ABSTRACT
The facile tuning of the fluorescent properties of organogels is highly desirable for optical switches, light-emitting diodes, chemosensors and bioprobes. The design of organic molecules with multiple emission colors but only one molecular platform remains challenging. Herein, a new cholesterol-based organogelator N1 containing D-A pairs (salicylaldehyde and naphthalimide units) was designed. We successfully obtained multiple solvent-tuned emission colors in both the solution and gel states using a unimolecular platform. Moreover, the effects of the solvent on the gel morphology, rheology and anion-responsive properties were studied. Finally, we showed that the gel in benzene displayed reversible thermochromic properties with changes in emission color from yellow-green to red. Several experiments suggested that a short-distance and ordered array of the D-A pairs facilitated the efficient intermolecular electron transfer of the fluorophores.
ABSTRACT
A sugar functionalized naphthalimide derivative (H1) self-assembles into supramolecular nanotubes (25 nm pore diameter) by the reaction of 4-N-ethylaminenaphthalimide-N-propinyl and delta-gluconolactone in refluxed ethanol. The suspension of the tube assembly in water can directly form hydrogels when triggered by sonication, without change in morphology or molecular aggregates in the pH range of 5-8. Modified with aminocarproic acid, H2 with more hydrogen bonding sites can form pH tolerant hydrogels in the widest range of pH values from 1-14 accelerated by sonication. The gelation mechanism was studied in detail. To the best of our knowledge, this is the first paradigm wherein hydrogels were constructed from naphthalimide derivatives. Finally, the potential of the hydrogel as a drug delivery and release system for hydrophilic medicine was explored.
