In an age in which the microchip is ubiquitous, the rewards for novel methods of microfabrification are great, and the vast possibilities of nanotechnology lie just a little ahead. Various methods of microlithography offer differing benefits, and even as older techniques such as optical lithography are being refined beyond what were once considered their upper limits of resolution, new techniques show great promise for going even further once they reach their technological maturity. Recent developments in optical lithography may allow it to break the 100-nm limit even without resorting to x-rays.

Thesis (Ph.D.)--Ohio University, June, 2008. / Abstract only has been uploaded to OhioLINK. Includes bibliographical references (leaves 199-209)

No description available.

En combinant l’expertise du Cermav dans la conception de films minces de très haute résolution obtenus par auto-assemblage de glycopolymères biosourcés et le savoir-faire du LETI sur les procédés de lithographie innovante, l’objectif de ce projet de thèse est d’évaluer ces nouveaux copolymères biosourcés -associant des oligosaccharides- comme solution alternative pour la nano lithographie de demain. En effet, ces dernières années l’équipe de « Physico-chimie des glycopolymères » du Cermav dirigée par R. Borsali a développé une nouvelle classe de glycopolymères (type PS-Maltoheptaose, PCL-Maltoheptaose, Xyloglycan-PSSI) pouvant s’auto-organisér avec une résolution de 5nm, dépassant ainsi largement la résolution atteinte aujourd’hui par les seuls copolymères à blocs issus du pétrole type PS-PMMA (20nm). En parallèle, durant les deux dernières années, le Cea/Leti a validé le potentiel des procédés basés sur l’auto assemblage des copolymères à bloc type PS-b-PMMA (résolution 20nm) comme solution alternative aux techniques de lithographie actuelles. Ces résultats positionnent le Cea/Leti dans l’état de l’art international et constituent une bonne base pour intégrer, dans le domaine de la nano-electronique, de nouveau systèmes à plus forte résolution (<10nm), tels que ceux développés par le Cermav. Le travail de thèse proposé se déroulera en trois temps : – Dans un premier temps le candidat adressera la synthèse et la caractérisation de nouveaux copolymères à blocks hybrides associant des oligosaccharides. – Ensuite il va d’intéressé à l’élaboration de glycofilms nano-organisés ainsi que à l’identification des facteurs importants jouant sur la nano-organisation. – Et finalement le contrôle de l’organisation à l’échelle nanométrique par grapho-épitaxie pour des applications lithographiques sera adressé. Deux applications seront visées : le contact et la ligne (phases cylindriques et lamellaires). La compatibilité du procès avec les contraintes de la micro-électronique sera également détaillée. / Combining the Cermav expertise in the thin films design with very high resolution obtained by self-assembly of glycopolymers biobased and the know-how of LETI on innovative lithography processes, the objective of this thesis is to evaluate these new bio-based copolymers, combining-oligosaccharides as an alternative for nano lithography tomorrow. Indeed, in recent years the team of "Physical Chemistry of glycopolymers" of Cermav directed by R. Borsali has developed a new class of glycopolymers (PS-maltoheptaose, PCL-maltoheptaose, Xyloglycan-PSSI) can self-organize with a resolution of 5 nm, far surpassing the resolution reached today only by block copolymers from Oil PS-PMMA (20 nm). In parallel, during the last two years, Cea / Leti has validated the potential methods based on self-assembly of block copolymers PS-b-PMMA (20 nm resolution) as an alternative to the current lithography techniques. These results position the Cea / Leti in the international state of the art and provide a good basis for integration in the field of nano-electronics, new systems with higher resolution (<10 nm) as those developed by the Cermav. The proposed thesis work will take place in three stages: - First time candidate address the synthesis and characterization of new copolymers blocks combining hybrid oligosaccharides. - Then he's going to be interested in the development of nano-glycofilms organized as well as to identify important factors playing on the nano-organization. - And finally the control of the organization at the nanoscale by grapho-epitaxy for lithographic applications will be addressed. Two applications are described: the contact line (cylindrical and lamellar phases). Compatibility constraints trial microelectronics will also be detailed.

