Three distinct equilibrium states via self-assembly: simple access to a supramolecular ion-controlled NAND logic gate

During the past several decades, considerable effort has focused on self-assembled systems. However, most work has been directed toward understanding the equilibrium between two major chemical entities, namely the dissociated components and the corresponding associated complex. While there are quite a few examples of 'multiresponsive' materials, control over 'multistate' materials has proved difficult to achieve. Here, we report the formation and the interplay of a self-assembled calix[4]pyrrole array that exhibits three limiting forms, namely a 1:1 self-assembled oligomer, a 2:1 capsule, and the corresponding monomers. Interconversion between these states may be controlled by using the tetraethylammonium cation (TEA(+)) and/or iodide anion (I(-)) as chemical inputs. The combination of self-assembly and ion-based control may be used to create systems that display NAND logic behavior. The system outputs have been confirmed by a variety of analytic methods, including UV-vis and 2D (1)H DOSY, NOESY NMR spectroscopy, scanning electron microscopy, and single crystal X-ray diffraction analyses.