Anion recognition and anion-mediated self-assembly with thiourea-functionalised fused [3]polynorbornyl frameworks.
Three conformationally preorganised host molecules based on the [3]polynorbornyl framework and incorporating di-urea receptors were synthesised and their interaction with a series of anions investigated by (1)H NMR spectroscopy. A high affinity of each host molecule for dihydrogenphosphate (H(2)PO(4)(-)) and dihydrogenpyrophosphate (H(2)P(2)O(7)(2-)) was identified. In addition to binding to the urea receptors of the host molecules, evidence for an interaction involving the non-polar C-H groups within the binding cavity of the framework and guest anions was also discovered. Furthermore, an unusual 2 : 1 host-to-anion stoichiometry was indicated when binding H(2)P(2)O(7)(2-), and a model for the anion-mediated self-assembly of this complex species is proposed.
Pfeffer
Frederick M
FM
School of Life and Environmental Sciences, Deakin University, Waurn Ponds, Australia. thefef@deakin.edu.au
Kruger
Paul E
PE
Gunnlaugsson
Thorfinnur
T