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Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 58 for “"ion pairing"”.
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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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Development of polymeric nanoparticulate formulation encapsulating protein molecules following hydrophobic ion pairing complexation
Several formulation strategies have been employed to enable sustained delivery of antibody therapeutics by nanoparticulate based dosage forms. However, development of sustained release nanoparticulate based dosage form for protein therapeutics represents a real challenge to scientists. These …
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An Exploration of Ion Pairing Interactions as a Tool to Control Regioselectivity in Iridium-Catalysed C–H Borylation
… by their use in nature, non-covalent interactions have recently started being used in small molecule catalysis for control of selectivity. To date, this has been particularly fruitful in the area of enantioselective catalysis when using ion pairing or hydrogen bonding. Despite the success seen …
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Development of Ion Pairing Strategies that Utilise Cations to Control Selectivity in Transition Metal-Catalysed Functionalisation of C–H Bonds
… incorporating attractive non-covalent interactions have emerged as a powerful tool to control selectivity in organic synthesis through small molecule catalysis. The ubiquity of charged intermediates across these transformations has recently highlighted ion pairing as a promising interaction to …
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The Application of Catalysis based on Hydrogen Bonding and Ion-pairing Interactions to Asymmetric Minisci-type Alkylations of Azines and Iridium-Catalysed C-H Borylation.
Recent advances in the incorporation of attractive non-covalent interactions into small molecule catalysts have greatly increased the understanding of how such approaches can be applied to regioselectivity and enantioselectivity challenges in synthetic chemistry. The most widely used interactions, …
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New Catalysts for Asymmetric Nitrene Transfer Based on Ion-Pairing Between Sulfonated Rhodium(II,II) Tetracarboxylates and Chiral Cations: Design, Synthesis and Applications to Enantioselective Carbon-Nitrogen Bond Formation
… for Asymmetric Nitrene Transfer Based on Ion-Pairing Between Sulfonated Rhodium(II,II) Tetracarboxylates and Chiral Cations: Design, Synthesis and Applications to Enantioselective Carbon-Nitrogen Bond Formation – Alexander Fanourakis The work presented in this thesis investigates a new …
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Controlling the Regio- and Enantioselectivity of Iridium-Catalysed Arene Borylation Using Sulfonated Bipyridine Ligands
Non-covalent interactions are commonly used in nature to control the selectivity of chemical transformations. Inspired by this, synthetic chemists have begun to use them to control selectivity in small molecule catalysis. Two types of interaction that are frequently exploited are hydrogen bonding …
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The Investigation of Primary and Secondary Modifiers in the Extraction and Separation of Neutral and Ionic Pharmaceutical Compounds with Pure and Modified Carbon Dioxide
A successful supercritical fluid extraction method includes removal of the analyte from the matrix into the bulk fluid as well as trapping or concentration of the analyte prior to analysis. In the first phase of this research, the trapping capacities of three solid-phase traps (glass beads, 50/50 …
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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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Electro-reduction of bromate on mercury
<p>"The electrochemical reduction of BrO⁻₃ was studied on a stationary Hg electrode in neutral and basic solutions containing K⁺, Na⁺, and L⁺. Coulombic efficiency studies showed Br⁻ to be the predominant reduction product. The steady state kinetic parameters include Tafel slopes of ca. -0.120 V, …
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Synthesis and Physical Investigation of some Organotellurium Compounds
… of these in DMSO and DMF show that considerable ion pairing occurs in solution. The compounds show stability toward the reductive elimination of alkyl halides in solutions such as CHC13, DMSO and DMF. The idea of association of the telluronium salts is now firmly established, and is supported by …
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Heavy metal interactions with nucleic acid derivatives : a nuclear magnetic resonance study
The aqueous solution conformation of SAH and SAM has been investigated using lanthanide probes. SAH at pH 7.0 interacts normally with lanthanide aquo ions and lanthanide-EDTA complexes via coordination at the carboxyl group. The conformation of the homocysteine fragment is found to, be extended but …
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Calcium carbonate precipitation kinetics
A modified equation from that of Nancollas and Reddy is presented to describe the rate of calcium removed from water in CacO3; precipitation. The mass of CaCO3; precipitated at any moment was obtained by monitoring pH and utilizing this in the equilibrium equations for the Ca - H2CO3 system …
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Molecular modeling of water and aqueous electrolytes under electric field: thermal, dielectric, and transport properties
… behavior remains a challenge in MD simulations. This study combines machine learning, and MD simulations to provide a computational study of water and electrolyte systems. To increase the predictive accuracy of the TIP4P water model, a machine learning-guided reparameterization has been …
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ENZYME-LIKE DNA CATALYST DESIGN
… water. It first reviews the promise and limitations of DNA-based catalysis: although DNA offers chirality, structural programmability, aqueous compatibility, and sustainability, existing systems are often limited by difficult catalyst construction, narrow Lewis-acid-centered reaction scope, and …
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Development of Random Triblock Copolymer Based Nanoparticulate Formulation for Sustained Release of Macromolecules/Biologics in Treatment of Posterior Segment Ocular Diseases
… synthesized by ring opening copolymerization method. RTB copolymers are composed of FDA approved materials such as polyethylene glycol (PEG), glycolide (GA), lactide (LA) and ɛ-caprolactone (CL). RTB copolymers were synthesized and developed for sustained delivery of macromolecules to the …
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Quantification of Supramolecular Complexes Involving Charged Species in Non-Aqueous Solvents: Theory and Application
… broad equilibrium model describing the complexation of ionic species in non-aqueous media that explicitly includes ion pairing for one of the components and that relies upon activities rather than molar concentrations. This model directly contradicts existing commonplace equilibrium treatments, …
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Polysaccharide-based nanostructures for growth factor delivery and mesenchymal stem cell activation
… including bone and cartilage. MSCs differentiation can be modulated using both chemical (i.e. proteins) and physical cues (ie. topography). This thesis presents work performed evaluating polysaccharide-based nanostructures for growth factor delivery and MSCs activation. Different …
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Solvolysis of cobaltammines
The reactions studied were the aquaton of chloropentammine cobalt III chloride and the anation of aquopentanmine cobalt III ions with chloride ions in various e thanol—water rixtures. First order kinetics were observed for the aquation reaction being first order in cobalt concentration. The rate of …
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Labile Ligand Variation in Polyazine-Bridged Ruthenium/Rhodium Supramolecular Complexes Providing New Insight into Solar Hydrogen Production from Water
… for use as photocatalysts for the production of solar H2 fuel from H2O. The electrochemical, photophysical, and photochemical properties upon variation of the monodentate, labile ligands coordinated to the Rh reactive metal center were investigated. Bimetallic complexes …
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