MOLECULAR DESIGN USING ELECTROSTATIC INTERACTIONS - 1 - SYNTHESIS ANDPROPERTIES OF FLEXIBLE TRIPODAND TRI-CATIONS AND HEXA-CATIONS WITH RESTRICTED CONFORMATIONS - MOLECULAR-SELECTION OF FERRICYANIDE FROM FERROCYANIDE

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 the ir interaction with polyanions in aqueous solution investigated by H-1 NMR titration and by isothermal titration calorimetry. The results fr om the two techniques are compared and the behaviour of these comparat ively simple systems in water is shown to be complex. The trication 3b forms a crystalline precipitate with ferricyanide but not with ferroc yanide 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 (C) 1997 Elsevier Science Ltd. All rights reserved.