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Showing 1 to 20 of 51 for “"Ion Pairs"”.
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Electron transfer in cyanine borate ion pairs
The ions chosen for our electron transfer studies are cyanine dye acceptors and tetraarylborate donors (see below for representative examples). The two ions are dissolved in a nonpolar solvent to assure a contact ion pair structure. The cyanine is then irradiated, and this induces the electron …
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Structural Investigations of Organoaluminum Compounds and Ion-Pairs
Made available in DSpace on 2015-05-12T22:35:26Z (GMT). No. of bitstreams: 2 license.txt: 4848 bytes, checksum: 96035ab3f5e1c23cc7138a224ce498bd (MD5) 7206873.PDF: 4859588 bytes, checksum: 8d4988a58faa70c8b393577231efeac7 (MD5) Previous issue date: 1971
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Submillimeter Wave Quantum Electronics Using Ion Pairs in Ruby
Made available in DSpace on 2014-12-08T22:23:17Z (GMT). No. of bitstreams: 1 6402977.pdf: 4621523 bytes, checksum: 05f6013efbc155979c50452ef16bff29 (MD5) Previous issue date: 1963
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Biophysical Analyses of Intermolecular Ion-Pairs in Protein-DNA Complexes
… processes, one of the most fundamental interactions is the formation of the ion pair. In protein-DNA complexes, ion pairs form between basic side chains, such as lysine and arginine, and the phosphate backbone of DNA. Moreover, ion pairs are found in dynamic equilibrium between two major states. …
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Structural Studies of Penetrated Ion Pairs Using Chiral Cyanine Borates
… spirobi- ((3-methyl)borataxanthene). Within the ion pair, the cyanine dye exists in two (or more) interconverting conformations of unequal energy. Solid state structural evidence suggests that a nitrogen-forward mode for penetration by the cyanine dominates the solution behavior. A critical …
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The use of ion pairs to increase the percutaneous delivery of diclofenac
Like many topically applied formulations, diclofenac (DF) preparations face delivery challenges due to the highly effective skin barrier. This research explored a novel amino acid-based ion pairing strategy to enhance percutaneous DF delivery through rational counterion selection and solvent …
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A Kinetic and Thermodynamic Study of Exciplex Fluorescence Quenching by Ion Pairs
… in dioxane. However, mechanistic complications are implied by intercepts exceeding unity and by the unequal slopes of these plots. Qualitatively similar behavior is observed when the solvents and electrolytes are varied. Historic conductivity data indicate that the quenching species Q in …
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Computer Simulation of Ion-Induced Nucleation in the Presence of Single Ions and Ion Pairs
… their importance, the mechanisms of their formation are still poorly understood. Ion-induced nucleation may play a role in the process, but details are lacking about how the nucleation rate depends on the size, charge, and number of ions in the cluster. In order to better understand the role that …
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Prediction of electrolyte solution properties using a combined Debye-Huckel, association and solvation model
… model that estimates individual and mean ionic activity coefficients in the NaCl-NaOH-HCl-H₂O system at 25°C. This extra thermodynamic model incorporates long-range electrostatic ion-ion interaction (Debye- Hückel effects), short-range ion-ion interactions (ion association), and …
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Ion Pairing in Aqueous Metal Sulfates and Platinum Group Metal Ammonium Solutions
The structure and dynamics of ions and ion pairs in solution play an integral part in several biological and chemical processes. Historically the calculation of ion pair association constants from computer simulations has been complicated due to the difficulty in validating metal ion force fields …
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Theoretical Study of the Electronic Structure and Reactions Involving Oxygen-Bridged Cu-Pairs in Zeolite Catalysts for Lean Nitric Oxide Abatement
