The coordination chemistry and supramolecular interactions of 2-(2′-Pyridyl)imidazole ligand: a comprehensive review with theoretical insight

Abstract This review explores the role of 2-(2′-Pyridyl)imidazole (PyimH) as a coordinating ligand and also its role as a supramolecular agent through hydrogen bonding and π ⋯ π interaction. Two N coordination sites make 2-(2′-Pyridyl)imidazole an analogous ligand to 2,2′-bipyridine. The syn orientation of imidazole and pyridine sp 2 nitrogen makes it a bidentate chelating ligand. PyimH mainly produces discrete coordination complexes (0D), but in a few cases, 1D coordination polymers are observed due to bridging co-ligands like oxalate, dicyanamide, tricyanomethanide, croconate, thiocyanate, and iso-thiocyanate. These discrete coordination units and co-ligand bridged 1D coordination polymers are further augmented to higher dimensional supramolecular systems having linear, zig-zag, ladder-shaped, ribbon-like, and helical geometry. These supramolecular structures are stabilized by intermolecular hydrogen bonding interaction (N–H⋯N, N–H⋯O, O–H⋯N, O–H⋯O, and C–H⋯O) and π ⋯ π interaction capability of PyimH ligand. PyimH generally acts as an excellent chelating ligand for a range of metal ions and is also a capable supramolecular glueing agent due to hydrogen bonding and π -stacking ability.