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Structural changes in the guest cause inversion of the dominant threading direction in triptycene derived oxacalixarene with different semi-cavities., The manipulation of supramolecular devices to carry out sophisticated and programmed tasks is bound up with the spatial allocation of their components, especially the threading direction of the guest, which controls the host–guest orientation in the device. However, insights are needed to probe more possibilities for steering the threading direction. We have developed a new system consisting of a three-dimensional nonsymmetric oxacalixarene (H) with a fixed comformation and (bi)pyridinium salts (G1–G3), in which we found that based on the intrinsic discrepancies between the two semi-cavities of H, the electron densities of the axles greatly affect the threading direction. This was unequivocally demonstrated by NMR spectra and single crystal structures. With elaborate design, unidirectional threading was achieved, resulting in an oriented rotaxane. Therefore, we describe a new approach in which the threading direction and final orientation may be finely controlled by adjustment of the structure of the guest.

Sandwiched electrical devices of an electropolymerized diruthenium metallopolymeric film show excellent resistive memory switching., A diruthenium complex capped with two triphenylamine units was polymerized by electrochemical oxidation to afford metallopolymeric films with alternating diruthenium and tetraphenylbenzidine structures. The obtained thin films feature rich redox processes associated with the reduction of the bridging ligands (tetra(pyrid-2-yl)pyrazine) and the oxidation of the tetraphenylbenzidine and diruthenium segments. The sandwiched ITO/polymer film/Al electrical devices show excellent resistive memory switching with a low operational voltage, large ON/OFF current ratio (100–1000), good stability (500 cycles tested), and long retention time. In stark contrast, devices with polymeric films of a related monoruthenium complex show poor memory performance. The mechanism of the field-induced conductivity of the diruthenium polymer film is rationalized by the formation of a charge transfer state, as supported by DFT calculations.