C-I...N and C-I...π halogen bonding in the structures of 1-benzyliodoimidazole derivatives

Halogen bonding is a well-established and intensively studied intermolecular interaction that has also been used in the preparation of functional materials. While polyfluoroiodo- and polyfluorobromobenzenes have been widely used as aromatic halogen-bond donors, there have been very few studies of iodoimidazoles with regard to halogen bonding. We describe here the X-ray structures of three iodoimidazole derivatives, namely 1-benzyl-2-iodo-1H-imidazole, C₁₀H₉IN₂, (1), 1-benzyl-4-iodo-1H-imidazole, C₁₀H₉IN₂, (2), and 1-benzyl-2-iodo-1H-benzimidazole, C₁₄H₁₁IN₂, (3), and the halogen bonds that dominate the intermolecular interactions in each of these three structures. The three-dimensional structure of (1) is dominated by a strong C-I...N halogen bond, with an N...I distance of 2.8765 (2) Å, that connects the molecules into one-dimensional zigzag ribbons of molecules. In contrast, the three-dimensional structures of (2) and (3) both feature C-I...π halogen-bonded dimers.