Cyclic Aromatic molecules are the subject of continued research due to their highly advantageous characteristics which can be exploited in the areas of pharmaceuticals, material science and nano-electronics. While the defining properties and criteria for a molecule to be considered aromatic are very specific and well established, the degree of aromaticity of these molecules and their corresponding ordering remains a source of continued debate. Given that the macroscopic aromatic properties are fundamentally rooted in the underlying electronic structure and molecular dynamics, these properties can be probed in numerous ways. One such method is to exploit the strong laser field as it pertains to non-linear light-matter interaction. More specifically, the study of photoionization, as a direct resultant effect of strong field light-matter interaction, gives us direct insight into electronic and spatial properties as captured via mass spectroscopy. As a strong-field process, photoionization is effective because the variables that influence its results are also the ones that define aromaticity thus a correlation can be postulated. Other strong field advanced techniques to probe aromacity such as High Harmonic Generation (HHG) have already been successful shown by our group to be effective spectroscopic tools. In this way, photoionization provides supporting evidence to enhance the understanding of these novel spectroscopic tools. This thesis demonstrates that photoionization mass spectroscopy can be used as a probe into the aromaticity order of 5-membered cyclic aromatic molecules. Furthermore, the thesis will show that photoionization results correlate with the previously conducted HHG studies in this area thus further supporting these techniques as sensitive spectroscopic tools into aromaticity. The first part of this thesis describes the characterization of aromatic molecules and the corresponding process to obtain photoionization results that can be correlated to aromaticity. In the second part, these results are compared to the theoretical model and HHG demonstrating consistent results. The third and final component of this thesis describes future work, namely two-colour control of photoionization which is intended to provide greater resolution and variation of photoionization spectra thereby providing a more comprehensive and conclusive understanding of the proposed correlation with aromaticity.

Polycalicenes are novel nonbenzenoid aromatic hydrocarbons made from calicene subunits. A host of related polycalicenes are possible by varying the number of calicenes and the bonding motif of the calicenes (e.g. head-to-tail versus head-to-head). Polycalicenes might posses interesting and useful electrical, magnetic, and optical properties. Especially intriguing is that while calicene has never been synthesized, bicalicene 2, where two calicenes are bonded head-to-tail, has been synthesized by Yoshida et al. and found to be aromatic despite having a peripheral 16 ð electron count. This study details a computational investigation of the aromaticity of some planar polycalicenes using the nucleus independent chemical shift (NICS) criterion of aromaticity. NICS values were calculated with HF/6-31+G(d,p) and B3LYP/6-31+G(d,p). Bicalicene 3, where two calicenes are bonded head-to-head, was shown to have a triplet ground state which required the calculation of NICS values using UB3LYP/6-31+G(d,p). Also, the aromaticities of some “belted” polycalicenes were evaluated using NICS values calculated at 6-31G(d,p). The smaller basis set was used due to the increasing number of basis functions for the larger “belted” polycalicenes. In addition, the electronic ground and excited states of the planar polycalicenes were also calculated. The electronic ground states were assigned using HF/6-31+G(d,p) and B3LYP/6-31+G(d,p). CCSD(T)/6-31G(d,p) calculations were used to confirm assignments. The electronic excited states were calculated using time dependent density functional theory (TDDFT) and B3LYP/6-31+G(d,p). Recently, the reliability of the NICS criterion was questioned when it was claimed NICS found the cyclopropenyl anion to be aromatic. One part of this study details the examination of this claim and concluded that the earlier work was in error. The error was proven to arise from the failure to employ diffuse basis functions in the earlier work.

Thesis (M.Sc.)--Memorial University of Newfoundland, 2005. / Includes bibliographical references.

Thesis (M.S.)--Miami University, Dept. of Chemistry and Biochemistry, 2007. / Title from first page of PDF document. Includes bibliographical references (p. 51-54).

Benzene and its derivatives are ubiquitous in chemical research, with applications ranging from material science to biomedical research. 1,2-Dihydro-1,2-azaborine is a benzene mimic which replaces a CC bond with a BN bond. The basic science and applications of 1,2-azaborines is relatively underdeveloped. This thesis expands the fundamental understanding of 1,2-azaborines. Chapter I describes the air and moisture stability of 1,2-azaborines. Chapter II introduces nucleophilic aromatic substitution reactions that the parent 1,2-dihydro-1,2-azaborine will undergo. Chapter III discusses a trimerization reaction that 1,2-dihydro-1,2-azaborine can perform, which is unique from benzene. Chapter IV examines a novel protection free synthesis of 1,2-azaborines, which provides a more direct route to functionalized 1,2-azaborines. Chapter V discusses the novel deprotection of the N-silicon using an amide, giving one of the first 1,2-azaborine pharmaceutical mimics. Finally, chapter VI summarized miscellaneous contributions I have made to the basic science of 1,2-azaborines. This dissertation includes previously published and unpublished co-authored material. / 10000-01-01

Thesis (Ph. D.)--University of Missouri-Columbia, 2007. / The entire dissertation/thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file (which also appears in the research.pdf); a non-technical general description, or public abstract, appears in the public.pdf file. Title from title screen of research.pdf file (viewed Mar. 4, 2008). Vita. Includes bibliographical references.

Thesis (M.S.)--University of Texas at El Paso, 2009. / Title from title screen. Vita. CD-ROM. Includes bibliographical references. Also available online.

