1 research outputs found
Self-Assembly of Ketals of Arjunolic Acid into Vesicles and Fibers Yielding Gel-Like Dispersions
Ten aliphatic and aromatic ketals of arjunolic acid,
a renewable,
nanosized triterpenic acid which is obtainable from <i>Terminalia
arjuna</i>, have been synthesized upon condensation with aldehydes.
Self-assembly properties of the ketals have been studied in a wide
range of organic liquids. With the exception of the <i>p</i>-nitrobenzylidene derivative, low concentrations of the ketals self-assemble
and form gel-like dispersions in many of the organic liquids examined.
The morphologies of the assemblies, studied at different distance
scales by optical, electron, and atomic-force microscopies, consisted
of fibrillar networks and vesicles which were able to entrap 5(6)-carboxyfluorescein
as a guest molecule. X-ray diffractograms indicate that the fibrillar
objects are crystalline. A charge-transfer complex was formed from
a 1:1 mixture of ketal derivatives with electron-donating and electron-accepting
groups, and the 9-anthrylidene derivative in its fibrillar network
dimerized upon irradiation. Results demonstrate that subtle changes
in the ketal structures can lead to very different aggregation pathways