Elucidating the Properties of a Novel [Ni(SCN)4] Complex

The newly synthesized crystalline compound, (C6H8N2)2Ni(SCN)4 .2(C6H9N2), features a trans-NiN¿ octahedral geometry where the Ni2+ center is coordinated by four thiocyanate ligands and two 2-amino-4-methylpyridine molecules. These discrete complexes assemble into linear chains along the crystallographic c-axis, stabilized into a 3D supramolecular framework by an intricate network of N-H ...N and N-H ...S hydrogen bonds. Characterized by XRD, FT-IR, and Hirshfeld surface analysis, the material functions as a semiconductor with a narrow 1.2 eV energy gap, a property resulting from intramolecular charge transfers and pi-orbital stacking that facilitates efficient charge carrier hopping. Although the framework remains thermally stable until degradation begins at 550 K, it exhibits a distinct phase transition at 435 K. Beyond its physical properties, molecular docking studies indicate that the compound possesses potential biological relevance, demonstrating a moderate binding affinity for the antioxidant-related protein peroxiredoxin 5.