5-Phenyl-3-(2-phosphono­eth­yl)-1,2,3-triazol-1-ium chloride

The new triazole-functionalized phospho­nic acid 5-phenyl-3-(2-phosphono­eth­yl)-1,2,3-triazol-1-ium chloride, C(10)H(13)N(3)O(3)P(+)·Cl(−) (PTEPHCl), was synthesized by the ‘click’ reaction of the alkyl azide diethyl-(2-azido­eth­yl)phospho­nate with phenyl­acetyl­ene to give the dieth­yl[2-(4-phenyl-1H-1,2,3-triazol-1-yl)eth­yl]phospho­nate ester, which was then hydrolyzed under acidic conditions (HCl) to give the ‘free’ phospho­nic acid. The use of HCl for the hydrolysis caused protonation of the triazole ring, rendering the compound cationic, charged-balanced by a Cl(−) anion. There are extensive hydrogen-bonding inter­actions in the structure of PTEPHCl, involving the phospho­nic acid (–PO(3)H(2)) group, the triazolium ring and the Cl(−) anion. [Image: see text]