Le but de cette proposition est d'explorer un nouveau concept de matériaux moléculaires sensibles à l'oxydoréduction. Les architectures commutables électron-sensibles ont longtemps été reconnues comme le choix le plus simple et le plus viable pour produire des dispositifs pratiques, mais la conception efficace de tels systèmes à l'échelle moléculaire reste un défi. L'approche développée dans ce projet repose sur la production électrochimiquement déclenchée de radicaux pi à partir de dérivés de viologène, l'objectif étant d'induire la formation d'une liaison non-covalente et réversible entre ces radicaux pi pour contrôler la conformation des échafaudages supramoléculaires. Les nanomatériaux comprendront des fils moléculaires provenant de polymères de coordination et des fils moléculaires produits par des interactions π le long de l'axe du fil, mis en œuvre par des interactions faibles périphériques telles que l'agrégation des chaînes latérales lipophiles ou la liaison H. Les efforts initiaux se concentreront sur l'optimisation de la formation de π-dimères et de pimer, avec ou sans assistance d'interactions secondaires. Après avoir déterminé les paramètres qui produisent l'auto-assemblage dirigé π le plus efficace, des motifs basés sur les viologènes appropriés seront introduits dans des blocs de construction plus sophistiqués. Tout au long de la synthèse des assemblages, la π-dimérisation utilisée comme force motrice principale pour l'auto-assemblage des nanomatériaux peut être consolidée par un blocage covalent des structures. En fin de compte, l'électrostimulation des systèmes π fournira des assemblages moléculaires dynamiques dans lesquels la morphologie sera sensible aux stimuli redox. / The aim of this proposal is to explore a new concept of redox-responsive molecular materials. Electron-responsive switchable architectures have long been recognized as the most straightforward and viable choice to produce practical devices but efficiently designing such systems on the molecular scale still remains a challenge. The approach developed in this project relies on the electrochemically triggered production of pi-radicals from viologen derivatives, the objective being to induce the formation of non-covalent and reversible binding between these pi-radicals to control the conformation of supramolecular scaffolds. The nanomaterials will comprise molecular wires arising from coordination polymers and molecular wires produced by π-interactions along the wire's axis implemented by peripheral weak interactions such as lipophilic side chain aggregation or H-bonding. The initial efforts will focus on the optimization of π-dimer and pimer formation, with or without assistance of secondary interactions. After determining the parameters that yield the most efficient π directed self-assembly, suitable viologen based motifs will be introduced in more sophisticated building blocks. Throughout the synthesis of the assemblies, π-dimerization that is used as the primary driving force for the self-assembly of nanomaterials may be consolidated by covalent locking of the structures. In the end, the electro-stimulation of π systems will provide dynamic molecular assemblies in which the morphology will be responsive to redox stimuli.

No description available.

The McKay-Alperin-Dade Conjecture, which has not been finally verified, predicts the number of complex irreducible characters in various p-blocks of a finite group G as an alternating sum of the numbers of characters in related p-blocks of certain subgroups of G. The sub-groups involved are the normalizers of representatives of conjugacy classes of radical p-chains of G. For this reason, it is of interest to study radical p-chains. In this thesis, we examine the group L3(2) and determine representatives of the conjugacy classes of radical p-subgroups and radical p-chains for the primes p = 2, 3, and 7. We then determine the structure of the normalizers of these subgroups and chains.

Lyconadin A is a pentacyclic Lycopodium alkaloid isolated from the club moss Lycopodium companatum with anticancer activity. Our approach sought to incorporate a 7-exo–6-exo acyl radical cyclization cascade to access the bicyclo[5.4.0]undecane framework of lyconadin A. Our studies created methodology for the synthesis of 5-alkyl and 3,5-dialkyl-6-carbomethoxy-2-pyridones and sterically demanding epoxide substrates. These epoxide substrates underwent an unanticipated Payne rearrangement.Cranomycin is a potent antibiotic with antiprotozoal activity. Structurally it is a cyclopentane ring system with substitution at each carbon in the ring. Another interesting structural aspect is the existence of three contiguous quaternary stereocenters including two tertiary alcohols and a tert-alkylamine. Our strategy led to the development of a highly diastereoselective synthesis of vicinal tertiary diol systems. We have successfully synthesized the cyclopentenone system shown above, from which we hope to assemble cranomycin.

No description available.

