Despite the large number of reported crystalline structures of coordination complexes bearing pyridines as ligands, the relevance of π-π interactions among these hereroaromatic systems in the stabilization of their supramolecular structures and properties is not very well documented in the recent literature. The title compound, [CoCl2(C5H6N2)2], was obtained as bright-blue crystals suitable for single-crystal X-ray diffraction analysis from the reaction of 4-aminopyridine with cobalt(II) chloride in ethanol. The new complex was fully characterized by a variety of spectroscopic techniques and single-crystal X-ray diffraction. The crystal structure showed a tetrahedral complex stabilized mainly by bidimensional motifs constructed by π-π interactions with large horizontal displacements between the 4-aminopyridine units, and N-H...Cl hydrogen bonds. Other short contacts, such as C-H...Cl interactions, complete the three-dimensional arrangement. The supramolecular investigation was extended by statistical studies using the Cambridge Structural Database and a Hirshfeld surface analysis.
Keywords: 4-aminopyridine; Hirshfeld analysis; cobalt complex; crystal structure; fingerprint plots; pyridine–pyridine dimer; π–π stacking.