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Polypyrrolic systems : anion binding, photophysical properties, and electron transfer / Anion binding, photophysical properties, and electron transferKarnas, Elizabeth Theresa 15 February 2012 (has links)
Anion Binding has recently emerged as an important field of study due to the role these small inorganic species play in a plethora of biological processes. Chapter 1 of this thesis describes the biological relevance and scientific justifications for studying the ability of synthetic molecules to transport or extract anions under interfacial conditions. This chapter also serves to underscore the need to study both the thermodynamics and kinetics of anion binding as achieved using synthetic receptors. Methods for determining the thermodynamics of ion recognition are well-developed, and many equilibrium analyses of supramolecular binding events have been reported; however, the kinetics of such interactions are often neglected. Chapter 2 details the author's efforts to address this deficiency with respect to anion-binding and reports progress towards quantitative kinetic analyses of the interaction between cyclo[8]pyrrole (C8), an expanded porphyrin, and two test anions. It has been determined that stopped-flow analysis can provide on and off-rates, as well as activation parameters not accessible through thermodynamic means. Initial flash photolysis kinetic studies have also revealed that C8 has the potential to act as a photosensitizing agent through electron donation. This work is presented in Chapter 3, wherein the author discusses the construction of novel donor-acceptor dyads based on C8. As detailed in this chapter, time-resolved optical analyses have confirmed that photoinduced electron transfer occurs under conditions of photoexcitation and that the lifetime of the charge separated state is approximately 300 [mu]s. Finally, Chapter 4 describes a comprehensive set of spectroscopic work conducted by the author involving porphyrin and porphycenes that have a RuCp* (Cp*: pentamethylcyclopentadienyl) fragment either coordinated to the central porphyrinic core or directly attached to the "[pi]-face" of the macrocycle. These systems display unique intramolecular electron transfer properties that are ascribed to the metallated-porphyrin core acting as an electron acceptor, as opposed to a donor as is normally observed with porphyrins. / text
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Tetrathiafulvalene Schiff-base ligands and anion receptorsBejger, Christopher Michael 12 November 2013 (has links)
Over the last decade, the classic organic donor tetrathiafulvalene (TTF) has emerged as an important functionality in supramolecular systems and complex ligand chemistry. Due to synthetic advances, TTF is no longer a moiety strictly limited to the area of charge transfer salts in material science. In fact, many complex systems incorporating the electron rich donor system are known. More can be imagined. This doctoral dissertation describes the author's journey in designing, synthesizing, and studying various compounds in which the TTF moiety serves a practical purpose, oftentimes giving known molecules new functions. The reported findings have led to a greater understanding of anion binding effects on TTF-containing anion receptors, the use of transition metals to pre-organize [pi]-faces for through-space donor-acceptor interactions, and the introduction of actinide species to tetrathiafulvalene ligands. The first Chapter provides a brief introduction and a short history of TTF chemistry. It also provides an overview describing the fundamental properties of TTF compounds, including TTF dimeric behavior and redox properties. Chapter 2, as the major focus of this dissertation, details the use of a flexible TTF-modified macrocyclic ligand, which upon metallation can effectively preorganize two TTF units to interact when oxidized. Specifically, a new way to stabilize the through-space mixed-valence TTF dimer, in which a transition metal can affect the degree of interaction between the two TTF units, is described. The mixed-valence TTF species in question could see use as components in molecular machines and could play an important role as molecular organic conductors, and discussions along these lines are included in this chapter. These mixed valence complexes were investigated by spectroscopic (¹H-NMR, UV-Vis NIR titrations, and EPR analysis) and X-ray single crystallographic analyses involving both the neutral and oxidized products. Chapter 3 introduces the synthesis, characterization, and electrochemistry of the first TTF-ligand to form a complex with an actinide cation. Chapter 4 details the synthesis, binding studies and X-ray single crystallographic analyses of a TTF-based electrochemical sensor for dihydrogen phosphate anion detection. Experimental procedures and characterization data are reported in Chapter 5. / text
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Synthesis, anion binding, and photophysiscal properties in polypyrrolic systemsVargas-Zúñiga, Gabriela Idania 03 March 2014 (has links)
Anion binding has emerged as an important field of study due to the role that anionic species play in nature. As a consequence, considerable effort has been focused on the generation of anion receptors. These receptors have been designed to recognize anions through interactions, such as hydrogen bonding, donor-acceptor, and hydrophofic effects, in order to achieve higher sensitivity and selectivity. Another approach involves ion pair recognition, wherein the anions and cations are bound to the same system. Specifically, receptors bearing both hydrogen bonding donor and cation coordination sites have been of great interest as systems that lead to anion recognition and enhanced anion selectivities. Chapter 1 of this dissertation describes efforts to develop systems on the basis of modified Schiff-base calixpyrroles. This modification was achieved by incorporating a “strap” across the macrocycle to produce the so-called strapped Schiff-base calixpyrroles. The strap bearing amides are known to act as hydrogen bonding donors that can isolate the binding site from the medium. On the other hand, Schiff-base calixpyrroles have been widely studied as multidentate ligands for metal cation coordination. Therefore, the synthetic combination of these two moieties might provide a system wherein an ion pair complex is formed. Strapped Schiff-base calixpyrrole palladium complex were found to bind selectively cyanide anions.
