Premium
Cooperative AND Ion‐Pair Recognition by Heteroditopic Calix[4]diquinone Receptors
Author(s) -
Lankshear Michael D.,
Dudley Ian M.,
Chan KarMan,
Cowley Andrew R.,
Santos Sérgio M.,
Felix Vitor,
Beer Paul D.
Publication year - 2008
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.200701347
Subject(s) - receptor , ion , chemistry , folding (dsp implementation) , stacking , crystallography , biophysics , molecular recognition , ion channel , stereochemistry , molecule , biochemistry , biology , organic chemistry , electrical engineering , engineering
A new family of heteroditopic calix[4]diquinone receptors capable of the cooperative recognition of ion‐pair species through a contact binding mechanism has been developed. The receptors bind contact ion pairs cooperatively, with an unprecedented AND recognition phenomenon being observed to operate in certain cases, in which receptors display no affinity for either of the individual “free” cation or anion, but bind the cation and anion ion‐pair strongly. X‐ray crystallographic, solution‐state, and computational methods rationalize the observed recognition behavior of the receptors. It is shown that the contact ion‐pair interaction occurs through a π‐stacking‐mediated folding of the receptors such that the anion and cation binding sites are arranged in close proximity, while in the solid state an unusual ion‐mediated receptor dimerization is observed. Molecular dynamics simulations are further used to explain the observed trends in the association constants of different ion‐pair species and the mechanism of interaction.