Following an introduction on calixarene chemistry and their metal-ion complexes including some of their applications, the aims of the work are described. Thus, this thesis concerns an investigation on the solution properties of p-tert-butylcalix(4)arene tetraketone derivatives and their metal-ion complexes. Macrocycles such as 5,11,17,23-tetra-terf-butyl-25,26,27,28-tetra(benzoyl)methoxycalix(4)arene and 5,11,17,23-tetra-tert-butyl-25,26,27,28-tetra(acetoyl)methoxy calix(4) arene are structurally (1H NMR and X-ray crystallography) and thermodynamically (solubility, calorimetry) characterised. The complexing abilities of these ligands for metal cations are investigated by a variety of techniques. To obtain information about the active sites of the ligand in its interaction with metal cations, 1H NMR studies were performed. Conductance and UV spectrophotometric measurements were used to establish the composition of the metal-ion complexes in dipolar aprotic media. Potentiometric and calorimetric measurements were carried out to derive the thermodynamic parameters of complexation of p-tert-butylcalix(4)arene tetramethyl ketone and metal-ions in acetonitrile at 298.15 K. This ligand shows the highest affinity for calcium amongst all the investigated metal cations. The medium effect on the complexation process involving metal cations and calixarene derivatives is quantitatively assessed using as an illustrative example the interaction of p-terf-butylcalix(4)arene tetraphenyl ketone and the sodium cation. Thus, detailed thermodynamics of this system is reported taking into account the solution properties of the reactants and the product in various solvents and in acetonitrile / N,N- dimethylformamide solvent mixtures. In these mixtures a linear relationship is observed between the stability constant and the solvent composition. The strength of complexation decreases from MeCN through the mixtures to pure DMF. However in terms of the enthalpy of complexation, only small variations are found between the values in different mixtures. The complexation and solution data for the reactants and the product are used to calculate the standard co-ordination enthalpies as a means of checking the reliability of the data. Based on stability constant data, two metal-ion complexes were isolated. X-ray diffraction data shows that p-tert-butylcalix(4)arene tetraphenyl ketone hosts the sodium cation in its hydrophilic cavity where it is coordinated by four ethereal oxygen atoms and four carbonyl oxygen atoms. One molecule of acetonitrile is found in the hydrophobic cavity of the ligand with the CH3 end pointing inward. The crystal structure of the cadmium and acetonitrile p-tert-butylcalix(4)arene tetramethyl ketone complex shows that the metal ion is coordinated by four ethereal oxygen atoms of the ligand and only by three carbonyl oxygens. The eight coordination site is provided by the nitrogen atom of the molecule of acetonitrile which is present in the hydrophobic cavity of calixarene derivative with the CN end pointing inward. Conclusions and suggestions for further research in this area are given.

This thesis presents investigations related to interactions of chelating ligands (macrocyclic and acyclic) with neutral and ionic species in solution. Following a brief introduction on coordination chemistry, each topic is presented separately in three chapters. In Chapter I, thermodynamic studies on drug cyclodextrin interactions in water and in chloroform at 298.15 K are discussed in relation to the effect of the macrocycle on the transfer of N1-substituted sulphonamides from water to chloroform. It is concluded that the transfer of the drug in this solvent system is thermodynamically more favoured in the absence than in the presence of cyclodextrin. Chapter II concerns thermodynamic aspects on calixarenes and their ester derivatives. As far as calixarenes are concerned, thermodynamic parameters of complexation of tert-butylamine and p-tert-butylcalix[4]arene in benzonitrile suggest that two processes are involved; the formation of the adduct followed by that of an endo-calix complex. The interaction of alkyl-p-tert-butylcalix[4]arene tetraethanoates with alkali-metal cations in acetonitrile and in benzonitrile at 298.15 K was studied by titration calorimetry. The limitation of this technique to derive stability constant data for highly stable complexes led to the development of a double competitive potentiometric method. Thermodynamic data are discussed in terms of the solvation of host, guest and resulting complex in these solvents. Chapter III discusses synthesis, characterisation and acid-base properties of ethylenedinitrilo-N,N1-diacetic-N,N1-bis(1-phenylethylacetamido) acid (edtamba) and ethylenedinitrilo-N,N1-diacetic-N,N'bis(pyridylacetamidoacetamioe)acid (edtapa) This is followed by the thermodynamics of complexation of these ligands with metal cations (Pb(II), Cd(II), Cu(II), Ni(II), Zn(II) and Co(II) in water at 298.15 K. These results show that unlike EDTA, edtamba and edtapa do not interact selectively with these cations as a result of a remarkable enthalpy-entropy compensation effect. Computer programs written during the course of these investigations are appended.

