Shall we twist? Three-dimensional arrangement of π-conjugated chromophores with triple-stranded helicity was achieved by using the planar chirality of m-calix[3]amide. Based on spectroscopic data and theoretical calculations, the dynamic and preferred helical characters of bithiophene units embedded in the tubular molecule were elucidated, and the absolute configuration was determined.

Solution acyclic diene metathesis (ADMET) polymerization using Grubbs' fi rst-generation catalyst leads to the direct synthesis of polymers containing hydroxyl groups. Secondary alcohols are placed precisely at specifi c intervals on an unsaturated hydrocarbon backbone. Increasing the number of methylene spacers decreases the frequency of the pendant groups from every 15th carbon to every 21st carbon. The complete hydrogenation of the unsaturated polymers yields model representatives of well-defi ned ethylene-vinyl alcohol copolymers. Despite the decrease in branch frequency in both the homopolymers and randomized versions of such polymers, surprisingly, the precision does not have an infl uence on the thermal properties, and they are all similar in nature. It is concluded that hydrogen bonding dominates the polymer behavior, rather than the precision in hydroxyl-group placement along the polyethylene chain.

Interactions between designed charged species are important for the ordered arrangements of π-electron systems in assembled structures. As precursors of π-electron anion units, new arylethynyl-substituted dipyrrolyldiketone boron complexes, which showed anion-responsive behavior, were synthesized. They formed a variety of receptor-anion complexes ([1+1] and [2+1] types) in solution, and the stabilities of these complexes were discussed in terms of their thermodynamic parameters. Solid-state ion-pairing assemblies of [1+1]- and [2+1]-type complexes with countercations were also revealed by single-crystal X-ray analysis. In particular, a totally charge-segregated assembly was constructed based on negatively and positively charged layers fabricated from [2+1]-type receptor-anion complexes and tetrabutylammonium cations, respectively. Furthermore, the [1+1]-type anion complex of the receptor possessing long alkyl chains exhibited mesophases based on columnar assembled structures with contributions from charge-by-charge and charge-segregated arrangements, which exhibited charge-carrier transporting properties.

As fascinating examples of closely connected multiple π-electronic systems involving noncovalent interactions, the cooperatively interlocked [2+1]-type anion complexes of well-designed π-electronic molecules are reported. The anion-responsive π-electronic molecules investigated in this study are the boron complexes of dipyrrolyldiketones bearing arylethynyl moieties at the pyrrole α-positions. Diverse substituents were introduced at the terminal aryl moieties, thus controlling the cooperativity to form [2+1]-type complexes. Theoretical studies showed that this cooperativity was induced by effective interactions between the introduced arylethynyl moieties. The investigations of the anion-binding processes showed that the first and second bindings to the guest anion were energetically almost equivalent, indicating the fundamental and important features of the electronic states of the halide anions. Furthermore, the interlocked anion complexes, whose geometries were distorted from the orthogonal arrangements, had the racemic states of the chiral conformations, either of which was induced by ion pairing with an appropriate chiral π-electronic cation, resulting in the chiroptical property as shown by circular dichroism.