Ionophoric properties of a tetra-tetrazole functionalised calix[4]arene

Abstract

The synthesis and characterisation of p-t-butylcalix[4]arene functionalised at the lower rim with four tetrazole moieties is reported. The macrocycle is found to be a poorer ionophore for lanthanoid cations than the bis-tetrazole–substituted analogue. Solution-phase photophysical studies strongly suggested that the cations interacted only weakly with the calixarene ligand. A mixed sodium/triethylammonium salt of the calixarene ligand was crystallised in the presence of lanthanoid cations and structurally characterised. Strong intramolecular interactions are hypothesised to be the cause of the observed behaviour.

Keywords:

• calixarene
• tetrazole
• lanthanide
• crystal structure

Acknowledgements

We acknowledge the use of the facilities and scientific and technical assistance of the Australian Microscopy and Microanalysis Research Facility at the Centre for Microscopy, Characterisation, and Analysis, The University of Western Australia, a facility funded by the University, State and Commonwealth Governments. D.D. gratefully acknowledges The Australian Institute of Nuclear Scientists and Engineers (AINSE), Ltd., for provision of a post-graduate research award (AINSE PGRA 2012).

Disclosure statement

No potential conflict of interest was reported by the authors.