A new halogen bonding 1,2-iodo-triazolium-triazole benzene motif for anion recognition

Abstract

The synthesis of a series of halogen bonding (XB) acyclic anion receptors based on a novel 1,2-iodo-triazolium-triazole benzene motif is reported. A combination of one- and two-dimensional 1H and 19F NMR spectroscopic techniques elucidate key conformational effects associated with the incorporation of ortho-substituted iodo-triazole based XB donors. 1H NMR anion titration experiments highlight the anion recognition potency of a mono-cationic XB iodo-triazolium-triazole benzene receptor, remarkably forming stronger halide complexes in comparison to a dicationic hydrogen bonding (HB) bis-proto-triazolium receptor analogue. X-ray crystal structure analysis provide insights into halide binding induced conformational changes and coordination modes, revealing the unique electronic and steric consequences associated with multidentate XB donor arrays.