Charge-transfer phenomena in novel, dual-component, sugar-based organogels.
The synthesis of a new saccharide-based gelator (2) containing a donor moiety has been described. Gelation experiments of a dual-component gel consisting of a saccharide-based gelator bearing an acceptor group (1) and of 2 have been performed in a variety of organic solvents and water. Moreover, gelation tests at different molar ratios of 1 and 2 have been performed in water, octanol, and diphenyl ether. In these last two solvents a gel color change was observed, from colorless to yellow, upon cooling of the sample to room temperature. This phenomenon was further investigated by UV-visible spectroscopy, which revealed the presence of charge-transfer interactions in the gel, in octanol. Temperature-dependence UV spectroscopy confirmed that such interactions occur in the gel but not in the corresponding solution sample. Furthermore, T(gel) measurements show that dual-component gels of 1 and 2 present increased thermal stability at a 50:50 ratio of the two gelators, in dependence of the solvent. Transmission electron microscopy (TEM) images of the single-component gels in diphenyl ether revealed that they consist of a fibrous network, while the dual-component gel presents a novel, helical, fibrous-bundle structure.
Friggeri
Arianna
A
Chemotransfiguration Project, Japan Science and Technology Corporation, Aikawa, Kurume, Fukuoka 839-0861, Japan.
Gronwald
Oliver
O
van Bommel
Kjeld J C
KJ
Shinkai
Seiji
S
Reinhoudt
David N
DN
D002236:Carbohydrate Conformation; D005782:Gels / Q000138:chemical synthesis / Q000737:chemistry*; D005960:Glucosides / Q000138:chemical synthesis / Q000737:chemistry*; D008854:Microscopy, Electron; D013056:Spectrophotometry, Ultraviolet
D005782:Gels; D005960:Glucosides