilized in the presence of phosphate anions. Raman and Surface-enhanced Raman spectroscopies (SERS) are potentially important tools in the characterization of biomolecules such as proteins and DNA. In this work, SERS spectra of three cysteine containing aromatic peptides: tryptophan-cysteine, tyrosine-cysteine, and phenylalanine-cysteine, bound to Au nanoshell substrates, were obtained and compared to their respective normal Raman spectra. While the full widths at half maximum of the SERS peaks are significantly broadened (up to 70%), no significant spectral shifts (&lt;6 cm-1) of the major Stokes modes were observed between the two modalities. It is shown that the Raman and SERS spectra of penetratin, a cell-penetrating peptide, can be evaluated quite reliably from the spectra of its constituent aromatic amino acids except in the -CH2- bending and amide I and III regions where the spectral intensities are critically dependent on the chain length and/or protein conformations. From this study we conclude that with aromatic amino acid residues provide the overwhelmingly dominant features in the Raman and SERS spectra of peptides and proteins, and that the Raman modes of these three small constructed peptides can apply directly to the assignment of Raman and SERS features in the spectra of larger peptides and proteins.

Lee, Man Ho.<br>Thesis submitted in: October 2008.<br>Thesis (M.Phil.)--Chinese University of Hong Kong, 2009.<br>Includes bibliographical references (leaves 78-83).<br>Abstracts in English and Chinese.<br>Table of Contents --- p.ii<br>Acknowledgements --- p.iv<br>Abbreviations --- p.v<br>Abstract --- p.vi<br>Chapter Chapter 1 --- Introduction<br>Chapter 1.1 --- Definition of Aromatic Bond Activation --- p.1<br>Chapter 1.2 --- Application of Aromatic Carbon Fluorine Bond Activation --- p.1<br>Chapter 1.3 --- Mechanistic Schemes Involved in Aromatic Bond Activation --- p.2<br>Chapter 1.4 --- Difficulties in Aromatic Bond Activation --- p.7<br>Chapter 1.5 --- Competitive Bond Activations --- p.20<br>Chapter 1.6 --- Structural Features of Rhodium Porphyrins --- p.27<br>Chapter 1.7 --- Objective of the Work --- p.28<br>Chapter Chapter 2 --- Competitive C-F and C-H Activation of Fluorobenzenes by Rhodium(III) Porphyrins<br>Chapter 2.1 --- C-F Activation of Fluorobenzene by Rhodium(III) Porphyrins --- p.29<br>Chapter 2.2 --- Preparation of Starting Materials --- p.29<br>Chapter 2.3 --- Base Effect of CFA --- p.30<br>Chapter 2.4 --- Solvent Effect of CFA --- p.32<br>Chapter 2.5 --- Temperature Effect of CFA Reaction --- p.34<br>Chapter 2.6 --- Activations of Fluorobenzene --- p.35<br>Chapter 2.7 --- Electronic Effect of Carbon-Fluorine Bond Activations --- p.38<br>Chapter 2.8 --- Preliminary Mechanistic Studies --- p.39<br>Chapter 2.9 --- Proposed C-F Activation Mechanism --- p.44<br>Chapter 2.10 --- Proposed C-H Activation Mechanism --- p.48<br>Chapter 2.11 --- Summary --- p.51<br>Chapter Chapter 3 --- Experimental Section --- p.56<br>References --- p.78<br>Table of Content of Appendix --- p.83<br>Appendix I Crystal Data and Processing Parameters --- p.85<br>Appendix II Spectra --- p.91

by Chiu Peng Fai.<br>Thesis (M.Phil.)--Chinese University of Hong Kong, 2006.<br>Includes bibliographical references (leaves 82-87).<br>Abstracts in English and Chinese.<br>Table of Contents --- p.i<br>Acknowledgements --- p.iv<br>Abbreviations --- p.v<br>Abstract --- p.vi<br>Chapter Chapter 1 --- Introduction<br>Chapter 1.1 --- Definition of Carbon Hydrogen Bond Activation (CHA) by Transition Metal Comple --- p.1 x<br>Chapter 1.2 --- The Importance of Alkane CHA and its Potential Use --- p.1<br>Chapter 1.3 --- Difficulties in Alkane CHA --- p.3<br>Chapter 1.4 --- The Use of Transition Metal Complexes in CHA Reactions --- p.4<br>Chapter 1.5 --- Classification of CHA Reactions --- p.6<br>Chapter 1.6 --- The Importance of Toluene and Benzene CHA --- p.11<br>Chapter 1.7 --- Difficulties and Challenges in CHA of Toluene --- p.11<br>Chapter 1.8 --- Selectivity Control and Rate Promotion --- p.12<br>Chapter 1.9 --- Structural Features of Rhodium Porphyrins --- p.17<br>Chapter 1.10 --- CHA by Rhodium Porphyrins --- p.19<br>Chapter 1.11 --- Objective of Work --- p.21<br>Chapter Chapter 2 --- CHA Reactions of Toluenes by Rhodium Porphyrin Chlorides<br>Chapter 2.1 --- Synthesis of Rhodium Porphyrin Chlorides --- p.22<br>Chapter 2.2 --- Temperature Effects of CHA in Toluene --- p.22<br>Chapter 2.3 --- Inter and Intra Molecular Exchange of Alkyl Rhodium Porphyrin Complexes --- p.24<br>Chapter 2.4 --- Electronic Effect of Rhodium Porphyrin Chlorides --- p.24<br>Chapter 2.5 --- Electronic Effect of Toluene Towards CHA --- p.25<br>Chapter 