Chirality induction by formation of assembled structures based on anion-responsive π-conjugated molecules.

Anion-responsive π-conjugated compounds having chiral alkyl chains were synthesized. Circular dichroism (CD) and circularly polarized luminescence (CPL) were observed in the solution-state assemblies of the chiral anion receptors and those of their anion complexes as salts of a planar triazatriangulenium cation. The CD and CPL spectral patterns of the ion-pair-based assemblies were completely opposite to those of the anion-free assemblies, and this suggests that anion binding and subsequent ion pairing change the chirality of the assembly modes.

Ion-based materials of boron-modified dipyrrolyldiketones as anion receptors.

Boron-modified pyrrole-based anion receptors (catechol-boron and diphenylboron dipyrrolyldiketone derivatives) formed planar receptor-anion complexes, leading to charge-by-charge assemblies with planar cations, as in the corresponding difluoroboron derivative.

Charge-based assemblies comprising planar receptor-anion complexes with bulky alkylammonium cations.

Charge-by-charge assembly: On the basis of a planar receptor-anion complex, bulky tetraalkylammonium cations were found to construct charge-by-charge assemblies comprising alternately stacked positively and negatively charged species. The number and length of long alkyl chains in the cations determine the states of assembled structures, resulting in the formation of a library of charge-based materials (see scheme).

Solvent-dependent supramolecular assemblies of π-conjugated anion-responsive acyclic oligopyrroles.

Amide-attached pyrrole-based π-conjugated anion receptors showed solvent-dependent assembled modes such as H-aggregates that were soluble in octane and highly organized structures that provided supramolecular gels in CH(2)Cl(2) and 1,4-dioxane in the absence of π-π stacking.

Discotic columnar mesophases derived from 'rod-like'pi-conjugated anion-responsive acyclic oligopyrroles.

Rod-like pi-conjugated anion-responsive acyclic oligopyrroles have been reported to form stacked disk-like components that result in the formation of discotic columnar mesophases as thermotropic liquid crystals.