The supramolecular interactions of small organic molecules with different host molecules are investigated in this dissertation. Additionally, the author also describes the self-assembly mechanisms in hydrogen bonding motif. These studies were carried out by many techniques including, NMR, cyclic voltammetry, steady state voltammetry, mass spectroscopy, UV-visible spectroscopy and fluorescence spectroscopy. Chapter 1 introduces the science of supramolecular chemistry and the background of cucurbiturils, one of the most important host molecules studied in this research work. It describes the structures and binding behaviors of each host molecule. Additionally, the selectivity and binding properties in the host-guest interactions involved cucurbiturils are discussed. Chapter 2 compares the electrochemical properties of cationic and neutral ferrocene derivatives upon addition of cucurbiturils. It is observed that the cationic ferrocene compounds bind to cucurbit[7]uril much stronger compared to the neutral ferrocene compounds. The positive charged side chains favor to interact with cucurbit[7]uril portals and thus stabilize the complexes. Besides, the author describes a simple analytical method to determine the binding constants by a competitive binding with a standard reference compound, cobaltocenium, which is reported to bind strongly to cucurbit[7]uril. Chapter 3 described the research of the pH-dependent binding affinity between cucurbit[7]uril and ferrocene guests. The electrochemical behavior of ferrocene moiety in aqueous solution was investigated by cyclic voltammetry in the presence of cucurbit[7]uril in acidic and basic environment respectively. The protonation and deprotonation processes affect the binding behaviors of the ferrocene residues with cucurbit[7]uril. Chapter 4 describes the synthesis and characterization of a new series of 4-phenyl-pyridinium derivatives. These compounds contain a phenyl-pyridinium residue which is favorable to be bound by cucurbit[8]uril. The 1:1 and 1:2 host-guest binding stoichiometries are both observed by UV-visible spectroscopy. These new compounds can be dimerized encapsulated inside the cucurbit[8]uril portals without being electrochemical reduced. Chapter 5 is a brief introduction into the science of hydrogen bonding. This chapter investigates the application of multiple hydrogen-bonding in supramolecular chemistry extensively. Multiple hydrogen bonds with their directionality and reversibility are of great interest and importance in the design and investigations of well-defined supramolecular assemblies. The potential of hydrogen bonding is limitless and is still developing. Chapter 6 describes the synthesis and photochemical behaviors of a series of ureido-pyrimidione derivatives. All of the DDAA derivatives form stable, non-covalent dimers in non-polar solvents. The dimeric molecular assemblies of these hydrogen bonding motifs in their DDAA pyrimidinedione units are investigated by NMR, X-ray crystallography, fluorescence spectroscopy and computations. Additionally, their hetero-dimerization is well studied by fluorescence spectroscopy. The observation and comparison of fluorescence quenching on the photochemical fluorophore for each compound by ferrocene-DDAA and isopropyl-DDAA reveal the electron transfer process through the quadruple hydrogen bonding motifs.

Thesis (Ph. D.)--Washington State University, December 2006. / Includes bibliographical references (p. 122-130).

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The research described here explores the ability of dual H-bond donor catalysts to induce asymmetry in a variety of synthetically useful transformations that proceed via diverse reactive intermediates. In Chapters 1-3, we investigate ureas and thioureas as anion-binding catalysts for asymmetric reactions that proceeed via cationic intermediates with little precedent as electrophiles in asymmetric catalysis. Chapter 4 details our application of H-bond donor catalysis to the Cope-type hydroamination. Chapter 1 describes the development of an asymmetric aldehyde alkylation catalyzed by a bifunctional primary aminothiourea. A variety of 2-aryl propionaldehydes are alkylated with benzhydryl bromides in moderate to good yields and good enantioselectivities. Catalyst structure-activity relationship studies of the alkylation pointed towards electrophile activation by the dual H-bond donor moiety. Experiments aimed at gaining a better understanding of the electophile activation mode and characterizing the activated electrophilic intermediate in the alkylation reaction are described in Chapter 2. The development of an enantioselective cyanide addition to N,N-dialkyliminium intermediates is the subject of Chapter 3. A variety of strategies for accessing N,N- dialkyliminium ions are established, and chiral thioureas are shown to promote the addition of cyanide to such intermediates with moderate enantioselectivities. Chapter 4 details our discovery that thioureas bearing polarizable and conformationally constrained aromatic groups catalyze highly enantioselective Cope-type hydroaminations. This powerful transformation provides a variety of chiral pyrrolidine products under mild reaction conditions. / Chemistry and Chemical Biology

