Influences of halogen atoms on indole-3-acetonitrile (IAN): Crystal structure and Hirshfeld surfaces analysis

• The substitute effect of halogen atoms on indole-3-acetonitrile (IAN) has been investigated.
• The π⋯π stacking motifs of the substituted IANs has been classified.
• The melting points of IANs have been correlated with N–H⋯N hydrogen bond interactions.

Crystal structural investigations and Hirshfeld surface analysis of three halogen atoms (4-Cl, 6-Cl and 4-Br) substituted indole-3-acetonitrile (IAN) were reported in this work. The structures of the present three compounds were characterized by Infrared spectra, Elemental analyses, NMR spectra, differential scanning calorimetry (DSC), thermogravimetric analyses (TGA) and hot stage microscopy (HSM). The Hirshfeld surfaces analysis in terms of crystal structure, intermolecular interactions and π⋯π stacking motifs were performed. We found that the different kinds of halogen atoms and the different substituted positions have a significant effect on the crystal structures, molecular π⋯π stacking motifs, melting points, and the nature of intermolecular interactions for IANs.