<p>Radical polymers bearing open-shell moieties at their pendant sites offer potential advantages in processing, stability, and optoelectronic properties compared to conventional doped conjugated polymers. The rapid development of radical-containing polymers has occurred across various applications in energy storage devices and electronic systems. However, significant gaps still exist in understanding the key structure-property-function relationships governing charge transport phenomena in these materials. Most reported radical conductors primarily rely on (2,2,6,6-tetramethylpiperidin-1-yl)oxyl (TEMPO) radicals, which raises fundamental questions about the ultimate limits of charge transport capabilities and the impact of radical chemistry choice on material deficiencies. Moreover, an understanding gap persists when it comes to connecting the computable electronic features of individual units and the charge transport behavior of these materials in condensed phases. This dissertation seeks to address these gaps by developing a molecular understanding of charge transport in radical-bearing materials through a combined computational and experimental approach.</p> <p><br></p> <p>The initial stage of this dissertation investigated the impact of dimeric orientations and interactions on charge transport by conducting a density functional theory (DFT) study on a diverse set of open-shell chemistries relevant to radical conductors. The results revealed the anomalously high reorganization energies of the TEMPO radical due to strong spin-localization, which may result in inefficient charge transfer. Additionally, a significant mismatch was identified between dimeric conformations favored by intermolecular interactions and those maximizing charge transfer. This study provided new insights into the impact of steric hindrance and spin delocalization on elementary charge transfer steps and suggests opportunities for exploiting directing interactions to enhance charge transport in these materials.</p> <p><br></p> <p>Building upon these findings, we established a direct relationship between the molecular architecture and intrinsic charge transport properties. To accomplish this, single-molecule characterization methods (i.e., break junction techniques) were implemented to study the nanoscale charge transport properties of radical-containing oligomeric nonconjugated molecules. Temperature-dependent measurements and molecular modeling revealed that the presence of radicals improves tunneling at the nanoscale. Integrating open-shell moieties into nonconjugated molecular structures significantly enhances charge transport, thereby characterizing charge transport through radicals at the individual level and opening new avenues for implementing molecular engineering in the field of nanoelectronics.</p> <p><br></p> <p>To further connect the electronic properties of repeat units with the condensed-phase charge transport behavior of radical polymers, a quantum chemical study was carried out to explicitly evaluate the interplay between polymer design, open-shell chemistries, and intramolecular charge transport. After comprehensive conformational sampling of the configurational space of radical polymers, we determined their anticipated intrachain charge transport values by utilizing graph-based transport metrics. We show that charge transport in radical polymers primarily hinges on the choice of radical chemistry, which in turn affects the optimal selection of backbone chemistry and spacer group to ensure proper radical alignment and prevent undesired trap states. These findings highlight the potential for a substantial synthetic exploration in radical polymers for radical conductors.</p> <p><br></p> <p>In summary, this dissertation provides compelling evidence of radical-mediated charge transport and suggests potential design guidelines to enhance the charge transfer behavior of radical-containing polymer materials. Furthermore, these findings inform future research directions in fine-tuning molecular engineering and modular design to enable the development of radical-based materials and their end-use applications in organic electronics.</p>

