Perylene bisimide organogels formed by melamine·cyanurate/barbiturate hydrogen-bonded tapes

Abstract

Ditopic melamines possessing one (1) or two (2) perylene bisimide (PBI) chromophores were synthesized and their selfaggregation 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 Â 10 À4 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 (T m ) 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.

Functional π-Gelators and Their Applications

“…The melamine derivative functionalized with only one PBI unit 171e (Chart ) was reported to form organogel upon self-aggregation, also in the presence of dCA. 429 However, hydrogen bonded complex of 171d-dCA and 171e-BU failed to gelate any of the solvents tested. The aggregation of 172a (dimer) and 172b (hexamer) resulted in folded conformation with the two PBI units through an intramolecular process and formed large molecular aggregates via an intermolecular process (Figure 29).…”

“…FET measurements of the lamellar structures exhibited an electron mobility value of 1 × 10 –4 cm 2 V –1 s –1 . The melamine derivative functionalized with only one PBI unit 171e (Chart ) was reported to form organogel upon self-aggregation, also in the presence of dCA . However, hydrogen bonded complex of 171d - dCA and 171e - BU failed to gelate any of the solvents tested.…”

Solvent-induced self-assembly of hydrogen bonded P4VP-perylenebisimide comb polymer

“…Numerous research reports are available in literature demonstrating the self assembly of perylenebisimide derivatives in solution giving rise to nanoscale morphologies including rods, bers, ribbons, tubes etc. [16][17][18][19][20] The majority of these are either perylenediimide small molecules or low molecular weight oligomers. Polymers as well as small molecules have their own advantages and disadvantages when considered for semiconductor applications.…”

Organogels Fabricated from Self-Assembled Nanotubes Containing Core Substituted Perylene Diimide Derivative

“… 35 , 36 The peak at 21.6° ( d = 4.1 Å) belongs to the liquid-like packing order of long alkyl chains located at the core positions of PDI-1 . 44 , 45 The third-order diffraction peak of 21.6° appears at 7.4° ( d = 11.87 Å) belonging to the (010) plane. The d -value ratio 1:√3 of peaks at 21.6° ( d = 4.1 Å) and 12.4° ( d = 7.13 Å) indicates hexagonal packing of PDI-1 molecules in toluene organogel.…”