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This Thesis explores the topic of large amplitude motion within molecular machines and the different mechanisms and molecular architectures that are exploited in order to achieve control over the relative positions of submolecular components with respect to one another. Chapter One provides a thorough survey of a vast range of molecular switches and machines that have been developed during the last two decades. The focus is on interlocked and non-interlocked systems that display highly controlled large amplitude motion and the principles that govern their operation. Initially, simple molecular switches and shuttles are described with the chapter finally arriving at complex molecular machines such as motors, ratchets and walking molecules. The importance of understanding the different mechanisms that dictate the operation of switchable molecular machines and their fundamental differences are highlighted throughout the chapter. Chapters Two to Four are devoted to reporting the author’s contributions to novel switchable molecular systems. Chapter Two describes the serendipitous discovery of an ion-pair template which has been exploited in rotaxane formation and the operation of an orthogonal interaction anion-switchable molecular shuttle. The macrocycle moves back and forth along the thread between a cationic pyridinium station and a metal coordinating triazole motif when chloride anions are bound and removed respectively from a palladium centre which is located inside the cavity of the macrocycle. Excellent positional integrity (>98%) of the ring at both stations is achieved due to the orthogonal binding modes in the two states of the shuttle. Chapter Three presents a non-interlocked molecular switch that operates through the manipulation of dynamic covalent chemistry. The switch is comprised of a “two legged”, small organic molecule (a “walking unit”), anchored to a three foothold track via one disulfide and one hydrazone bond. The acid promoted hydrazone exchange allows a specific ratio of the two positional isomers to be achieved at equilibrium. However, the system is also arranged in such a manner that the ratio can be biased towards one positional isomer when the hydrazone exchange is carried out alongside the photoisomerisation (Z  E) of a stilbene motif which is incorporated in the track. The isomerisation alters the relative free energies of the products by increasing the ring strain of one positional isomer with respect to the other, hence introducing bias into the system. The final chapter reports the logical progression of the work presented in Chapter Three and describes the pursuit of a four-station dynamic covalent energy ratchet, of which the net position of the walker unit can be driven away from a steady state, minimum energy distribution by orthogonal disulfide and hydrazone exchange and concomitant stilbene isomerisation. The endeavour towards the successful synthesis of this rather complex molecule is described alongside the principles for its proposed operation. Chapter Two is presented in the form of an article that has already been published in a peer-reviewed journal. No attempt has been made to rewrite this work other than a slight alteration in the order of figures in the text to allow for easier reading and re-formatting to ensure consistency of presentation throughout this thesis. The original paper is reproduced, in its published format in the Appendix. Chapters Two, Three and Four begin with a synopsis to provide a general overview of the work that is presented in addition to a grateful acknowledgement of the contribution of my fellow researchers.

The focus of the research presented in this thesis is the design, synthesis, and anion recognition properties of a structurally novel class of poly(amides) that incorporates the diaminocyclobutenedione (squaramide) group into the polymer backbone. In Chapter 1, a brief overview of different anion-responsive synthetic macromolecules is presented. Emphasis is placed on the wide structural diversity of the polymers, the mechanisms of their anion-induced responses, and features such as signal amplification, multivalency, and cooperative behavior that can be exploited productively in the context of anion recognition and sensing. Chapter 2 describes a new method for the regioselective preparation of squaramides, using Lewis acid-catalyzed condensations of diethyl squarate and different anilines. Zinc trifluoromethanesulfonate promotes efficient condensations of anilines with squarate esters, providing access to symmetrical and unsymmetrical squaramides in high yields from readily available starting materials. Colorimetric anion-sensing behavior and computational studies illustrating the enhanced hydrogen bond donor ability and acidity of squaramides in comparison to ureas are presented. In Chapter 3, the application of the synthetic method described above to the selective preparation of polysquaramides composed of 1,2-isomeric repeat units is described. The optical, thermal and aggregation properties of these materials are also discussed. Finally, Chapter 4 describes self-assembly properties as well as applications of these materials in the area of anion recognition and sensing. Incorporating an anion-binding squaramide group into a polymeric architecture results in drastic alterations in the selectivity and magnitude of its anion-induced response, resulting in a sensitive and discriminating turn-on fluorescence sensor for dihydrogenphosphate ions. This unusual behavior is the result of a cooperative, anion-triggered aggregation process that was further probed by dynamic light scattering (DLS), transmission electron microscopy (TEM) and laser confocal microscopy.

