Molecular design using electrostatic interactions. Part 1. Synthesis and properties of flexible tripodand tri- and hexa-cations with restricted conformations. Molecular selection of ferricyanide from ferrocyanide

Article abstract of DOI:10.1016/S0040-4020(97)10351-9

1,3,5-Tri- and hexa-cations derived from 1,3,5-tris(bromomethyl)-2,4,6- trimethylbenzene and DABCO or quinuclidine have been prepared and their interaction with polyanions in aqueous solution investigated by ¹H NMR titration and by isothermal titration calorimetry. The results from the two techniques are compared and the behaviour of these comparatively simple systems in water is shown to be complex. The trication 3b forms a crystalline precipitate with ferricyanide but not with ferrocyanide and can select for the one anion in the presence of the other. The structure of the ferricyanide salt 3e has been determined by X-ray crystallography.