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

Abstract

The new triazole-functionalized phosphonic acid 5-phenyl-3-(2-phosphonoethyl)-1,2,3-triazol-1-ium chloride, C10H13N3O3P+·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 (–PO3H2) group, the triazolium ring and the Cl− anion.