The focus of the research presented in this thesis is the design, synthesis, and anion recognition properties of a structurally novel class of poly(amides) that incorporates the diaminocyclobutenedione (squaramide) group into the polymer backbone. In Chapter 1, a brief overview of different anion-responsive synthetic macromolecules is presented. Emphasis is placed on the wide structural diversity of the polymers, the mechanisms of their anion-induced responses, and features such as signal amplification, multivalency, and cooperative behavior that can be exploited productively in the context of anion recognition and sensing. Chapter 2 describes a new method for the regioselective preparation of squaramides, using Lewis acid-catalyzed condensations of diethyl squarate and different anilines. Zinc trifluoromethanesulfonate promotes efficient condensations of anilines with squarate esters, providing access to symmetrical and unsymmetrical squaramides in high yields from readily available starting materials. Colorimetric anion-sensing behavior and computational studies illustrating the enhanced hydrogen bond donor ability and acidity of squaramides in comparison to ureas are presented. In Chapter 3, the application of the synthetic method described above to the selective preparation of polysquaramides composed of 1,2-isomeric repeat units is described. The optical, thermal and aggregation properties of these materials are also discussed. Finally, Chapter 4 describes self-assembly properties as well as applications of these materials in the area of anion recognition and sensing. Incorporating an anion-binding squaramide group into a polymeric architecture results in drastic alterations in the selectivity and magnitude of its anion-induced response, resulting in a sensitive and discriminating turn-on fluorescence sensor for dihydrogenphosphate ions. This unusual behavior is the result of a cooperative, anion-triggered aggregation process that was further probed by dynamic light scattering (DLS), transmission electron microscopy (TEM) and laser confocal microscopy.

Kyoto University (京都大学) / 0048 / 新制・課程博士 / 博士(工学) / 甲第15039号 / 工博第3188号 / 新制||工||1479(附属図書館) / 27500 / 京都大学大学院工学研究科合成・生物化学専攻 / (主査)教授 濵地 格, 教授 森 泰生, 教授 白川 昌宏 / 学位規則第4条第1項該当

Doctor of Philosophy / Department of Chemistry / Christer B. Aakeroy / A family of bis-pyridine based pharmaceutical active ingredients were synthesized and co-crystallized with four iodoperfluoroalkanes. Thirteen new crystal structures that are driven by I‧‧‧N(py) halogen bonds, are presented and compared with that of their hydrogen-bonded analogues. Halogen bonded co-crystals exhibit two different structural arrangements, as opposed to layered architectures observed in hydrogen bonded co-crystals. In order to explore the effect of aromatic stacking interactions on hydrogen and halogen bond driven co-crystallization process, we utilized a series of aromatic hydrogen and halogen bond donors in combination with bis-pyridine based pharmaceutical active ingredients. Aromatic stacking between the donor and the acceptor were limited, due to the lack of complementarity between the donor and the acceptor in terms of size, shape and geometry. In that case, homomeric interactions between the single components were translated into the structure of the binary co-crystals. According to our charge calculations, similarly activated hydrogen and iodine atoms possess similar electrostatics. Therefore, we wanted to investigate the interchangeability of hydrogen bonds and halogen bonds by utilizing 2-aminopyrimidine as the backbone for C(sp)-H and C(sp)-I functionalities which makes self-complementary ribbons via NH‧‧‧N synthons. Our results show that the ethynyl proton is capable of acting as a synthon mimic of ethynyl iodine by interchangeable C(sp)-H‧‧‧N hydrogen bonds and C(sp)-I‧‧‧N halogen bonds. We exploited the halogen bonding donor capability of iodo, bromo and chloro ethynyl functionalities towards a series of halide ions. Based on the grinding experiments these donors showed 90%, 70% and 50% success rates towards halides. Among the halides, chlorides exhibited the highest red shift compared to bromides and iodides. We synthesized a series of cavitands functionalized with hydrogen bond donor and acceptor groups and studied their binding preferences towards a series of active ingredients. We have shown that suitably functionalized cavitands can act as carriers of active ingredients and especially, selective binding of aspirin is demonstrated using a two-point binding mode.

