Imidazole-4-acetic Acid–Picric Acid (1/1) Complex

In the crystal structure of 4-(carboxymethyl)imidazol-3-ium picrate, C₅H₇N₂O₂⁺.C₆H₂N₃O₇⁻, the imidazole N3 atom is protonated and contacts the deprotonated phenol and nitro O atoms of picric acid through a bifurcated hydrogen bond. The carboxyl group of the imidazole-4-acetic acid is in a neutral state and participates in the dimer formation between centrosymmetrically related molecules through O...H-O hydrogen bonds. No significant stacking interaction is observed between the aromatic rings of both molecules, indicating the superiority of the hydrogen-bonding ability of imidazole-4-acetic acid over the π-donating ability of picric acid.

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