The effects of direct substitution on one meso position on the optical and photophysical properties of porphycenes was recently found to be dependent of the electronic properties of the substituten (e.g., electron donor or electron withdrawing group). However, the effects on the electronic and optical properties properties as a result of substitution through a conjugated spacer are as yet unknown. This led to the synthesis of four meso substituted etioporphycenes, which are described in Chapter 2. Here, the substitution through an ethenyl group was stablished by analytical and structural means. This chapter provides of a description of the spectroscopic, structural and voltamperometric features of these compounds. Experimental procedures and characterization data are reported in Chapter 3. / text
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Nongenomic Effects of Fluticasone Propionate and Budesonide on Human Airway Anion SecretionHasegawa, Yoshinori, Imaizumi, Kazuyoshi, Kondo, Masashi, Sato, Mitsuo, Hashimoto, Naozumi, Ito, Satoru, Matsuno, Tadakatsu, Hibino, Yoshitaka, Ito, Yasushi, Morise, Masahiro, Mizutani, Takefumi 11 1900 (has links)
名古屋大学博士学位論文 学位の種類 : 博士(医学)(課程) 学位授与年月日:平成25年3月25日 水谷武史氏の博士論文として提出された
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Neue künstliche Guanidiniocarbonylpyrrol-Rezeptoren zur Komplexierung von Oxo-Anionen in WasserBickert, Volker January 2008 (has links)
Würzburg, Univ., Diss., 2008
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Anion and solvent influences on the self-assembly of copper(I) coordination solidsKnight, Douglas A., January 2005 (has links)
Thesis (Ph. D.)--University of Missouri-Columbia, 2005. / 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 on (November 8, 2006) Vita. Includes bibliographical references.
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Anioneneinfluss auf die elektrochemische Metallabscheidung Blei auf Kupfer(111) /Duisberg, Matthias. Unknown Date (has links) (PDF)
Universiẗat, Diss., 2001--Bonn.
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In-situ-STM-Studie zum Anioneneinfluss auf die Abscheidung von Cadmium auf KupferelektrodenHommrich, Joerg. Unknown Date (has links) (PDF)
Universiẗat, Diss., 2003--Bonn.
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Ultraschnelle zeitaufgelöste Pump-Probe-Photoelektronenspektroskopie an isolierten und massenselektierten AnionenEhrler, Oli T. January 2006 (has links)
Zugl.: Karlsruhe, Universiẗat, Diss., 2006.
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Theory and Applications of Aryl CH Hydrogen Bonds in Arylethynyl ReceptorsTresca, Blakely 21 November 2016 (has links)
Design of selective non-covalent binding systems for chemical and biological recognition requires an intimate understanding of the factors that control the strength of each interaction. Weak interactions such as anion-Π, Π-Π, and CH-Π are understood to be important contributors to the overall binding of ligands, however, these interactions are almost purely electrostatic. Aryl CH hydrogen bond donors are a recent addition to the field and provide new possibilities by introducing a partial covalent character, which imparts greater directionality and acceptor preference. CH hydrogen bonds, and other similar weakly polarized donors, are an exciting development in supramolecular chemistry because of their ubiquity, stability and structural diversity. The use of experimental and computational techniques in this dissertation has provided us with a new understanding of the energetic factors that control CH hydrogen bond strength and selectivity for anion binding.
2,6-bis(2-anilinoethynyl) receptors with an aryl CH donor as the central arene act as anion receptors with one CH hydrogen bond and four supporting NH hydrogen bonds around a semi-preorganized pocket. The scaffold provides an efficient route to substitution para to the donor, which allows for tuning of optoelectronic properties and the measurement of linear free energy relationships (LFERs) on anion binding. Association constants with anions, Cl<sup>-</sup>, Br<sup>-</sup>, I<sup>-</sup>, NO3<sup>-</sup>, were measured by <sup>1</sup>H NMR and UV-vis spectroscopy in water
saturated chloroform. The solution data was combined with calculated and empirical measurements to provide LFERs and identify an anion dependent substituent character. The importance of substituent resonance or inductive character has been further probed by measuring the isotope effect of selective monodeuteration. Solution measurement of a normal equilibrium isotope effect points to the role of covalency in this non-traditional hydrogen bond. The application of this new understanding to developing fluorescent probes for biological and environmental anions is demonstrated with a small receptor array.
This dissertation includes both previously published and unpublished co-authored material.
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