The gelling behavior of some geminal diimidazoliumsalts was investigated in solvents differing in polarity and hydrogen bonddonor ability. The used salts, namely the 3,3′-di-n-decyl-1,1′(1,4-phenylenedimethylene)diimidazolium dibromide [p-Xyl-(decim)2][Br]2(1), the 3,3′-di-n-dodecyl-1,1′(1,4-phenylenedimethylene)diimidazoliumdibromide [p-Xyl-(dodecim)2][Br]2 (2), and the 3,3′-di-n-dodecyl-1,1′(1,4-phenylenedimethylene)diimidazolium ditetrafluoroborate [p-Xyl-(dodecim)2][BF4]2 (3), differ in the alkyl chain length and in theanion properties, such as size, shape, and coordination ability. In allcases in which gelation process was observed, the obtained gels werecharacterized by gel melting temperature determination, resonance lightscattering, and UV−vis measurements. On the whole, the investigationallowed to get information about both the thermodynamic stability andthe features of the aggregates characterizing the soft materials at theequilibrium. Data collected by us point out that the used organic salts are able to behave as both hydro- and organogelators. Inparticular, bromide salts formed hydrogels in the presence of α-cyclodextrin allowing to hypothesize that the gelation process isfavored by the formation of supramolecular assemblies. To verify this hypothesis, 1D and 2D 1H NMR measurements werecarried out. Both the alkyl chain length and the anion ability to reticulate the three-dimensional network proved to bedeterminant factors in affecting the gelation process as well as the features of the gel phases. Finally, with the future aim to usethe obtained gels as reaction media, the effect of a guest molecule such as the UV−vis active probe Nile Red was studied.
|Numero di pagine||11|
|Stato di pubblicazione||Published - 2012|
All Science Journal Classification (ASJC) codes