Abstract
Currently, the discharge of pollutants to the environment is considered one of the biggest problems challenging chemists and environmental scientists. These pollutants come from different sources and might be carcinogenic, toxic or radioactive compounds which can cause serious health hazards to humans, animals and plants. Intensive thermodynamic studies by Danil de Namor and co-workers in the Thermochemistry Laboratory indicated that functionalisation of calix[4]pyrroles, cyclodextrines and calix[n]arenes ( n=4,6 ) leads to the production of selective macrocyclic receptors for the removal of anions, toxic heavy metals and other pollutants from water. The objective of this thesis is to design, synthesise and characterise macrocyclic receptors with suitable functional groups for the selective removal of drugs and anions from water. The drugs selected for this study are diclofenac, sodium diclofenac, clofibric acid, carbamazepine, aspirin and ibuprofen. This selection is based on the fact that these drugs are extensively used and as a result these contaminate sewage, surface and ground water. Supramolecular chemistry is one of the most important areas of chemistry which offers many advantages due to the efficient, fast and economical way for removing pollutants from water. In this thesis a large number of macrocycles based on calix[4]arene, calix[4]pyrrole resorc[4]arene and pyrogalol[4]arene have been synthesised and characterised by 1H NMR and microanalysis. From these receptors those based on cyclodextrin and calix[4]arene derivatives have been selected for sodium diclofenac while for drugs containing carboxylic acids in their structure, a partially substituted calix[4]arene amine was selected for further investigations involving these drugs. These interactions were assessed in solution by several techniques such as 1H NMR titration, UV-Visible, conductivity, isothermal titration calorimetry. In the solid state, thermogravimetry and differential scanning calorimetry were explored. The extraction of these pharmaceuticals by some of these macrocycles under different conditions is reported. The importance of fundamental studies in searching for applications is demonstrated where the selectivity of the calix[4]arene amine for these drugs is shown in the extraction process. Modified silica with amino functional groups is explored for extracting aspirin from water. Preliminary research on the efficiency of pyrogallol[4]arene and resorcine[4]arene to work as molecular containers for selected drugs were tested by 1H NMR Two novel calix[4]pyrroles were investigated for complexation with halides and phosphates showing their selectivity for phosphates relative to halides. Final conclusions are given as well as suggestions for further work particularly with the new oligomeric material which has been characterised by various techniques which are FTIR, XRD, SEM, BET analysis