Despite the prevalence of supramolecular architectures derived from metal-ligand or hydrogen-bonding interactions, few studies have focused on the simultaneous use of these two strategies to form discrete metal-ligand hydrogen-bonded (MLHB) assemblies. The design, synthesis, and characterization of 2-quinolone based hybrid subunits, 7-DPQ and 5-PYQ, that contain phosphine and pyridyl metal binding sites, respectively, is reported. Both subunits give two-fold symmetric hydrogen-bonded tectons that assemble with metal precursors to give hybrid MLHB structures. Treatment of [Cp*RhCl2]2 with the 7-DPQ subunit yields hybrid MLHB assemblies with closed topology. 1H diffusion ordered spectroscopy experiments established the stability of the structures in solution, and the measured hydrodynamic radii match those determined crystallographically, suggesting that the closed topology is maintained in solution and the solid state. In order to further explore possible MLHB architectures and test the selectivity boundaries of our quinolone-based subunits we report the selective assembly of 5-PYQ with mono- and bis-platinated anthracene precursors. Addition of 5-PYQ to [1-trans-Pt(PEt3)2NO3]-8-chloroanthracene yielded a hybrid MLHB structure with preorganization for a hybrid MLHB polymer. Despite the systems preorganization for the hybrid polymeric structure the assembly of 5-PYQ with 1,8-bis(trans-Pt(PEt3)2NO3)anthracene selects only for one discrete closed self-assembled macrocycle. The strong π-π stacking interactions of the 5-PYQ subunits erode the hydrogen-bonding fidelity to favor ambidentate coordination modes of 5-PYQ and give the non-hybrid macrocycle. In the course of investigating the intricacies of hybrid MLHB supramolecular structures we observed that, in addition to metal-ligand and hydrogen-bond interactions, the π-π stacking interactions of the 7-DPQ and 5-PYQ subunits played a critical role in determining the final assemblies. In fact, the prominent π-π interactions were typically found to be more favorable than the quinolone interligand hydrogen-bonding interactions. These results contribute to the overall knowledge of the design principles, synthesis, characterization, and fundamental assembly trends when exploiting both hydrogen-bonding and metal-ligand interactions to form stable supramolecular architectures. These studies have provided the foundation for expanding the accessible space of supramolecular chemistry to include rationally designed hybrid MLHB systems to give structures that more closely mimic the complex supramolecular systems observed in Nature. This dissertation includes both previously published/unpublished and co-authored material. / 10000-01-01

Knots are being discovered with increasing frequency in both biological and synthetic macromolecules and have been fundamental topological targets for chemical synthesis for the past two decades. However, only few synthetic molecular knots have been prepared to date and their properties remain largely unexplored. This thesis reports the synthesis of the most complex non-DNA molecular knot prepared to date: the self-assembly of five bis-aldehyde and five bis-amine building blocks around five metal cations and one chloride anion forms a 160-atom-loop molecular pentafoil knot (five crossing points). Chapter I aims to give the reader an overview of the current state of research in the field of template synthesis of molecular knots. Chapter II reports the synthesis and full characterisation of the most complex non-DNA molecular knot prepared to date, a pentafoil knot. Chapter III describes the synthesis of eleven pentameric cyclic double helicates derived from the scaffold of a pentafoil knot and presents an extensive study of the factors influencing the assembly process. Chapter IV reports the study of the self-sorting behaviour of a molecular Solomon link and a molecular pentafoil knot and their related non-interlocked systems. Chapter V the dynamic nature of pentameric circular helicates and a pentafoil knot is investigated, bringing insights on the subtle balance of thermodynamic and kinetic parametres involved in their self-assembly process. Chapter VI describes the halide binding properties of a synthetic molecular knot and doubly- and triply-entwined [2]catenanes based on circular Fe(II)-double-helicate scaffolds.

This thesis presents the synthesis and characterisation of a range of heterometallated porphyrin oligomers and other novel 3D π-conjugated porphyrin nanostructures. Subsequently, their physical organic properties were evaluated which revealed some fascinating electronic properties. Chapter 1 summarises some of the work done in the Anderson group on porphyrin nanostructures and reviews the literature regarding heterometallated porphyrin oligomers. In addition it introduces the main concepts and techniques used in the remainder of the thesis. In Chapter 2 the stabilities of a family of four linear porphyrin pentamer complexes are determined by UV-vis-NIR titrations and analysed using chemical double-mutant cycles which reveal that the binding energy of the copper centre to an axial pyridine ligand is -6.2 kJ mol^-1. Subsequently, the Zn-Zn-Cu-Zn-Zn pentamer is used in the synthesis of a heterometallated 10-porphyrin nanoring. Chapter 3 will describe the investigation of quantum interference phenomena in a bis-copper six-porphyrin nanoring by using EPR spectroscopy. We show that the exchange coupling between two spin centres is increased by a factor 4.5 in the ring structure with two parallel coupling pathways as compared to an otherwise identical system with just one coupling path. In Chapter 4 the syntheses of three isomers of the bis-copper 6-porphyrin nanoring are described. DFT calculations have indicated potential destructive interference phenomena in one of the isomers which would allow for the formation of a molecular system with behaviour resembling that of a hypothetical molecular interferometer. Chapter 5 reports on the template-directed synthesis of a π-conjugated 14-porphyrin nanoball. This bicyclic structure consists of two intersecting nanorings of 6 and 10 porphyrin units. Fluorescence up-conversion spectroscopy experiments demonstrate that electronic excitation delocalises over the whole 3D π-system within 0.3 ps if the nanoball is bound to its templates or within 5 ps if the nanoball is empty. In Chapter 6 the synthesis and characterisation of a D_4h symmetric analogue of the porphyrin nanoball is described. The structure consists of ten porphyrin units arranged as two perpendicular 6-porphyrin nanorings intersecting at two porphyrins. In the synthesis, a combination of magnesium and zinc porphyrins are used which allows for the introduction of a selective demetallation method crucial for accessing this novel structure.

