Crystal structure of 7,8-dichloro-4-oxo-4H-chromene-3-carbaldehyde

Abstract

In the title compound, C10H4Cl2O3, a dichlorinated 3-formylchromone derivative, the fused-ring system is slightly puckered [dihedral angle between the benzene and pyran rings = 3.66 (10)°]. The dihedral angle between the pyran ring and the formyl plane is 8.64 (7)°. In the crystal, molecules are linked through π–π stacking interactions [centroid–centroid distance between the benzene and pyran rings = 3.727 (2) Å], C—H...O hydrogen bonds and short C...O contacts [2.838 (4) Å]. Halogen bonds between the formyl O atoms and the Cl atoms at the 7-position [Cl...O = 2.984 (3) Å, C—Cl...O = 170.83 (12)° and Cl...O—C = 116.05 (19)°] are also formed along the a axis, resulting in helical structures constructed by C—H...O hydrogen bonds and Cl...O halogen bonds along the b axis. In addition, type II halogen–halogen contacts between the chlorine atoms at the 7- and 8-positions [Cl...Cl = 3.519 (2) Å, C–Cl...Cl = 171.24 (10)° and 88.74 (11)°] are observed.

Keywords

• crystal structure
• π–π stacking
• hydrogen bond
• halogen bond
• halogen–halogen interaction