The betainic form of (imidazol-2-yl)phenylphosphinic acid hydrate

Abstract

Single crystals of the title compound, (imidazolium-2-yl)phenylphosphinate monohydrate, C9H9N2O2·H2O, were obtained from methanol/water after deprotection and oxidation of bis(1-diethoxymethylimidazol-2-yl)phenylphosphane. In the structure, several N–H...O and P—O...H–O hydrogen bonds are found. π–π interactions between the protonated imidazolyl rings [centroid–centroid distance = 3.977 (2) Å] help to establish the crystal packing. The hydrate water molecule builds hydrogen bridges to three molecules of the phosphinic acid by the O and both H atoms.