This thesis describes the synthesis and anion recognition properties of a variety of interlocked host receptors and the application of metal nanoparticles in the areas of catalysis and sensing. <b>Chapter One</b> introduces the field of anion supramolecular chemistry, with particular emphasis on areas relevant to the research discussed in later chapters. Following this, the synthesis and applications of metal nanoparticles are outlined. <b>Chapter Two</b> details the synthesis of a range of halo-triazolium based rotaxanes and explores the effects of altering both the halogen bond donor atom and degree of preorganisation on the anion recognition properties of the interlocked host system. A halogen bond containing catenane is also prepared and its anion binding properties investigated. <b>Chapter Three</b> initially reports the anion-templated synthesis of a series of neutral pyridine N-oxide axle containing rotaxanes before their ability to recognise anions in aqueous solvent mixtures is studied. Attempts to enhance anion binding through the incorporation of a positive charge into the macrocyclic component of the rotaxane structure are also explored. <b>Chapter Four</b> outlines the preparation of β-cyclodextrin functionalised metal nanoparticles and investigations of their catalytic and sensing properties. <b>Chapter Five</b> describes in detail the synthetic and analytical procedures discussed in chapters two to four. <b>Chapter Six</b> summarises the conclusions of this thesis.

No description available.

Analogues structuraux des porphyrines et des Salens, des ligands de type dipyrrométhène bis-phénol ont été étudiés dans notre groupe, notamment sous forme de complexes pour la catalyse d'oxydation. L'activité catalytique de ces complexes étant faible, il a été proposé de remplacer les phénols par des triazoles. L'objet de cette thèse était d'étudier et de valoriser une nouvelle famille de ligands dipyrrométhène bis-triazole.Plusieurs voies de synthèse ont d'abord été étudiées et optimisées pour accéder à ces nouveaux ligands. Nous nous sommes attachés ensuite à valoriser ces nouveaux ligands selon plusieurs axes.Un de ces ligands a été testé en reconnaissance d'anions, ainsi que les dérivés monotriazolium et bis-triazolium. Les triazoliums ont également permis l'accès à des métallocomplexes carbéniques, qui ont été étudiés.Par ailleurs, les métallocomplexes des dipyrrométhène bis-triazole ont été préparés et caractérisés, y compris par électrochimie. Des essais d'utilisation en oxydation ont été entrepris. Enfin, la synthèse de BODIPYs® liposolubles et hydrosolubles a été réalisée. Les propriétés optiques ont été mesurées puis ces dérivés fluorescents ont été testés pour le marquage fluorescent de cellules HeLa / Known as structural analogues of porphyrins and Salens, dipyrromethene bis-phenol-type ligands have been studied in our group, especially as complexes for oxidation catalysis. Due to the poor catalytic activity of these complexes, it has been proposed to replace the phenol moieties with triazoles. The purpose of this thesis was to study and develop a new family of dipyrromethene bis-triazole ligands.Several synthetic routes were first investigated and optimized to reach these new ligands. We then have endeavoured to add value to these new ligands along several lines.The ligand has been tested in anion recognition, as well as monotriazolium and bis-triazolium derivatives. The triazoliums also allowed access to carbene metallocomplexes that were studied.Furthermore, dipyrromethene bis-triazole metallocomplexes were prepared and characterized, notably by electrochemistry. Oxidation catalysis tests were undertaken.Finally, the synthesis of liposoluble and hydrosoluble BODIPYs® was performed. Their optical properties were measured and these fluorescent derivatives were tested for the fluorescent labeling of HeLa cells

This thesis covers the combination of two seperate work accomplished during the throughout the study. In the first part of the study, xanthene based artificial enzymes were synthesized, and kinetic hydrolysis studies done. Artificial enzyme design is an active field of supramolecular chemistry and metalloenzymes are attractive targets in such studies. Enzymatic catalysis is essentially a &lsquo / multifuctional&rsquo / catalysis. As part of our work, we designed and synthesized three novel xanthene derivatives. All three model contain Zn(II) in their active sites. Using the model substrate p-nitrophenyl acetate, we showed that the bifunctional model is at least an order of magnitude more active in catalyzing the hydrolysis of the substrate. Compared to the uncatalyzed hydrolysis reaction of the p-nitrophenyl ester at pH 7.0, the bifunctional model complex showed a 5714-fold rate acceleration. The second part of the thesis involves the design of a dimeric calixpyrrole as a chromogenic chemosensor. Anions are involved in a large number of biological processes and there is an interest in developing molecular sensors for these charged species. The calixpyrroles are a class of old but new heterocalixarene analogues that show considerable promise in the area of anion sensing. In this work, we have designed, synthesized and characterized a calixpyrrole-dimer anion sensor for its anion binding strength. The dimer forms stable complexes with p-nitrophenolate ion. This formed complex is used as a colorimetric sensor by displacing the chromogenic anion with the addition of various anions. like fluoride and acetate. The receptor shows strong affinity and high selectivity for fluoride anion, and also show reasonable affinity toward acetate. Thus, effective optical sensing of biochemically relevant these anions is accomplished using the calixpyrrole dimer.