Hydrogen-Bonding Patterns in Substituted Oxines. Redetermination of 8-Hydroxy-7-iodoquinoline-5-sulfonic Acid

For the title compound, C₉H₆INO₄S, only a structure derived from photographic data is available in the literature with R = 0.14 [Merritt & Duffin (1970). Acta Cryst. B26, 734-744]. The structure has now been redetermined using diffractometer data. H atoms were located from Fourier maps. The sulfonic group is deprotonated, the proton having migrated to the quinoline N atom which forms intramolecular and intermolecular hydrogen bonds. The protonation of N1 causes an enhancement of the internal angle at N1 and an asymmetry in the external angles at C8. The H atom of the hydroxyl group is distal to the ring N atom.

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