Crystal structures of 6-chloroindan-1-one and 6-bromoindan-1-one exhibit different intermolecular packing interactions

The two title compounds are analogs of 1-indanone that are substituted at the 6-position with chlorine and bromine. Although very similar in molecular structure, the crystal structures are not isomorphous and reveal that 6-chloroindan-1-one, C9H7ClO (I), and 6-bromoindan-1-one, C9H7BrO (II), exhibit unique intermolecular packing motifs. The molecules of the chloro analog (I) pack with a herringbone packing motif of C—H...O interactions, whereas the bromo derivative (II) packs with offset face-to-face π-stacking, C—H...O, C—H...Br and Br...O interactions. Compound (II) was refined as a two-component non-merohedral twin, BASF 0.0762 (5).