Energies and selectivities for anion binding as a function of host conformational preorganisationElectronic supplementary information (ESI) available: NMR data and binding isotherms. See http://www.rsc.org/suppdata/cc/b2/b200605g/

The anion binding of tripodal hosts 2-4 has been studied. Increasing levels of conformational preorganisation of the side arms of the hosts led to increased (Cl-) unaltered (Br-) or decreased (NO3-) binding; it was thus possible to change guest selectivities by about an order of magnitude through conformational preorganisation of the flexible host.