Structural Studies of a New Low Molecular Mass Organic Gelator for Organic Liquids Based on Simple Salt

A series of easy to prepare organic salt based on imidazole derivatives and cyclobutane-1,1-dicarboxylic acid have been studied for their gelation behavior after it was found that
imidazolium hydrogen cyclobutane-1,1-dicarboxylate (1) can harden few organic liquids. 1
forms remarkably stable gel (remains intact for several months in an open container, gel
dissociation temp TGel = 66 °C) with nitrobenzene at a very low concentration of 0.137 wt %,
whereas bis-imidazolium cyclobutane-1,1-dicarboxylate (2) resulted in a weak and unstable
gel with nitrobenzene, indicating the importance of the free COOH group in 1 in gel
formation. Molecular packing in the primary assembly unit (fibers) of xerogel of 1/nitrobenzene is successfully established based on single-crystal X-ray and X-ray powder diffraction
data. The morph responsible for gel formation of 1 with nitrobenzene is found to be different
from that of its xerogel. Substitution on the imidazole moiety results in nongelators.