Syntheses, spectral, electrochemical and spectroelectrochemical studies of phenylthio and amino derivatised metallophthalocyanines complexes are reported. The complexes are immobilized onto a gold macro disk, gold ultramicroelectrode and gold coated fiber electrodes via self assembly with phenylthio MPc derivatives or onto a glassy carbon electrode via electropolymerisation with amino MPc derivatives. For the first time MPc SAMs were formed on gold coated fiber. The electrocatalytic behavior of the modified electrodes was studied for the detection of nitrite and L-cysteine, all modified electrodes showed improved electrocatalytic oxidation compared to the unmodified electrode. The MPc complexes catalyzed nitrite oxidation via a two-electron mechanism producing nitrate. Cobalt tetraaminophthalocyanine showed the best catalytic activity for nitrite oxidation in terms of overpotential lowering compared to other complexes and thus was used for nitrite detection in a food sample, the nitrite concentration was determined to be 59.13 ppm, well within the limit for cured meat products. Electrocatalytic oxidation of L-cysteine on SAM modified gold coated fiber was reported for the first time. The gold coated fiber and ultamicro cylinder electrode were less stable towards the electro-oxidation of cysteine compared to its oxidation on the gold disk. The gold disk electrode gave better catalytic performance in terms of stability and reduction of overpotential. The phenylthio cobalt phthalocyanine derivative gave the best catalytic activity for L-cysteine oxidation in terms of overpotential lowering compared to other phenylthio derivatized MPc complexes. The amount of L-cysteine in human urine was 2.4 mM, well within the urinary L-cysteine excretion range for a healthy human being.

abstract: Rubisco activase (Rca) from higher plants is a stromal ATPase essential for reactivating Rubiscos rendered catalytically inactive by endogenous inhibitors. Rca’s functional state is thought to consist of ring-like hexameric assemblies, similar to other members of the AAA+ protein superfamily. However, unlike other members, it does not form obligate hexamers and is quite polydisperse in solution, making elucidation of its self-association pathway challenging. This polydispersity also makes interpretation of traditional biochemical approaches difficult, prompting use of a fluorescence-based technique (Fluorescence Correlation Spectroscopy) to investigate the relationship between quaternary structure and function. Like cotton β Rca, tobacco β Rca appears to assemble in a step-wise and nucleotide-dependent manner. Incubation in varying nucleotides appears to alter the equilibrium between varying oligomers, either promoting or minimizing the formation of larger oligomers. High concentrations of ADP seem to favor continuous assembly towards larger oligomers, while assembly in the presence of ATP-yS (an ATP analog) appears to halt continuous assembly in favor of hexameric species. In contrast, assembly in the “Active ATP Turnover” condition (a mixture of ATP and ADP) appears to favor an almost equal distribution of tetramer and hexamer, which when compared with ATPase activity, shows great alignment with maximum activity in the low µM range. Despite this alignment, the decrease in ATPase activity does not follow any particular oligomer, but rather decreases with increasing aggregation, suggesting that assembly dynamics may regulate ATPase activity, rather than the formation/disappearance of one specific oligomer. Work presented here also indicates that all oligomers larger than hexamers are catalytically inactive, thus providing support for the idea that they may serve as a storage mechanism to minimize wasteful hydrolysis. These findings are also supported by assembly work carried out on an Assembly Mutant (R294V), known for favoring formation of closed-ring hexamers. Similar assembly studies were carried out on spinach Rca, however, due to its aggregation propensity, FCS results were more difficult to interpret. Based on these findings, one could argue that assembly dynamics are essential for Rca function, both in ATPase and in regulation of Rubisco carboxylation activity, thus providing a rational for Rca’s high degree of polydispersity. / Dissertation/Thesis / Doctoral Dissertation Biochemistry 2018

abstract: The discovery of DNA helical structure opened the door of modern molecular biology. Ned Seeman utilized DNA as building block to construct different nanoscale materials, and introduced a new field, know as DNA nanotechnology. After several decades of development, different DNA structures had been created, with different dimension, different morphology and even with complex curvatures. In addition, after construction of enough amounts DNA structure candidates, DNA structure template, with excellent spatial addressability, had been used to direct the assembly of different nanomaterials, including nanoparticles and proteins, to produce different functional nanomaterials. However there are still many challenges to fabricate functional DNA nanostructures. The first difficulty is that the present finite sized template dimension is still very small, usually smaller than 100nm, which will limit the application for large amount of nanomaterials assembly or large sized nanomaterials assembly. Here we tried to solve this problem through developing a new method, superorigami, to construct finite sized DNA structure with much larger dimension, which can be as large as 500nm. The second problem will be explored the ability of DNA structure to assemble inorganic nanomaterials for novel photonic or electronic properties. Here we tried to utilize DNA Origami method to assemble AuNPs with controlled 3D spacial position for possible chiral photonic complex. We also tried to assemble SWNT with discrete length for possible field effect transistor device. In addition, we tried to mimic in vivo compartment with DNA structure to study internalized enzyme behavior. From our results, constructed DNA cage origami can protect encapsulated enzyme from degradation, and internalized enzyme activity can be boosted for up to 10 folds. In summary, DNA structure can serve as an ideal template for construction of functional nanomaterials with lots of possibilities to be explored. / Dissertation/Thesis / Ph.D. Chemistry 2013