Self-Assembly of Calix[4]Arene Amine Derivatives

A new family of calix[4]arene amine derivatives, which have been functionalised on both the upper and lower rim have been developed as potential duel metal ion binding complexes, and all were fully characterised. The lower rim was first functionalised with various groups such as benzyls and pyridyls to give stability to the calix[4]arene unit, followed by functionalisation of the upper rim with an amine, such as 2-(aminomethyl)pyridine, and/or a bipyridine moiety. The derivatives were tested with a wide range of metal salts, MX2, (M = Zn2+, Cu2+, Ni2+, Hg2+, Co2+ and X = acetate, chloride, perchlorate). During the course of this project it was noted that the 1H NMR spectra were much more complex than had been expected. To this end a series of nOe, serial dilution, high temperature and HMBC NMR spectroscopic techniques were employed. The results of these revealed that self-assembly was occurring in solution and it is believed that two kinds of self-assembled structures are present, namely the heterodimerisation form and the homodimerisation form. It is believed that due to the loss of the t-butyl groups early in the synthesis that this allows extra flexibility in the calix[4]arene unit, thereby allowing it to alternate between its different conformers. Metal ion complexation was performed to try and control the self-assembly but to no avail. Fluorescence studies were performed on several compounds to further examine the metal-ligand interactions. It was found that with the addition of the metal ions intensity had an overall increase in intensity and the fluorescence bands were blue-shifted with respect to the parent compound fluorescence bands. Unfortunately suitable crystals were not obtained for X-ray analysis. SEM was performed on several of the compounds and their corresponding metal complexes and the images obtained give some insight into the morphology of the structures.

Name dc:type.qualificationname

phd

Level dc:type.qualificationlevel

doctoral

Grantor dc:publisher.institution

National University of Ireland Maynooth

Year dc:date.issued

2013

Author dc:creator

• O'Toole, Laura

• Chemistry

Language dc:language

en