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Title: Application of optically pure chiral anionic complexes in the construction of molecular conductors
Author: Chmel, Nikola Paul
ISNI:       0000 0004 2705 9707
Awarding Body: University of Warwick
Current Institution: University of Warwick
Date of Award: 2010
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Chapter 1 introduces the phenomenon of Magnetic Chiral Anisotropy in chiral conductors and reviews the current literature on chiral charge transfer molecular conductors and synthetic routes towards them. The second part of the chapter focuses on examples of chiral anionic species reported in the literature. Chapter 2 describes the synthesis and improvements to the literature procedures for organic donor molecules: tetrathiafulvalene, tetraselenafulvalene and bis(ethylenedithio)tetraselenafulvalene. The synthesis and characterisation of new chiral TTF imine systems are also reported. A stable TTF imine derivative of chiral biphenyl amine was used in the synthesis of a homochiral bimetallic helicate with copper(I). Unusual structural and magnetic properties of this compound are reported. Chapter 3 focuses on the synthesis and properties of optically pure anionic complexes, [MIII(Ln)2]-(M = Co, Fe), of chiral pyridinecarboxamide ligands (Ln). The complexes show interesting extended structures ranging from 0D discrete units through 1D zigzag chains to 2D honeycomb layers. The complex anions were used in the synthesis of radical cation salts with tetrathiafulvalene (TTF). The salts (TTF)[CoIII(R,R-L1)2] and (TTF)[CoIII(S,S-L2)2]·EtOAc were characterised by single crystal X-ray diffraction and conductivity measurements. Solution spectroscopic and cyclic voltammetric evidence points to the formation of soluble assemblies between TTF+ and the counterion which correspond to the stoichiometry observed by crystallography and other methods in the solid state. Chapter 4 describes the synthesis of the first diastereomerically pure, organicsoluble salts of cobalt, iron and chromium complexes of optically pure chelate: H4EDDS. A number of synthetic approaches were attempted, but finally the PPh4[MIII(EDDS)]·2H2O series emerged providing readily accessible compounds in reasonable yields via the silver salts. The species are very soluble in methanol, acetonitrile and even THF and isolation of highly crystalline solids is possible upon addition of water. The structures of the three compounds are isomorphous and comprise of H2O-bridged extended hydrogen bonded structures with large channels occupied by the counterion molecules. The magnetic properties and circular dichroism spectra are reported. The diastereomeric purity in the paramagnetic systems is assessed through powder XRD. Chapter 5 focuses on the use of organic-soluble EDDS complexes in the resolution of optically active cations and as a chiral NMR shift agent. The initial results of the resolution of (±)-[RuII(bpy)3]2+ are reported along with the crystal structure of the {Λ-[RuII(bpy)3]}{Λ-[FeIII(S,S-EDDS)]}Cl·H2O adduct. The result of testing of the diamagnetic PPh4[CoIII(S,S-EDDS)] salt as·a 1H NMR shift agent for chiral complex cations: [ML3]2+, (M = Co, Ru, Fe; L = bpy, phen, en) and small organic molecules are also reported. Chapter 6 describes the electrochemical synthesis of a new family of conductive optically pure tetrathiafulvalenium and tetraselenafulvalenium salts D3[MIII(S,S-EDDS)]2·nH2O (where D = TTF, TSF; M = Co, Fe, Cr). The compounds are characterised by single crystal X-ray diffraction, conductivity measurements and elemental microanalysis and exhibit well-behaved semiconductor behaviour with conductivities up to 2.8·10-4 S·cm-1 (Ea ca 0.1 eV). Computational work indicates that it is feasible to generate metallic conductors with similar structures. Initial results for an ET analogue showing metallic conductivity are also reported. Chapter 7 details the experimental procedures used to carry out the work in this thesis.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available
Keywords: QD Chemistry