Conjugated polymers (CPs) are often referred to as molecular wires because of their quasi one-dimensional electronic wavefunctions delocalized along the polymer chains. However, in the solid state, CPs tend to self-assemble through π-stacking, which greatly attenuates the one-dimensional nature. By molecular design, CPs can be molecularly insulated just like electric power cords, resulting in so-called “insulated” molecular wires (IMWs). In this Focus Review, we will discuss their unique photophysical, electronic, and mechanical properties which originate from the absence of π-stacking.

Far-from-equilibrium thermodynamic systems that are established as a consequence of coupled equilibria are the origin of the complex behavior of biological systems. Therefore, research in supramolecular chemistry has recently been shifting emphasis from a thermodynamic standpoint to a kinetic one; however, control over the complex kinetic processes is still in its infancy. Herein, we report our attempt to control the time evolution of supramolecular assembly in a process in which the supramolecular assembly transforms from a J-aggregate to an H-aggregate over time. The transformation proceeds through a delicate interplay of these two aggregation pathways. We have succeeded in modulating the energy landscape of the respective aggregates by a rational molecular design. On the basis of this understanding of the energy landscape, programming of the time evolution was achieved through adjusting the balance between the coupled equilibria.

All-polythiophene diblock copolymers, comprising one unsheathed block and one fenced block, were synthesized through catalyst-transfer polycondensation. The unsheathed block self-assembles through π-π stacking, thereby inducing microphase separation. Consequently, we have succeeded in creating a microphase separation comprising an ensemble of stacked and isolated polythiophenes. This achievement could be extended to various unexplored applications as a result of the integration of the contrasting functions of the two blocks.

Far-from-equilibrium thermodynamic systems that are established as a consequence of coupled equilibria are the origin of the complex behavior of biological systems. Therefore, research in supramolecular chemistry has recently been shifting emphasis from a thermodynamic standpoint to a kinetic one; however, control over the complex kinetic processes is still in its infancy. Herein, we report our attempt to control the time evolution of supramolecular assembly in a process in which the supramolecular assembly transforms from a J-aggregate to an H-aggregate over time. The transformation proceeds through a delicate interplay of these two aggregation pathways. We have succeeded in modulating the energy landscape of the respective aggregates by a rational molecular design. On the basis of this understanding of the energy landscape, programming of the time evolution was achieved through adjusting the balance between the coupled equilibria.

We report a new supramolecular rotor (1), in which a lanthanum(III) bis(porphyrinate)s double-decker (LaDD) bears two porphyrinatorhodium(III)-based rotors whose planes aresituated orthogonally to one another. In [D₂]dichloromethane, ¹H NMR spectral results indicated that rotational information was transmitted from the LaDD rotor to two porphyrinatorhodium(III)-based rotors through mechanical interaction of the teeth of the rotors. Mechanical interaction was achieved among the multiple rotors in 1 even after switching the rotational activity of the LaDD rotor by using [D₅]pyridine. The spatial arrangement of the two porphyrinatorhodium(III)-based rotors is a critical factor in maintaining mechanical interaction between multiple molecular rotors when changing the dynamic properties of one rotor.