Table of Contents
Metal-Based Drugs
Volume 1 (1994), Issue 2-3, Pages 151-160

Transition Metal Ion Complexation and Extraction by Hydroxamate Functionalised p-Tert-Butylcalix[4]Arenes

1Chemistry Department, University College Cork, Ireland
2School of Chemistry, The Queen's University of Belfast, Ireland
3Dublin City University, Ireland

Received 2 September 1993

Copyright © 1994 Hindawi Publishing Corporation. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


The functionalisation of macrocyclic p-tertbutylcalix[4]arenes at the lower rim with hydroxamic acid and proline hydroxamic acid groups gives the calixarenes chelating properties similar to siderophores. The H1 NMR spectrum of p-tertbutylcalix[4]arene tetrahydroxamic acid shows a broad band at 10.8 ppm in DMSO-d6 attributed to NHOH protons. Diffuse reflectance spectral analysis of PVC membranes containing the calixarene hydroxamic acids show absorption bands at 485 nm and 504 nm following contact with aqueous solutions of Fe(III) and V(V) respectively. The pH dependency of this extractive selectivity is examined for Fe(III), Co(II), Pb(II), Mn(II), Cu(II) and Ni(II) using a solid phase extraction approach. Spectrophotometric evidence for the complexation of Cu(II) in methanol by p-tertbutylcalix[4]arene tetraproline acid is also provided.