Crystal structure and Hirshfeld surface analysis of [FeCl ₄ ( <i>L</i> H) ₂ ] ( <i>L</i> H = 1 <i>H</i> -imidazo[4,5- <i>b</i> ]pyridin-4-ium)

The title coordination complex tetra-chlorido-bis-(1<i>H</i>-imidazo[4,5-<i>b</i>]pyridin-4-ium-κ<i>N</i> ³)iron(II), [FeCl₄(C₆H₆N₃)₂] or [FeCl₄(LH)₂], was synthesized and structurally characterized by single-crystal X-ray diffraction. The complex crystallizes in the triclinic space group <i>P</i>1. The iron atom (site symmetry ) is hexa-coordinated, adopting a slightly distorted octa-hedral geometry defined by two 1<i>H</i>-imidazo[4,5-<i>b</i>]pyridinium ligands and four chloride anions. In the crystal, N-H⋯Cl hydrogen bonds generate two-dimensional layers parallel to the <i>ab</i> plane, while the three-dimensional supra-molecular framework is further consolidated by C-H⋯Cl inter-actions. In addition, π-π stacking inter-actions contribute to the overall cohesion of the crystal structure. Hirshfeld surface analysis indicates the significance of various inter-molecular contacts in the crystal packing, with major contributions from Cl⋯H/H⋯Cl (43.2%), H⋯H (22.5%), C⋯H/H⋯C (16.4%), H⋯N/N⋯H (4.4%), N⋯C/C⋯N (3.7%), C⋯C (3.6%), Cl⋯N/N⋯Cl (3.2%), Cl⋯C/C⋯Cl (2.4%), and N⋯N (0.6%) inter-actions.