2.6 --- X-Ray Data --- p.26<br>Chapter 2.7 --- Mechanistic Studies --- p.30<br>Chapter 2.8 --- Ligand and Base Effects --- p.32<br>Chapter 2.9 --- Optimization of Reaction Conditions --- p.35<br>Chapter 2.10 --- Electronic Effect of Toluenes --- p.36<br>Chapter 2.11 --- Concentraction Effects of Toluenes (Reactions in Benzene) --- p.38<br>Chapter 2.12 --- Porphyrin Effects in CHA of Toluene --- p.39<br>Chapter 2.13 --- Mechanistic Studies --- p.40<br>Chapter 2.14 --- Conclusion --- p.42<br>Chapter 2.15 --- Reaction between Rh(ttp)Me and Toluenes --- p.42<br>Chapter 2.16 --- Selective Benzylic CHA --- p.42<br>Chapter 2.17 --- Isotope Effect --- p.44<br>Chapter 2.18 --- Discussion --- p.44<br>Chapter 2.19 --- Exploratory Studies of Other Base-Promoted Reactions --- p.45<br>Chapter 2.20 --- Benzylic CHA and Aromatic Carbon Halogen Bond Activation (CXA) Reactions --- p.45<br>Chapter 2.21 --- Base-Enhanced Aromatic CXA --- p.48<br>Chapter 2.22 --- X-Ray Data --- p.49<br>Chapter 2.23 --- Base-Enhanced Benzylic Carbon Carbon Bond Activation (CCA) Reactions --- p.51<br>Chapter 2.24 --- Summary --- p.52<br>Chapter Chapter 3 --- Experimental Sections --- p.53<br>References --- p.82<br>Appendix I Crystal Data and Processing Parameters --- p.88<br>Appendix II List of Spectra --- p.123<br>Spectra --- p.125

Solvent effects play diverse roles in myriads of chemical, physical and biological processes. The solvent interacts with the solute by: i) non-specific (Coulombic, van der Waals interactions) and ii) specific interactions (hydrogen bonding, etc.). These interactions are responsible for solvation of the solute and are collectively termed as “solvent polarity”. Differential solvation of ground and excited electronic states is manifested in the absorption spectrum as a change in the band position, intensity or shape, which is termed as “solvatochromism”. Intermolecular hydrogen bonding (IHB) is a kind of specific solute-solvent interaction, which plays a key role in molecular or supramolecular photochemistry, as well as in photobiology. Solvation and its influence on various physico-chemical and biological processes can be understood by i) top-down; and ii) bottom-up approaches. In the top-down approach, the macroscopic properties like dielectric constant, refractive index are used to understand the microscopic solvation. This approach fails when specific interactions like hydrogen bonding interactions come into play, and furthermore it can reproduce only the macroscopic polarization of the solvent but fails miserably at the cybotactic region of solvation. With the recent advancements in the computational field, the molecular level description of solvation has been within reach for chemical physicists and experimentalists to corroborate their experimental results and in turn to visualize processes of fundamental or technologically relevant problems. The energy levels of the nπ* and ππ* singlet and triplet excited states of aromatic ketones are close-lying and therefore their energy levels can be altered by the substituents. The solvent polarity can be used as a surrogate to tune their energy levels. In certain cases, the lowest triplet or singlet excited states can switch their electronic character with increasing solvent polarity known as “electronic state switching” and thus modulate their photochemical or photophysical properties. Therefore, aromatic ketones were used as solvatochromic probes in this work. Comprehensive analyses of the solvent effects on xanthone (XT), 9,10-phenanthrenequinone (PQ) and benzophenone (Bzp) were carried out using steady-state and nanosecond time-resolved absorption, and resonance Raman spectroscopy in conjunction with ad hoc and classical-molecular dynamics and simulations generated supermolecule-continuum solvent model quantum mechanical calculations to corroborate the experimental outcomes and in turn to visualize the solvation process at the molecular level. The present thesis is divided into eight chapters and the summary of each chapter is described below: Chapter 1 provides a brief literature review of solvation effects and their influence on various physico-chemical and biological processes. Furthermore, the importance of understanding solvation at the molecular level and key concepts are discussed, which forms the heart of this thesis. Chapter 2 discusses the experimental and computational approaches used to study the solvation processes at the molecular level. A detailed explanation of spectroscopic techniques like resonance Raman (RR) and nanosecond-time resolved resonance Raman (ns-TR3) spectroscopy and their experimental and theoretical aspects are discussed, followed by