京都大学 / 新制・課程博士 / 博士(理学) / 甲第23022号 / 理博第4699号 / 新制||理||1674(附属図書館) / 京都大学大学院理学研究科化学専攻 / (主査)教授 時任 宣博, 准教授 加納 太一, 教授 依光 英樹 / 学位規則第4条第1項該当 / Doctor of Science / Kyoto University / DGAM

Under current regulations, gasoline engines are facing lubricity and wear challenges that need to be met by enhanced gasoline lubricity. Gasoline lubricity can be enhanced by lubricity improvers such as heavy fatty acid methyl esters. This thesis presents the ‘High Frequency Reciprocating Rig’ (HFRR) tests carried out on a standardized tribological test rig as per a modified version of ASTM D6079, to account for the effects of volatility of gasoline. Testing 5 gasoline types (gasolines A-E) blended with 2 lubricity improver types (LI1-2) at 2 concentrations, 250 and 500 ppm, provided insights on the changes in lubrication behavior with different gasoline composition, LI type, and concentration. The gasoline types with higher aromatic content and average carbon number (lower volatility) resulted in less wear and better lubricity regardless of LI concentration. The highly aromatic gasoline “A” performed better with the fatty acid-based LI1. Gasolines “B-E”, which are less aromatic, resulted in less wear with the ester-based LI2. The decrease in wear volumes with LI2 was more pronounced with the highly volatile gasolines B and E. These insights were mainly challenged by the failure of some tests due to the high volatility of gasoline. To mitigate this effect and confirm the findings, less volatile gasoline surrogates were designed to mimic the composition of the gasoline types on functional group basis, and were blended with the same lubricity improvers, and then tested using the same method. This improved the results and showed that high aromaticity enhanced the lubricity of the gasoline blends, especially with fatty-acid based LI1, but degraded it beyond 50% aromatic content. The enhancement of lubricity with higher average carbon number was also highlighted. To create deeper understanding of the lubrication mechanisms involved, it is recommended to study the rheological properties of the blends, analyze the chemical composition of the deposits on the wear tracks, and repeat the tests with continuous supply of lubricant to further decrease the effect of gasoline volatility

Une série de bisthiényléthènes (BTE), chromophores photochromes, à différents ponts éthène centraux a été synthétisée. Jusque là, la conception rationnelle des BTE a reposé sur la nature des substituants des groupes latéraux. Dans notre travail, nous avons étudié l'influence de l'aromaticité du pont sur les propriétés photochromes. De plus, alors que les cycles à cinq atomes sont le plus souvent utilisés, nous avons introduit des cycles à six atomes au niveau de ce pont. Dans le Chapitre 1, les définitions principales liées au photochromisme, ainsi que des exemples, sont donnés. Le Chapitre 2 est dédié au BTTE, un BTE à pont benzobisthiadiazole, doté d'excellentes propriétés photochromes. Sa fluorescence peut être modulée par solvato- et photochromisme. c-BTTE, l'isomère fermé, a une excellente stabilité dans divers solvants et à l'état solide. Il ne présente pas de retour thermique typique des BTE à pont cyclique à six atomes. Le Chapitre 3 est consacré à des composés comportant des ponts de divers degrés d'aromaticité (BTE-NA, BTA et BTTA). Leur fluorescence peut être modulée par solvato- et photochromisme. Une faible aromaticité peut être corrélée à une irréversibilité thermique, comme illustré par le cas du BTTA à pont benzobisthiadiazole. De plus, la faible barrière énergétique entre les conformations parallèle et anti-parallèle et la grande différence d'absorption entre isomères conduisent à une conversion totale de BTTA à c-BTTA. Des molécules à pont benzothiadiazole, conçues pour la complexation et la commutation de propriétés optiques non linéaires, ont été obtenues (Chapitres 4 et 5). Cependant, pour l'instant, les propriétés visées n'ont pas été mises en évidence. / A series of photochromic bisthienylethenes (BTE) chromophores with different central ethene bridges were synthesized. Up to date, the rational design of BTE have been mainly carried out on the side aryl groups. In our work, the influence of the aromaticity of the central ethene bridge on the photochromic properties was studied. Moreover, unlike in the literature where most of BTE have a five-membered ring bridge, six-membered ring bridges were used. In Chapter 1, examples of photochromes are given, along with the main definitions. Chapter 2 deals with BTTE, a BTE with a benzobisthiadiazole bridge and with excellent photochromic properties. c-BTTE, the closed isomer, exhibits excellent thermal stability in various solvents and in the solid state. Its fluorescence can be modulated by solvato- and photochromism. It eliminates the usual bias of thermal back reaction, typical of BTE with a six-membered ring ethene bridge. Chapter 3 is devoted to compounds with bridges having different aromaticities (BTE-NA, BTA and BTTA). Their fluorescence can be modulated by solvato- and photochromism. The relation between aromaticity and thermal stability was established: the low aromaticity of the central ethene bridge with benzobisthiadiazole unit leads to a thermal irreversibility for BTTA, and the small energy barrier between the parallel and anti-parallel conformers and the great difference in absorption between BTTA and c-BTTA allow the full conversion from BTTA to c-BTTA. Molecules with a benzothiadiazole bridge, designed for complexation and for switchable nonlinear optical properties were prepared (Chapters 4 and 5). However, the targeted properties were not evidenced up to now.