Abstract
A brief description of Supramolecular Chemistry, followed by a literature review on the chemistry of calix[n]arene derivatives (n = 4-6) concerning the work carried out in this thesis are included in the Introduction Section. A fully detailed investigation on structural and thermodynamic aspects of calix[n]arene amide derivatives (n= 4-6) with metal cations (alkali, alkaline earth, transition and heavy metal cations) were carried out in different media at 298.15 K. The information were obtained using the appropriate techniques and The successful syntheses of 5,11,17,23-tetra-(1,1-dimethylethyl)-25,26,27,28-tetra-{N,N-diethylamide)-ethoxy-calix[4]arene (L1), 5,11,17,23,29 penta-tert-butyl 31,32,33,35-penta hydroxyl calix[5]arene (L2) and 5,11,17,23,29,35-p-tert-butyl-37,38,39,40,41,42- hexadiethylacetamide-calix[6]arene (L3) was confirmed by 1H NMR and elemental analysis. The solution thermodynamics for L1 and L3 were investigated and the degree of solvation of these macrocycles on different media relative to acetonitrile was derived from the ?tG°(s1-s2) from one solvent relative to acetonitrile 1H NMR studies for L1 in different media at 298 K gave valuable information on the conformation that this ligand adopts in these solvents. The interaction of L1 with metal cations in deuterated solvents was analysed by 1H NMR at 298 K. Information on the binding sites was also obtained from these experiments. Conductometric titrations in acetonitrile and methanol at 298.15 K were performed to establish the stoichiometry of complex formation for L1 and L3 with metal cations. This was followed by calorimetric and potentiometric titrations with metal cations at 298.15 K to determine the thermodynamic parameters of complexation. The medium effect on the complexation processes was assessed for L1 and monovalent metal cations in one solvent relative to another at 298.15 K. This was investigated taking into account the thermodynamic parameters of transfer of the reactants and the product from acetonitrile relative to methanol. A comparative study involving the three ligands was discussed on the basis of the experimental data obtained for each of these macrocycles in their complexation with metal cations. Conclusions and suggestions for further investigations are given.