a discussion on the fundamental concepts of computational methods like ab initio calculations density functional theory (DFT), and classical molecular dynamics and simulations (c-MDS) utilized in this study. Chapter 3 focuses on microscopic understanding of solvatochromic shifts observed for 9,10-phenanthrenequinone in protic solvents using UV-Vis and RR spectroscopy in conjunction with an ad hoc explicit solvation model and time-dependent density functional theory (TDDFT) calculations. The hypsochromic shift and bathochromic shift of the singlet nπ* and ππ* electronic transitions in protic solvents are due to hydrogen bond weakening and strengthening in the excited state for the corresponding electronic transitions, respectively as indicated by TD-DFT calculations and Kamlet-Taft linear solvation energy relationships. The hydrogen bond strengthening in the singlet ππ* excited state is further confirmed by Raman excitation profile (REP) analysis of PQ in different solvents. Furthermore, with increasing solvent polarity the two lowest singlet excited states undergo different hydrogen bonding mechanisms, leading to a decreasing energy gap between them. Therefore, hyperchromism of the nπ* transition has been hypothesized to be due to an increasing vibronic coupling between the lowest singlet nπ* and ππ* excited states. In Chapter 4, a real time observation of the thermal equilibrium between the lowest triplet excited states of PQ in acetonitrile solvent was carried out using ns-TR3 spectroscopy and this can explain its high reactivity towards H-atom abstraction, despite the fact that the lowest triplet excited state has ππ* character. Furthermore, extending the concept of hydrogen bonding mechanisms of the lowest singlet to the triplet excited states, the different hydrogen bonding mechanisms exhibited by them can lead to alteration of the intersystem crossing mechanisms in PQ. Chapter 5 highlights the very different role of intermolecular hydrogen bonding in the reduced reactivity of the xanthone (XT) triplet towards H-atom abstraction in protic solvents. The different hydrogen bonding mechanisms exhibited by the two lowest triplet excited states in protic solvents are derived from an ad hoc explicit solvation model, TD-DFT calculations and ns-time resolved absorption (ns-TRA): they separate them further in energy and thereby the nearest T2(nπ*) triplet state to the T1(ππ*) excited state plays an insignificant role in the reactivity towards H-atom abstraction, in contrast to the PQ triplet discussed in Chapter 4. Chapter 6 discusses the structure of XT triplet states using TR3 spectroscopy in combination with TD-DFT studies. The TR3 spectrum of the XT in acetonitrile identified a vibronic coupling mode responsible for the reactivity of XT towards H-atom abstraction, despite the fact that the lowest triplet excited state (T1) has ππ* character. This vibronic active mode is absent in the TR3 spectra of XT in protic solvents (methanol and ethanol). Furthermore, the REP analysis suggests that the nanosecond triplet-triplet absorption spectrum of XT in acetonitrile involves two different species, while in methanol it involves only one species. This observation is in agreement with the previous chapter (Chapter 5) which proposes a different hydrogen bonding mechanisms for the two lowest triplet excited states and their influence on the reduced reactivity towards H-atom abstraction. Chapters 3-6 emphasize the need for a proper solvation model at the molecular level to describe the various photophysical and photochemical processes of aromatic ketones. Therefore, Chapter 7 includes discussions on the bottom-up solvation methodology applied to benzophenone (Bzp) to understand its vibrational and electronic solvatochromic behaviour at the molecular level. Raman and UV-Vis spectroscopic techniques were used in conjunction with a c-MDS-generated supermolecule continuum solvation model DFT calculation to corroborate and to visualize the experimental outcome. The carbonyl stretching frequency of Bzp in protic solvents has two bands, corresponding to free carbonyl and hydrogen bonded carbonyl. Despite the fact that the macroscopic polarity of acetonitrile and methanol solvents are similar, the free carbonyl stretching of Bzp in methanol solvent was blue-shifted by 4 cm-1 with respect to the carbonyl stretching in acetonitrile solvent. The Gutmann’s acceptor number plot for carbonyl stretching frequencies indicates that the free carbonyl group is neighboured by a hydrophobic environment. The c-MDS-generated supermolecule-continuum solvation model DFT calculations suggest that the extended hydrogen bonding network of methanol solvent is responsible for the hydrophobic solvation around the free carbonyl. Furthermore, a linear correlation was obtained for the vibrational and electronic solvatochromism of the carbonyl frequency and energy of the singlet nπ* transition, respectively, which indicates that a variation in excitation wavelength for the singlet nπ* transition can arise from different solvation states. This can have implications for ultrafast processes associated with electron transfer, charge-transfer and also the photophysical aspects of excited states.Finally, Chapter 8 contains overall conclusions of the thesis and future directions for the present research area.

