Synthesis of dendrimeric pyrrole derivatives

The aim of the project was to chemically synthesise and investigate the structure properties of a series of first, second and third generation dendrimers with a polypyrrole core, from which only the first and second generation dendrimers were synthesized. The synthesis was carried out using a combination of divergent and convergent strategies, utilizing S[sub]N2 Williamson ether synthesis. Purification was done by either vacuum distillation or column chromatography using silica gel a stationary phase and a combination of solvents for the mobile phase. Attempts were made to polymerize the dendrimers via chemical oxidation of the pyrrole unit, using iron (III0 chloride. The majority of the third generation dendrimer was synthesized. Characterisation of the first and second generation dendrimers also the intermediate molecules used to synthesize them were carried out by Infra Red spectroscopy (IR), Gas Chromatography-Mass Spectroscopy (GC-MS), Liquid Chromatography-Mass Spectroscopy (LC-MS), H[sup]1 NMR, C[sup]13 NMR and Ultra-violet spectroscopy (UV). The spectral data have been used in comparison to previously documented analogues. Most of these techniques were successful with the monomers and intermediates; however difficulties were encountered when characterising the dendrimers, and it was concluded that in future oxidative polymerisation of the pyrrole dendrimers using an electrochemical method would cause fewer complications in the purification process. Conductivity measurements were also carried out for the un-doped polymers, which were found to be semi conductive.