Following an overview in the field of calixarene chemistry given in the introduction, this thesis reports, i) The synthesis of p-text-butylcalix[4]arene tetraacetamides, thiophosphates and derivatives containing mixed functional groups and the characterisation by IR, NMR and microanalysis. ii) The solution thermodynamic of p-tert-butylcalix[4]arene tetradiisopropylacetamide and the transfer thermodynamics of this ligand from acetonitrile to various solvents. iii) Spectrophotometric, potentiometric and calorimetric studies on the interaction of p-tert-butylcalix[4]arene tetraacetamides and metal cations in butan-l-ol and in water saturated butan-l-ol at 298.15 K. Metal-ion complexes of p-tert-butylcalix[4]arene tetradiisopropylacetamide were isolated and characterised by IR, NMR and spectroscopy and microanalysis. In butan-l-ol, the selectivity of this ligand for metal cations follows the sequence Na+ > Cd2+ > Pb2+ > Zn2+ > Ag+. However, this sequence is altered in the water saturated solvent to an extent that the strong complexation observed for this ligand and zinc(II) in butan-l-ol is non-existent in the water saturated solvent. Using complexation data in conjunction with solution data of the host, the guest and the resulting complex, enthalpies of coordination (referred to the process which reactants and the product in the solid state) were calculated. iv) Extraction experiments in the water-butan-l-ol solvent system at 298.15 K in the presence of p-tert-butylcalix[4]arene tetradiisopropylacetamide were performed. The higher extraction of lead(II) relative to other metal cations from the aqueous solution to the organic phase in the presence of the ligand at low hydrogen-ion concentration is demonstrated. The extraction of radioactive lead(II) by the same ligand was investigated as a function of i) the pH of the aqueous phase ii) the ligand concentration in the organic phase. vi) A new polymeric material was obtained by attaching the ligand to the polymer. Final conclusions are drawn and suggestions for further work in this area are given.

No description available.

[Truncated abstract] The scientific endeavours described within this thesis attempt to create novel solutions to current scientific, commercial and industrial downfalls, and contribute to the advancement of technologies in these areas. This has been achieved through the application of theoretical and experimental principles, entrenched in the domains of chemistry and physics, which have been harnessed to assist in the transformation from nanoscience to nanotechnology. These solutions range from unique supramolecular systems capable of selective-diameter enrichment of single-walled carbon nanotubes (SWCNTs), to the fabrication of low-cost, potentially remote deployable carbon nanotube-based gas and vapour sensors, and expand right through to the development of water-soluble fluoroionophoric sensors and manipulations of a molecular form of carbon in constructing all-carbon nano-architectures. For the advancement and successful integration of carbon nanotubes (CNTs) into commercial processes, the advent of scalable separation protocols based on their electronic properties is required. SWCNTs have been successfully solubilised using water-soluble p-phosphonated calix[n]arenes (n = 4, 6, 8) and 'extended arm' upper rim functionalised (benzyl, phenyl) p-sulfonated calix[8]arenes. Selective SWCNT diameter solubilisation has been demonstrated and subsequent preferential enrichment of SWCNTs with semiconducting or metallic electronic properties has been achieved. In addition, semiconducting nanotube-enriched supernatants (liquid) have been utilised to fabricate on/off field effect transistors (FET). These water-soluble supramolecular systems can be incorporated into post-growth purification protocols, with direct implications in areas such as carbon nano-electronics and device fabrication. In the current global environment there is a heightened level of public and governmental disquiet due to the reality of impending terrorist attacks. This is compounded by the inherent ease of manufacture and effectiveness of specific chemical warfare agents (CWAs) used in small-scale terrorist operations. ... Additional all-carbon structures are described with the formation of rings of helical SWCNT bundles through post-growth SWCNT modifications, and a variety of fibrous all-carbon structures, most notably novel square-geometry carbon nano-fibres (CNFs), through catalytic-chemical vapour deposition (C-CVD) synthesis strategies. The current requirement for entirely water-soluble fluorescent sensors is routinely documented in the literature. The autofluorescence properties of p-phenyl-sulfonated calix[8]arene are characterised and this water-soluble cavitand is surveyed as a metal cation sensor candidate. This particular system was found to exhibit a change in fluorescence response when exposed to divalent metal cations, and interactions with [UO2]2+, Pb2+, Co2+, and Cu2+ ions are discussed in detail. The system is characterised through a variety of analytical techniques to yield sensor calibration data, degradation characteristics, pH sensitivity and suitability as a 'small molecule' drug-carrier.