Solvent effects play diverse roles in myriads of chemical, physical and biological processes. The solvent interacts with the solute by: i) non-specific (Coulombic, van der Waals interactions) and ii) specific interactions (hydrogen bonding, etc.). These interactions are responsible for solvation of the solute and are collectively termed as “solvent polarity”. Differential solvation of ground and excited electronic states is manifested in the absorption spectrum as a change in the band position, intensity or shape, which is termed as “solvatochromism”. Intermolecular hydrogen bonding (IHB) is a kind of specific solute-solvent interaction, which plays a key role in molecular or supramolecular photochemistry, as well as in photobiology. Solvation and its influence on various physico-chemical and biological processes can be understood by i) top-down; and ii) bottom-up approaches. In the top-down approach, the macroscopic properties like dielectric constant, refractive index are used to understand the microscopic solvation. This approach fails when specific interactions like hydrogen bonding interactions come into play, and furthermore it can reproduce only the macroscopic polarization of the solvent but fails miserably at the cybotactic region of solvation. With the recent advancements in the computational field, the molecular level description of solvation has been within reach for chemical physicists and experimentalists to corroborate their experimental results and in turn to visualize processes of fundamental or technologically relevant problems. The energy levels of the nπ* and ππ* singlet and triplet excited states of aromatic ketones are close-lying and therefore their energy levels can be altered by the substituents. The solvent polarity can be used as a surrogate to tune their energy levels. In certain cases, the lowest triplet or singlet excited states can switch their electronic character with increasing solvent polarity known as “electronic state switching” and thus modulate their photochemical or photophysical properties. Therefore, aromatic ketones were used as solvatochromic probes in this work. Comprehensive analyses of the solvent effects on xanthone (XT), 9,10-phenanthrenequinone (PQ) and benzophenone (Bzp) were carried out using steady-state and nanosecond time-resolved absorption, and resonance Raman spectroscopy in conjunction with ad hoc and classical-molecular dynamics and simulations generated supermolecule-continuum solvent model quantum mechanical calculations to corroborate the experimental outcomes and in turn to visualize the solvation process at the molecular level. The present thesis is divided into eight chapters and the summary of each chapter is described below: Chapter 1 provides a brief literature review of solvation effects and their influence on various physico-chemical and biological processes. Furthermore, the importance of understanding solvation at the molecular level and key concepts are discussed, which forms the heart of this thesis. Chapter 2 discusses the experimental and computational approaches used to study the solvation processes at the molecular level. A detailed explanation of spectroscopic techniques like resonance Raman (RR) and nanosecond-time resolved resonance Raman (ns-TR3) spectroscopy and their experimental and theoretical aspects are discussed, followed by a discussion on the fundamental concepts of computational methods like ab initio calculations density functional theory (DFT), and classical molecular dynamics and simulations (c-MDS) utilized in this study. Chapter 3 focuses on microscopic understanding of solvatochromic shifts observed for 9,10-phenanthrenequinone in protic solvents using UV-Vis and RR spectroscopy in conjunction with an ad hoc explicit solvation model and time-dependent density functional theory (TDDFT) calculations. The hypsochromic shift and bathochromic shift of the singlet nπ* and ππ* electronic transitions in protic solvents are due to hydrogen bond weakening and strengthening