Although attractive interactions between π systems (π-π interaction) have been known for many years, understanding of its origin is still incomplete. Quantitative measuring of π-stacking is challenging due to the weak nature of the π-π interaction. This dissertation aims at elucidating a quantitative conformational analysis by NMR ring current anisotropy of an organic compound capable of intramolecular π-stacking in solution and studying charge effects on the stacking of π-systems. This dissertation offers four contributions to the area. (1) A general approach to four-state, conformational analysis based on the magnetic anisotropy of molecules undergoing fast dynamic exchange is described. (2) Study unveiled the importance of charges in the conformation of a dication in the solution. (3) Novel aromatic salt pairs of triangulene derivatives with the delocalized cation-anion interaction were synthesized and studied. (4) Study unveiled ionic π-systems preferred face-to-face stacking due to strong cation-π and anion-cation attractions. A general protocol for the application of magnetic anisotropy to quantitative multi-state conformational analysis of molecules undergoing fast conformational exchange was suggested in the current study. The reliability of this method of conformational analysis was checked by the mass balance. VT-NMR was also conducted to study the enthalpic parameters. This technique can be further used to study canonical interactions such as ion pairing, hydrogen boning, and molecular recognition. In the current study, dependence of the probe conformations on the dispersive interactions at the aromatic edges between solvent and probes was tested by conformational distributions of the fluorinated derivatives (2b and 2c) of the probe molecule (1a). Solution and solid studies of these molecules put the previous conclusion drawn by the Cammers group in question. Current studies show that the dispersive interaction at the aromatic edge could not be the predominant force on the conformational changes in the probe molecule 1a during the fluoroalkanol perturbation. This study indicated that charges might be important in the formation of the folding conformations in the solution and solid state of 1a, 2b, and 2c. A contribution of this thesis was to prepare and study a conformational model that lacked charges. The previous molecules were charged. The solid-state structures of pyridinium-derived aromatic rings from the CSD (Cambridge Structural Database) were studied to investigate the π-π interaction between cationic π-systems in solid state. Novel aromatic salt pairs of triangulene derivatives with the delocalized cation-anion interaction were synthesized to study the π-π interaction between two aromatic rings that carried opposite charges. This study showed that the interaction between ionic π-systems can be enhanced by cation-π and anion-cation attractions. The stackings of these π-systems introduce more overlap, closer packing and stronger atomic contact than that of the solid states of comparable neutral species. Cation-π and anion-cation attractions are synergistic in aromatic salts.

Thesis (Ph.D.)--McMaster University (Canada), 1996. / Source: Dissertation Abstracts International, Volume: 58-06, Section: B, page: 3006. Adviser: B. E. McCarry.

Thesis (M.S.)---University of North Carolina Wilmington, 2008 / Title from PDF title page (October 20, 2008) Includes bibliographical references (105-110)

Thesis (Ph.D.) - Simon Fraser University, 2004. / Theses (Dept. of Biological Sciences) / Simon Fraser University.

Thesis (M.S.)--Oregon State University, 2008. / Printout. Includes bibliographical references (leaves 40-46). Also available on the World Wide Web.

The purpose of this dissertation is to investigate the behavior of polycyclic aromatic hydrocarbons (PAHs) in binary solvent systems and determine and/or develop predictive mathematical expressions for describing solutions in which hydrogen-bonding occurs.

京都大学 / 0048 / 新制・課程博士 / 博士(工学) / 甲第19006号 / 工博第4048号 / 新制||工||1623(附属図書館) / 31957 / 京都大学大学院工学研究科高分子化学専攻 / (主査)教授 中條 善樹, 教授 赤木 和夫, 教授 秋吉 一成 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DGAM

京都大学 / 0048 / 新制・課程博士 / 博士(工学) / 甲第20398号 / 工博第4335号 / 新制||工||1672(附属図書館) / 京都大学大学院工学研究科分子工学専攻 / (主査)教授 関 修平, 教授 今堀 博, 准教授 伊藤 彰浩, 教授 白川 昌宏 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DGAM

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The contamination of soils, with polycyclic aromatic hydrocarbons (PAHs), remains a widespread environmental concern. In the past two decades, many physical, chemical and biological methods have been developed and evaluated for the degradation of PAHs. However, due to their low aqueous solubility, high sorption affinity, hydrophobicity and recalcitrance, the environmental remediation of PAHs in soil continues to be economically challenging. In addition to PAH contamination, the presence of oxygenated derivatives of PAHs (OPAHs), in soils, has increasingly become a concern due to their greater toxic properties compared to parent PAH compounds. To date, no investigations on OPAH-remediation methods have been presented in the literature. The use of zero-valent metals (ZVMs) has been reported for several halogenated contaminants in solution systems, but the effectiveness of ZVM to degrade sorbed PAHs and OPAHs has been rarely addressed. This present research focuses on the development of a combined technique for the feasible desorption and degradation of PAHs and OPAHs in soils. PAH and OPAH degradation efficiency, using activated magnesium (Mg) metal combined with an ethanol-ethyl lactate cosolvent (1:1 ratio), was initially examined in soil-free systems. This metal/cosolvent system demonstrated adequate degradation (above 80%) for high-molecularweight (HMW) PAHs, which were subsequently converted into hydroaromatic compounds; while OPAHs were degraded and converted into hydroxylated or hydrogenated derivatives. Further soil-free studies revealed that the degradation rate was affected by the surface or reactive iv sites of the metal and that optimum degradation efficiency were obtained with Mg ball milled with graphite (Mg/C). In a bench-scale feasibility test, the efficacy of this system was assessed on a soil spiked with a mixture of three HMW PAHs compounds and three OPAHs compounds with amounts ranging from 0.033 mmol to 0.060 mmol. The experimental results show that 2 mL of an ethanol-ethyl lactate solvent mixture resulted in 58% to 85% extraction efficiency for the selected contaminants in 1 g of spiked soil, followed by 64 - 87% degradation efficiency of the extracted contaminants with 4.11 mmol of the activated metal. This activated-Mg/cosolvent system can be considered as a promising alternative method for ex situ remediation of PAH and OPAH-contaminated soils.