A New Class of Metal-Dependent Selective Anion Carrier. PH-Controlled Up-Hill Transport of SCN− by Formation of Transition-Metal Complex

Abstract

In the presence of appropriate pH-gradient across an organic liquid membrane, selective up-hill transport of SCN− through the membrane was efficiently mediated by 6,6′-bis(4-hexylbenzoylamino)-2,2′-bipyridine upon complex formation with CuII, in which the metal center served as an SCN−-selective binding site while pH-switched dissociation-association of the amide proton(s) of the ligand regulated uptake and release of SCN−.

Design of biofunctional molecular and supramolecular systems: Membrane transport models

“…In order to tune the hydrophobic nature of the carrier, n-hexyl groups are introduced to the parent complex. A novel complex-type carrier, Cu(lI) complexes of 6, 6'-bis(4-hexylbenzoylamino)-2, 2'-bipyridine (LH2) undergoes reversible step-wise deprotonation of the amide moieties through a mono-deprotonated complex, CuLH ÷, into a fully-deprotonated complex, CuL (Araki et al 1993a(Araki et al , 1996.…”