静岡大学 関朋宏 研究室

関朋宏 研究室

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Perylene Bisimide Organogels Formed by Melamine・Cyanurate/Barbiturate Hydrogen-Bonded Tapes

Ditopic melamines possessing one (1) or two (2) perylene bisimide (PBI) chromophores were synthesized and their self-aggregation and coaggregation with dodecyl cyanurate (dCA) or barbital (Bar) were investigated. Optically transparent organogels were formed through self-aggregation of 1 and coaggregation of 1 or 2 with dCA or Bar in nonpolar solvents. X-ray diffraction of the xerogels exhibited typical diffraction patterns assignable to lamellar structures, suggesting the formation of tapelike hydrogen-bonded motifs. Remarkably low critical gelation concentrations (cgc) of 8.0 × 10−4 M were revealed for all organogels, thus they can be classified as supergelators. Comparison of the thermal stabilities of the gels revealed that the gels containing 2 have higher melting temperatures (Tm) than those containing 1. Scanning electron microscopy and atomic force microscopy showed that the gels containing 1 are composed of sheetlike microstructures, whereas those containing 2 are composed of fibrous nanostructures, consistent with the difference in their thermal stabilities. The different self-assembled structures of our PBI aggregates can be related to whether extended stacks of PBI dyes along the hydrogen-bonded strands are possible or not.