Pyridinium CH center dot center dot center dot anion and pi-stacking interactions in modular tripodal anion binding hosts: ATP binding and solid-state chiral induction

The preparation of two new tripodal 'pinwheel' type anion hosts based on a triethylbenzene core and bipyridinium or ethylnicotinium arms is reported. The new materials bind anions via CH center dot center dot center dot anion interactions. Complexes with Br- and PF6- have been characterised by X-ray crystallography as both solvates in a pure form. In the bipyridinium host CH center dot center dot center dot F interactions to PF6- induce a chiral C-3 symmetric conformation that is disrupted in the hydrate. The compound is also selective for ATP(2-) in aqueous acetonitrile.