2-Hydroxy-3-methoxybenzaldehyde (o-vanillin) revisited

Abstract

The structure ofortho-vanillin, C8H8O3, has been revisited with modern methods and at low temperature (100 K). The previous structure [Iwasakiet al.(1976).Acta Cryst. B32, 1264–1266] is confirmed, but geometric precision is improved by an order of magnitude. The C atom of the methoxy group lies close to the benzene ring plane, which is the most common geometry for –OMe groups lyingorthoto –OH groups on an aromatic ring. The crystal structure displays one intramolecular O—H...O and three weak intermolecular C—H...O hydrogen bonds.