En esta tesis se reconstruye y analiza la constitución, desarrollo y trayectoria de la Junta Coordinadora Nacional de la Juventud Radical entre los años 1968 y 1981. Los jóvenes radicales ejercieron un rol significativo en los años setenta tanto en las universidades, a través de Franja Morada, como en la Unión Cívica Radical a partir de su participación en la construcción del Movimiento de Renovación y Cambio. La Coordinadora fue un espacio creado por jóvenes de clase media, en la mayoría de los casos estudiantes universitarios, con el fin de reorganizar y articular a las agrupaciones juveniles de distintas provincias que, a fines de la década de 1960, decían adherir al ideario radical. El pensamiento de raíz nacional-popular, su oposición a la conducción balbinista y el deseo de modernizar el discurso del radicalismo y de reorganizar sus sectores juveniles son tres elementos distintivos de aquella organización. Considerando la imposibilidad de comprender la experiencia de la Coordinadora en toda su dimensión sin contemplar en simultáneo lo que estaba ocurriendo en aquel entonces en el resto del partido radical, esta tesis contiene a su vez una detallada reconstrucción de la trayectoria de la Unión Cívica Radical en los años sesenta y setenta del siglo pasado. Durante aquel período, el radicalismo asistió a una prolongada transición entre la corriente intransigente corporizada en la figura de Ricardo Balbín y el ascendiente espacio renovador que, liderado por Raúl Alfonsín, en la década del ochenta accedería al control del organigrama partidario. El análisis de la constitución y desarrollo de la Junta Coordinadora Nacional es un sendero a través de cuyo recorrido se aspira a contribuir con las investigaciones referidas a una etapa álgida de la historia argentina. Dada la incidencia que la Unión Cívica Radical en general y algunos fundadores de la Coordinadora en particular tendrían durante los años de la transición democrática, la reconstrucción de aquella experiencia contribuye también con los estudios sobre la primera etapa del ciclo postdictatorial al aportar tanto información como nuevas lecturas sobre las trayectorias e ideas de algunos de los protagonistas de la década del ochenta en Argentina. / This thesis reconstructs and analyzes the constitution, development and trajectory of the Junta Coordinadora Nacional [National Coordinating Board] of the Juventud Radical [Radical Youth] between 1968 and 1981. Young radicals played a significant role in the 1970s both in universities, through the Franja Morada, and through their participation in the construction of the Movimiento de Renovación y Cambio [Movement of Renewal and Change]. The Coordinadora was a space created by young middle-class people –university students, most of them– with the purpose of reorganizing and articulating the youth groups of different provinces that, in the late 1960s, claimed to adhere to the radical ideology. National-popular thinking, its opposition to the balbinist leadership and the desire to modernize the discourse of radicalism and reorganize its youth sectors characterized that organization. Considering the impossibility of understanding the experience of the Coordinadora in all its dimension without simultaneously considering what was happening at the time in the rest of the radical party, this thesis contains in turn a detailed reconstruction of the Unión Cívica Radical [Radical Civic Union] during the 1960s and 1970s. In those decades, radicalism witnessed a prolonged transition between the intransigent current embodied in the figure of Ricardo Balbín and the ascendant renovating space that, led by Raúl Alfonsín, would accede in the eighties to the control of the party organization chart. The analysis of the Junta Coordinadora Nacional is a path through which it is hoped to contribute to the studies on a high stage of Argentine history. Considering the impact that the Unión Cívica Radical in general and some founders of the Coordinadora in particular would have during the years of the democratic transition, the reconstruction of that experience also contributes to the studies on the first stage of the postdictatorship cycle by providing information on the trajectories nnd ideas of some of the protagonists of the eighties in Argentina.

Functionalization of hydrocarbons via a free-radical based allyl transfer reaction using various allyl bromide substrates has been previously studied. The work described in this dissertation focuses on the replacement of Br by phthalimido-N-oxyl (PINO ) which helps make this chemistry environmentally friendly. To replace Br with PINO , replacement of previously used allyl-bromide substrates with new allyl-PINO substrates were necessary. Various allyl- PINO compounds were synthesized and the use of these allyl-phthalimido-N-oxyl (allyl-PINO) compounds for the functionalization of various alkyl aromatic hydrocarbons is demonstrated. Kinetic studies were performed to observe the efficiency of the new chain reaction compared to the previously reported studies with allyl-bromides. We recently discovered that these allyl substrates are useful for the functionalization of ethers and acetals. The functionalization of various cyclic and acyclic ethers was performed using these allyl transfer reactions. This reaction was also performed in-solution, which allowed us to perform these reactions at low reagent concentrations. Kinetic chain lengths were measured for these reactions. High chain lengths were observed for all used ethers. Kinetic studies to investigate the rate of radical addition-elimination processes were performed using laser flash photolysis and competition kinetics. These experiments helped us to measure the reactivity and selectivity of PINO as a chain carrier in comparison with Br. Additionally, a new competition experiment was designed to study the relative rate constant for the &#1049109;-fragmentation process. For this experiment a novel substrate that contains two leaving groups, Br and PINO, was synthesized, and the relative rates of elimination of Br vs PINO were compared. / Ph. D.

京都大学 / 新制・課程博士 / 博士(工学) / 甲第24814号 / 工博第5157号 / 新制||工||1985(附属図書館) / 京都大学大学院工学研究科高分子化学専攻 / (主査)教授 山子 茂, 教授 辻井 敬亘, 教授 大内 誠 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DGAM

Call number: LD2668 .T4 1984 G86 / Master of Science