Metal-ion-exchanged zeolite catalysts (e.g., Cu-ZSM-5) are promising candidates for lean NOx automotive exhaust treatment. Despite extensive analysis, the relative importance of isolated metal ions and pairs of metal ions in catalytic chemistry is still unclear. In this investigation, two …
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Anion effects in Homogeneous Palladium and Gold Catalysis
… theme of this work is to use weak interactions to improve transition metal catalysis by studying the ways transition metal cations interact with both traditional and novel weakly-coordinating anions. Understanding of these interactions will better allow synthetic chemists to choose …
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Heats of Dissolution of Several Imidazolium-Based Ionic Liquids into Low Dielectric Media
Ionic liquids (ILs) are salts that are liquid at or near room temperature. They have unique properties since they are completely composed of ions and therefore have many potential applications. This thesis research focuses on the properties of ILs in low polarity solvent, chloroform (CHCl3). The …
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EXPLORATION AND MECHANISTIC STUDY OF WEAKLY COORDINATING ANIONS UNDER THERMAL AND PHOTOCHEMICAL CONDITIONS FOR SELECTIVE TRANSFORMATIONS OF C-C MULTIPLE BONDS
… work has been to acknowledge the effects of anions in transition metal-based systems. In this respect, a novel family of weakly coordinating anions (imadazolylphenyl or IMP anions) in addition to traditional anions were compared under both thermal and photochemical conditions. A significant …
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Light-Induced Electron Transfer and Energy Transfer in Thin Polymer Films and Zeolites
… electron transfer and energy transfer reactions are essential to the collection and storage of light in photosynthesis. The purpose of this work is to better understand both types of reactions, to develop the means to better control them, and to make them more efficient. Electron transfer …
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Studies of the dissociation and energetics of gaseous ions
In this thesis the electron ionization of a number of small gas phase molecules is investigated using pulsed time-of-flight mass spectrometry coupled with a 2-D ion coincidence technique. The simultaneous acquisition of conventional TOF mass spectra and ion coincidence mass spectra, enables …
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ΠΡΟΣΔΙΟΡΙΣΜΟΣ ΠΕΝΙΚΙΛΛΙΝΩΝ ΣΤΟ ΓΑΛΑ ΑΓΕΛΑΔΑΣ ΜΕ ΥΓΡΟΧΡΩΜΑΤΟΓΡΑΦΙΑ ΥΨΗΛΗΣ ΑΠΟΔΟΣΗΣ
… CHROMATOGRAPHIC (HPLC) METHOD FOR THE DETERMINATION OF PENICILLIN G, PENICILLIN V, OXACILLIN AND CLOXACILLIN IN COW'S MILK, HAS BEENDEVELOPED. PENICILLINS ARE EXTRACTED FROM MILK WITH DICHLOROMETHANE. CLEAN UP IS ACCOMPLISHED BY PARTITIONING BETWEEN BUFFERS AND ORGANIC SOLVENTS . PENICILLINS ARE …
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Synthesis and kinetic studies of tricyclic phosphates and phosphonates: Effect of phosphorus-oxide stereochemistry on allylic rearrangements
… is thought to involve S$\sb{\rm N}$1-type ionization leading to an ion-pair. In this work, kinetic studies are reported on tricyclic phosphates and phosphonates which were prepared from 11 and 12 step syntheses. First order rate constants for solvolysis (k$\sb{\rm s}$) and loss of optical …
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Physicochemical Study of Nano-structuring Within Ionic Liquids Using Photoswitchable Spirocyclic Compounds
Ionic liquids (ILs) are presented as novel solvents for the replacement of organic solvents and the formation of smart liquids. The following thesis investigates the proposed nano- and atom-scale structuring of ionic liquids, a feature that appears to totally underpin their unique behavioural …
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Dithioated Phosphates in DNA Duplex Thermodynamics and Protein-DNA Interactions
… at both non-bridging phosphoryl oxygen positions. As an achiral chemical modification of the internucleotide linkage it imparts altered biophysical properties to the phosphate moiety, but still retains normal DNA characteristics such as the ability to form duplexes with complementary strands …
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