in the excited state for the corresponding electronic transitions, respectively as indicated by TD-DFT calculations and Kamlet-Taft linear solvation energy relationships. The hydrogen bond strengthening in the singlet ππ* excited state is further confirmed by Raman excitation profile (REP) analysis of PQ in different solvents. Furthermore, with increasing solvent polarity the two lowest singlet excited states undergo different hydrogen bonding mechanisms, leading to a decreasing energy gap between them. Therefore, hyperchromism of the nπ* transition has been hypothesized to be due to an increasing vibronic coupling between the lowest singlet nπ* and ππ* excited states. In Chapter 4, a real time observation of the thermal equilibrium between the lowest triplet excited states of PQ in acetonitrile solvent was carried out using ns-TR3 spectroscopy and this can explain its high reactivity towards H-atom abstraction, despite the fact that the lowest triplet excited state has ππ* character. Furthermore, extending the concept of hydrogen bonding mechanisms of the lowest singlet to the triplet excited states, the different hydrogen bonding mechanisms exhibited by them can lead to alteration of the intersystem crossing mechanisms in PQ. Chapter 5 highlights the very different role of intermolecular hydrogen bonding in the reduced reactivity of the xanthone (XT) triplet towards H-atom abstraction in protic solvents. The different hydrogen bonding mechanisms exhibited by the two lowest triplet excited states in protic solvents are derived from an ad hoc explicit solvation model, TD-DFT calculations and ns-time resolved absorption (ns-TRA): they separate them further in energy and thereby the nearest T2(nπ*) triplet state to the T1(ππ*) excited state plays an insignificant role in the reactivity towards H-atom abstraction, in contrast to the PQ triplet discussed in Chapter 4. Chapter 6 discusses the structure of XT triplet states using TR3 spectroscopy in combination with TD-DFT studies. The TR3 spectrum of the XT in acetonitrile identified a vibronic coupling mode responsible for the reactivity of XT towards H-atom abstraction, despite the fact that the lowest triplet excited state (T1) has ππ* character. This vibronic active mode is absent in the TR3 spectra of XT in protic solvents (methanol and ethanol). Furthermore, the REP analysis suggests that the nanosecond triplet-triplet absorption spectrum of XT in acetonitrile involves two different species, while in methanol it involves only one species. This observation is in agreement with the previous chapter (Chapter 5) which proposes a different hydrogen bonding mechanisms for the two lowest triplet excited states and their influence on the reduced reactivity towards H-atom abstraction. Chapters 3-6 emphasize the need for a proper solvation model at the molecular level to describe the various photophysical and photochemical processes of aromatic ketones. Therefore, Chapter 7 includes discussions on the bottom-up solvation methodology applied to benzophenone (Bzp) to understand its vibrational and electronic solvatochromic behaviour at the molecular level. Raman and UV-Vis spectroscopic techniques were used in conjunction with a c-MDS-generated supermolecule continuum solvation model DFT calculation to corroborate and to visualize the experimental outcome. The carbonyl stretching frequency of Bzp in protic solvents has two bands, corresponding to free carbonyl and hydrogen bonded carbonyl. Despite the fact that the macroscopic polarity of acetonitrile and methanol solvents are similar, the free carbonyl stretching of Bzp in methanol solvent was blue-shifted by 4 cm-1 with respect to the carbonyl stretching in acetonitrile solvent. The Gutmann’s acceptor number plot for carbonyl stretching frequencies indicates that the free carbonyl group is neighboured by a hydrophobic environment. The c-MDS-generated supermolecule-continuum solvation model DFT calculations suggest that the extended hydrogen bonding network of methanol solvent is responsible for the hydrophobic solvation around the free carbonyl. Furthermore, a linear correlation was obtained for the vibrational and electronic solvatochromism of the carbonyl frequency and energy of the singlet nπ* transition, respectively, which indicates that a variation in excitation wavelength for the singlet nπ* transition can arise from different solvation states. This can have implications for ultrafast processes associated with electron transfer, charge-transfer and also the photophysical aspects of excited states.Finally, Chapter 8 contains overall conclusions of the thesis and future directions for the present research area.

