Novel 1,2,3-triazole-based compounds: Iodo effect on their gelation behavior and cation response

Two new series of 1,2,3-triazole derivatives, with and without iodo substitution, were synthesized and their gelation properties were measured. It was found that the iodo substitution at position 5 of triazole ring could greatly enhance the gelation ability. Scanning electron microscopy and X-ray diffraction reveal that the structures of the organogels from iodo and hydrogenous gelators are totally different. Iodo gels are selectively responsive to the stimuli of Hg 2+ , whereas hydrogenous gels can respond to Hg 2+ and Cu 2+ . Moreover, the reversible gel-sol transition of hydrogenous gels can be controlled by redox reaction or tuned with suitable chemicals. The single crystal analysis of reference compound ( C2 ) suggests that there are intermolecular and intramolecular non-classical hydrogen bonding interactions but no π-π interaction in hydrogenous gelator. The great difference between the two series of compounds results from the iodo effect and implies the existence of halogen bonding interaction in the iodo compounds.