Tetrafluoroterephthalonitrile as an anion- donor: theoretical evaluation and application to anion recognition

The ability of perfluorinated terephthalonitrile to act as an anion-pi donor fragment in anion receptors is evaluated. New receptors combining an urea and a perfluorinated terephthalonitrile motif into a single architecture have been designed and synthesized. Their molecular recognition properties towards Cl-, Br- and I-, have been studied in solution by means of H-1 and F-19 NMR as well as photophysical experiments. A complementary electrospray ionization-tandem mass spectrometry study confirmed the ranking of recognition properties between the receptors. A further theoretical evaluation of binding properties confirmed the association constant trend and suggests a main contribution of the urea motif weakly complemented by a eta(2)-type anion-pi interaction.