Department of Chemistry<br>PhD (Chemistry)<br>This thesis is concerned with the computational study of naphthylisoquinoline alkaloids having antimalarial properties. The study was considered interesting because of the importance of gathering information on antimalarial molecules and because these molecules had not yet been studied computationally. The alkaloids considered in this study had been isolated from tropical lianas belonging to the Dioncophyllaceae and Ancistrodaceae families. They comprise alkaloids with both monomeric and dimeric structures. The monomeric structures consist of one unit and the dimeric ones of two units, with each unit containing a naphthalene moiety and an isoquinoline moiety. 33 monomeric molecules were studied, which represent a large portion of all the monomeric naphthylisoquinoline alkaloids isolated so far. Two dimeric molecules with antimalarial activity were investigated, namely, jozimine A2 and mbandakamine A. A third dimeric molecule, with a structure close to that of jozimine A2 but different activity (michellamine A, anti-HIV) was also calculated for comparison purposes. This work utilised electronic structures methods and involved the conformational study of all the molecules selected to identify the stabilising factors in vacuo and in solution. Two levels of theory (HF/ 6-31G (d,p) and DFT/B3LYP/ 6-31+G(d,p)) were utilised to compare their performance for compounds of this type, also in view of a future study extending to other compounds of the same class. The molecules were firstly studied in vacuo and secondly in three different solvents – chloroform, acetonitrile and water – characterized by different polarities and different H-bonding abilities. Quantum chemical calculations in solution were carried out using the Polarisable Continuum Model (PCM). The main stabilizing factors are the presence and types of intramolecular hydrogen bonds (IHBs), which are the dominant factors, and also the mutual orientation of the moieties. The possible IHBs comprise OH⋯O (or OH⋯N and NH⋯O for mbandakamine A) and other H-bond types interactions such as OH⋯ and CH⋯O (or CH⋯O and CH⋯N for mbandakamine A). The moieties prefer to be perpendicular one to another, which is a common tendency of aromatic vii systems. In monomeric structures, there may be only one OH⋯O and possibly also one of each of the other two types of IHBs interactions. In dimeric structures, there may be up to four (five in mbandakamine A) OH⋯O IHBs simultaneously and also other H-bond type interactions. The results provide a comprehensive picture of the molecular properties of these compounds, such as conformational preferences, dipole moments, HOMO-LUMO energy gaps, harmonic vibrational frequencies, solvent effect and influence of the solvent on molecular properties which respond to polarisation by the solvent. Altogether, these results may contribute to a better understanding of their biological activity and to the design of molecular structures with enhanced biological activity. This is the reason of focusing the efforts on the investigation of chemical and physical properties of these alkaloids molecules.<br>NRF

博士<br>國立交通大學<br>材料科學與工程學系奈米科技碩博士班<br>107<br>In this dissertation, we have attempted to develop a series of single and two component hydrogels based on ultrashort aromatic peptide amphiphiles and evaluate their applications. This thesis is composed of 8 chapters, the first chapter deals with the general introduction. The second chapter describes the materials and methods that are used for synthesizing and characterizing the hydrogels. Chapter-3 and 4 describe design synthesis and hydrogelation of a series of peptide amphiphiles capped with naphthalene diimide (NDI) and pyrene chromophores. In chapter-3 NDI conjugated single amino acid and pyrene butyric acid (Py), were used to promote the formation of the supramolecular nanofibers and Charge transfer (CT) hydrogels. Amino acid sequences were found to have significant influence on the structural morphology and stability of the hydrogels. In chaper-4, the supramolecular hydrogelation of NDI-Py mixed component systems were described. Such system provided opportunities to construct new type of supramolecular hydrogels through aromatic