Supramolecularly Engineered Functional π-Assemblies Based on Complementary Hydrogen-Bonding Interactions

As details of exciting photonic and electronic properties arising from self-assembled functional dyes and related pi-conjugated molecules become clearer, strategies for control of short and long-range chromophore chromophore orientations, regulation of pi-pi stacking arrangements, construction of self-organized nano-to-microscale architectures, diversification of materials properties, analysis of self-assembly pathways, and impartment of stimuli-responsive properties, are all becoming important issues in the research area of organic functional materials. This article focuses on the supramolecular assemblies of dyes and related pi-conjugated systems whose organization processes are rationally controlled by complementary multiple hydrogen bonding (CMHB) interactions between melamine and barbituric acid/cyanurate functional units. The article includes an overview of the construction principle of such systems, but special attention is focused on the work carried out in the authors's group (since 2002) using azobenzene, diarylethene, merocyanine, perylene bisimide dyes, and pi-conjugated oligomers including oligo(p-phenylenevinylene), oligo(p-phenyleneethynylene), and oligothiophenes. The design principles discussed in this account could open up new avenues to novel functional aspect and application of functional dyes and small-molecular pi-conjugated systems.