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Title: Chiral hosts for enantioselective anion recognition
Author: Smyth, Megan Rebecca
ISNI:       0000 0004 6060 050X
Awarding Body: Queen's University Belfast
Current Institution: Queen's University Belfast
Date of Award: 2016
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This research thesis considers the synthesis of a novel library of symmetrical and unsymmetrical 2,2-bipyridine ligands containing both amide functionality and chirality. These ligands were then used to develop either a labile system containing iron(II) or an inert system comprised of ruthenium(II) complexes. The inclusion of chirality in the bipyridine ligand, from the synthesis with a chiral amine, resulted in a diastereomeric excess in the resulting metal complexes, observable using circular dichroism spectroscopy. Further enhancement of this diastereomeric excess was observed in the presence of particular anions. It was found that addition of certain anions would result in the degeneration of the iron(II) bipyridyl complex thus eliminating these anions as potential stimuli to perturb a dynamic iron(II) bipyridyl system. The stability of the iron(II) bipyridyl complex was also found to be affected by solvent, temperature and the counter anion. The use of chiral bipyridine ligands with ruthenium(II) afforded a mixture of isomers dependent on whether the ligand was mono- or difunctionalised. This thesis reports the separation of the ruthenium(II) complexes of unsymmetrical ligands in the respective isomers to afford enantiopure material. The anion binding properties were then studied using 1H NMR spectroscopic titrations with chloride anions. A ruthemum(II) bipyridine metal complex with non-chiral ligands was also synthesised and separated into the four isomers, first by preparative plate chromatography followed by cation-exchange chromatography* on Sephadex SP-C25 to obtain enantiopure material. These diastereomers were investigated using 1H NMR, UV/vis, emisson and CD spectroscopy, with the addition of the enantiopure chiral anion mandelate showing some potential diastereoselectivity.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available