complementary CT iv interactions. In addition NDI and Pyrene based single amino acids with a match pair and mismatch pair giving a stable hydrogel of nanofibrous morphology with the average diameter of about 6-9 nm as evidenced by TEM analysis. In addition, this novel NDI-Py mixed component system exhibited good biocompatibility towards PC3 cells. Overall, since hydrogels based on CT-mediated two-component assemblies are very rare, our newly discovered NDI-Py hydrogels provide the chemical insights into the design of CT-induced hydrogelator and might facilitate various applications in biomedical engineering. Fifth part we describe the blends of oppositely charged Py-gelators (Py-Glu and Py-Lys) resultant in formation of fluorescent physiological hydrogels with nanofibers architecture as evident from various microscopic and spectroscopic techniques. The formation of hydrogels display unique helical fibers morphology which clearly shows the significance of additional electrostatic interactions in self-assembly. Overall, this work illustrates the importance of two-component supramolecular co-assembled fluorescent hydrogels and their structure–morphology relationship, improved mechanical properties and biocompatibility and thus provides a new insight into the design of self-assembled nanomaterials. In sixth part of the study, a new system of a NSAID drug (ketorolac) conjugate with peptides were studied. In general NSAID-capped supramolecular hydrogels are clinically useful as topical agents for treating inflammation and relieving pain and may have potential applications in sustained drug delivery. The Ketorolac based tripeptides illustrates a new approach to improve the COX-2/COX-1 selectivity ratio of Ket drug through controlling the stereochemistry of the chemical structures, which may have a wide range of future clinical applications in treating chronic inflammation.A series of anti-inflammatory supramolecular hydrogelators made of ketorolac/tripeptide conjugates that form supramolecular hydrogels at physiological pH. Our findings indicate ketorolac-capped tripeptide Ket-Gly-D-Phe-D-Phe shows reversal of COX selectivity which is a potential candidate for topical and therapeutic applications. v In chapter-7 the synthesis and self-assemblying of a series of 4-piperidine 1, 8-naphthalene diimide based dipeptides were described.Most interesting discovery is that the self-assembly was greatly influenced by both pH and concentration for all hydrogelators. The self-assembly of PPNI-capped dipeptides, which is proceeded via π–π interactions and hydrogen bonding under aqueous conditions into nano-tubular structures were explained based on various spectroscopic and microscopic techniques. In particular, PPNI-FS having one hydroxyl group, which is self-assemble into well-defined supramolecular physiological hydrogel with a nano-tubular morphology in various conditions and good biocompatible material. Overall, this study illustrates the importance of the relationship between amino acid side chains and gelation conditions. This provides new insights into designs of new functional hydrogels, and may also facilitate various applications in bioengineering. Overall conclusions are contained in the last chapter.

碩士<br>靜宜大學<br>應用化學系研究所<br>92<br>Abstract Room Temperature Ionic Liquids (RTILs) have been widely employed as novel solvents for many applications, such as liquid/liquid extraction, chromatography, synthesis, catalysis etc. This is because of their unique chemical and physical properties of high polarity, high thermal stability, negligible vapor pressure, low toxicity, low melting temperature and good electrochemical stability. Chemical shifts of 1H and 13C NMR of series of imidazolium salts (Br-, BF4- and PF6-) function on the length of alkyl groups on the ring, type of solvents and the concentration. The bromides series demonstrate more chemical shift variation on H(2) upon the change of solvents and concentration. Unexpected H-D exchange reactions were also observed in the bromide series by using CD3OD and D2O. The exchange rates strongly depend on the length of the alkyl group, which could cause more steric factor to reduce the interaction between deuterium atom from solvent and C(2) of the ring.