Structural studies of a new low molecular mass organic gelator for organic liquids based on simple salt

Abstract

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 T_Gel = 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.