Synthesis, crystal structure and spectroscopic and Hirshfeld surface analysis of 4-hydroxy-3-methoxy-5-nitrobenzaldehyde

The title compound, C8H7NO5, is planar with an r.m.s. deviation for all nonhydrogen atoms of 0.018 angstrom. An intramolecular O-H center dot center dot center dot O hydrogen bond involving the adjacent hydroxy and nitro groups forms an S(6) ring motif. In the crystal, molecules are linked by O-H center dot center dot center dot O hydrogen bonds, forming chains propagating along the b-axis direction. The chains are linked by C-H center dot center dot center dot O hydrogen bonds, forming layers parallel to the bc plane. The layers are linked by a further C-H center dot center dot center dot O hydrogen bond, forming slabs, which are linked by C-O center dot center dot center dot pi interactions, forming a three-dimensional supramolecular structure. Hirshfeld surface analysis was used to investigate intermolecular interactions in the solid state. The molecule was also characterized spectroscopically and its thermal stability investigated by differential scanning calorimetry and by thermogravimetric analysis.