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Host-Guest Chemistry: Physicochemical Aspects of Cyclodextrin-Drug and Lithium-Crown Ether Interactions.

Ng, Joe Cho Yan. (1995) Host-Guest Chemistry: Physicochemical Aspects of Cyclodextrin-Drug and Lithium-Crown Ether Interactions. Doctoral thesis, University of Surrey (United Kingdom)..

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Abstract

This thesis reports investigations related to the interactions between a) cyclodextrins and cephalosporins and b) crown ethers and lithium salts in solvents currently used in battery technology. As far as cyclodextrins are concerned, their thermodynamics of complexation with cephalosporins in water reveal that α-cyclodextrin shows no selective complexation with these drugs (enthalpy-entropy compensation effect) while β-cyclodextrin only interacts with sodium cefuroxime. No interactions between γ-cyclodextrin and these drugs are observed. These thermodynamic findings are corroborated by 1H NMR studies, leading to the conclusion that the host cavity size plays an important role in the binding of cyclodextrins with these drugs in water. As far as crown ethers (12 crown 4 and 1-benzyl-1-aza-12 crown 4) are concerned, the thermodynamics of complexation derived from titration microcalorimetry reflect that in acetonitrile and in propylene carbonate, the stabilities of lithium-crown ether complexes are high enough as to proceed with their isolation. Thus, eight lithium coronand salts were isolated. The thermochemical behaviour of these new electrolytes, the lithium salts and the crown ethers in acetonitrile and in propylene carbonate show that lithium coronands are less solvated than common lithium salts in these solvents. The implication of these findings on the conductivity enhancement of the former relative to the latter is demonstrated. Thus, ionic conductivities of lithium coronand cations are higher than corresponding data for the free cation in propylene carbonate, an important aspect to consider in lithium batteries. These studies stress the importance of fundamental thermodynamics in the selection of electrolytes which show promise in battery technology. Finally, enthalpies of coordination (referred to reactants and products in their pure physical states) derived from complexation and solution data show the effect of the anion in the coordination process.

Item Type: Thesis (Doctoral)
Divisions : Theses
Authors : Ng, Joe Cho Yan.
Date : 1995
Additional Information : Thesis (Ph.D.)--University of Surrey (United Kingdom), 1995.
Depositing User : EPrints Services
Date Deposited : 06 May 2020 14:15
Last Modified : 06 May 2020 14:20
URI: http://epubs.surrey.ac.uk/id/eprint/856124

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