RESUMO
Doping of the ferroelectric Sm-C(*) phase with bent-shaped molecules induces the antiferroelectric Sm-C(*)(A) phase. The effect was observed by means of electro-optic and dielectric measurements in systems with weak interlayer interactions in which the relative strength of anticlinic-synclinic order between molecules in adjacent layers is easily controlled by external factors. Fourier-transform infrared spectroscopy studies suggest that the bent-shaped molecules are not flat. They reorient upon the electric field-induced antiferroelectric-ferroelectric transition to adopt a position in which the average direction of the carbonyl groups is in the smectic plane and a bending tip along the C2 symmetry axis.
RESUMO
Sequential polymerization of supramolecular metallorotaxane complexes results in three-stranded conducting ladder polymers. The internal polymer is "sandwiched" between the other two polymers to give molecular wires that are effectively insulated when the outer polymers are in their nonconducting state (shown schematically). The intermolecular conductivity can be mediated by the Cu(1+)/Cu(2+) redox couple.