Cation binding, transport and theoretical calculations of cone-p-tert-butylhexahomotrioxacalix[3]arene tris(acetic acid)

Griffiths, Kieran and Sharma, Kushal and Marcos, Paula M. and Ascenso, José R. and Nind, Jade and Cottet, Kevin and Cragg, Peter J. (2015) Cation binding, transport and theoretical calculations of cone-p-tert-butylhexahomotrioxacalix[3]arene tris(acetic acid). Supramolecular Chemistry, 27 (3). pp. 167-173. ISSN 1061-0278

Abstract

The metal cation binding ability of cone-p-tert-butylhexahomotrioxacalix[3]arene tris(acetic acid) was investigated by 1H NMR and complementary semi-empirical calculations. NMR showed significant shifts with Na+, K+, Ag+ and, to a lesser extent, Pb2+. The macrocyclic protons undergoing the greatest shifts imply that these cations bind inside the cavity composed of the phenoxy and carbonyl oxygen atoms. Metal complexes were modelled using a semi-empirical approach and, in general, their geometry optimised structures were in agreement with NMR data. U-tube transport experiments demonstrated that the macrocycle actively transported Cr3+, Fe3+, Co2+ and Cu2+ through the organic phase.