Click synthesis and characterization of 1,2,3-triazolium salts

Abstract

New triazolium compounds: 4-(2-formylphenyl)-3-methyl-1-propyl-1H-1,2,3-triazol-3-ium iodide, 3, 4,4’-(((1E)-(butane-1,4-diylbis(azanylylidene))bis(methanylylidene))bis(2,1-phenylene))bis(3-methyl-1-propyl-1H-1,2,3-triazol-3-ium) iodide,4, and, 4-(2-formylphenyl)-3-methyl-1-propyl-1H-1,2,3-triazol-3-ium hexafluorophosphate,5, were synthesized and fully characterized by 1H &13C NMR, EA, IR spectroscopy, MS and single crystal X-ray diffraction analysis for 4 and 5. Compound 3 was obtained by adaptation of the ‘click’ Cu(I) catalyzed [3 + 2] cycloaddition reaction to yield the 1,2,3 triazole that was alkylated with methyl iodide. Schiff base condensation of 3 with a diamine led to the isolation of compound 4 in excellent yield and anion metathesis of 3 with KPF6 yielded 5. The single crystal X-ray diffraction results reveal that both compounds 4 and 5 crystallized in the P-1 space group of the triclinic system. The dihedral angles between the planes of the triazole rings in 4 and 5 and the planes of the respective phenyl rings were found to be 72.8(6)° and 62.8(3)° which is indicative of strong deviation from coplanarity. The solid-state structures of 4 and 5 are further stabilized by weak intramolecular C–H … π and intermolecular C–H … X (X = F, I) non-bonded interactions. Results of Hirshfeld surface contacts analysis and associated two-dimensional fingerprint plots also correlate with the observed intermolecular interactions in the crystals of 4 and 5.