A series of experiments were conducted to explore the hydration state of the mineral lausenite. The experiments of Posnjak and Merwin (1922) were recreated and the conclusion is reached that lausenite is of mineral formula Fe2(SO4)3∙5H2O, rather than Fe2(SO4)3∙6H2O as suggested by Posnjak and Merwin (1922). This conclusion is based on the X-ray diffraction data which found that the Posnjak and Merwin experiments produced a phase whose pattern matched that of the pentahydrate identified by Majzlan (2005). The refractive index data and morphology of this phase is also a match for the mineral described previously as a hexahydrate by Posnjak and Merwin (1922) and Lausen (1928). Synchrotron X-ray diffraction data was collected from a possible new phase in the hydrous ferric sulfate system. The data were analyzed and a unit cell was identified with monoclinic unit cell dimensions of a = 7.532(3)Å b = 12.551(6)Å c = 7.077(4)Å and β = 96.775(8)° with a unit cell volume of 664.4Å3. This phase was determined to grow only at temperatures above 85°C and at a RH of ~23%. The atomic structures of the minerals quenstedtite [Fe2(SO4)3∙11H2O] and romerite [Fe2+Fe3+2(SO4)4∙14H2O] are refined, hydrogen positions are identified and hydrogen bonding scheme is discussed. The weakest hydrogen bonds are found to occur between layers of differently coordinated tetrahedral groups in both romerite and quenstedtite. The transition from romerite to quenstedtite involves the oxidation of the ferrous iron in romerite converting into a Fe3+(SO4)∙5H2O cluster. / Thesis (Master, Geological Sciences & Geological Engineering) -- Queen's University, 2012-09-02 10:11:21.232

When multiple hydrogen bonds lie in-plane and parallel to each other in close proximity, they experience additional positive or negative secondary electrostatic interactions. When a pair of molecules are arranged such that every hydrogen bond acceptor is on one molecule and every hydrogen bond donor is on another, the positive secondary electrostatic interactions are maximised, and thus the association constant of the complex is enhanced. This thesis will present the development of a family of quadruple hydrogen bonded complexes containing only positive secondary interactions, which confers unprecedented stability. The complexes are sufficiently stable to maintain strong binding in polar solvents such as acetonitrile and can be switched “on” and “off” with acid and base. They will be developed into synthons for acid-base responsive supramolecular recognition, for use in stimuli-responsive supramolecular polymers and gelators.

Protonation and hydrogen bonding effects on the redox properties of verdazyl radicals were investigated. Verdazyls with various substituents at the C3 position were synthesized, including species with no basic site, a basic site distant from the verdazyl heterocycle, a basic site proximal to the verdazyl heterocycle but with strained hydrogen bonding geometry, and a basic site proximal to the verdazyl heterocycle with favourable hydrogen bonding geometry. Treatment of these verdazyls with trifluoroacetic acid resulted in several general changes to their cyclic voltammograms: the oxidation and reduction potentials shifted to higher potentials, with concurrent loss of reversibility of the reduction process due to protonation of the verdazylate anion. These changes were likely a result of intermolecular interactions between the substrate and acidic medium rather than specific protonation or intramolecular hydrogen bonding effects. Acid treatment of the verdazyl with favourable hydrogen bonding geometry resulted in emergence of a new reversible process in the CV that was found to match the oxidation process of the corresponding leuco verdazyl. Attempts to synthesize this leuco verdazyl were successful, however purification was not completed. Spectroscopy of the crude product suggests that it may be stable to air, an uncommon feature in leuco species due to their propensity to be easily oxidized by O2. Preliminary investigations of the potential of verdazyls as alcohol oxidation catalysts were made. Several previously reported and novel species were investigated as stoichiometric and catalytic oxidants akin to nitroxides and phenoxyls. It was found that the verdazyls, verdazylium cations and verdazyl-metal complexes tested did not stoichiometrically or catalytically oxidize alcohols. / Graduate

Structural effects in hydrogen and non-hydrogen bonded liquids and their mixtures have been studied using several experimental techniques and theoretical approaches. Apparent heat capacities and volumes of linear alcohols in hydrocarbons were determined at very low alcohol concentrations and their self-association in solution discussed in terms of the Treszczanowicz-Kehiaian theory. An extension of this theory was used to describe cholesterol self-association and its interactions with tripalmitin and lecithin. Heat capacities of water-organic mixtures are reported. It is found that water behaves as a lower alcohol at the organic-rich concentration range. At the water-rich end, Shinoda's views on water structuring around hydrophobes are supported. Thermal pressure coefficients of cyclohexane + normal and branched alkanes are consistent with the presence of orientational order in the long pure n-alkanes. Excess volumes for mixtures of alkanes with liquids of different internal pressures are predicted using Flory theory. The anomalous thermodynamic behaviour of cyclopentane mixed with cyclic and branched alkanes has been studied through the measurement of cyclopentane spin-lattice relaxation times in these mixtures. An extension of Sanchez-Lacombe theory for pure liquids is described and the molecular parameters obtained for sixty common substances. An equation of state for pure n-alkanes with correlations of molecular orientations is presented.

Thesis (Ph. D.)--University of Oregon, 2007. / Typescript. Includes vita and abstract. Includes bibliographical references (leaves 143-150). Also available for download via the World Wide Web; free to University of Oregon users.

Thesis (M.Sc.)--University of Adelaide, Dept. of Chemistry, 2002. / Errata pasted onto front end-paper. Includes bibliographical references (leaves 82-86).