Cobalt(II) and Copper(II) Complexes Constructed from Bis(benzimidazole) and 2,6‐Pyridinedicarboxylate Co‐ligands: Synthesis, Crystal Structures, and Catalytic Properties

Three metal complexes based on the flexible bis(benzimidazole) derivatives, namely [Co 2 (L1) 4 (pydc) 2 ] · 2H 2 O ( 1 ), {[Cu(L1)(pydc)] · 0.75H 2 O} n ( 2 ), and [Co 2 (L2) 2 (pydc) 2 ] · 8H 2 O ( 3 ), [L1 = 1,2‐bis(5,6‐dimethylbenzimidazol‐1‐ylmethyl)benzene, H 2 pydc = 2,6‐pyridinedicarboxylic acid, L2 = 1,4‐bis(5‐methylbenzimidazol‐1‐ylmethyl)benzene] were hydrothermally synthesized and characterized by IR spectra, elemental analysis, UV/Vis diffuse refraction spectroscopy, and X‐ray single‐crystal diffraction. Complexes 1 and 3 exhibit a dinuclear structure composed of two central cobalt atoms bridged by flexible bis(benzimidazole) ligands and 3 finally packed into a two‐dimensional supramolecular network through π ··· π stacking interaction. Complex 2 shows a one‐dimensional zigzag chains motif, which further extended into a 2D supramolecular layer by face‐to‐face π···π stacking interactions. The luminescence properties of complexes 1 – 3 in the solid state at room temperature were described. Moreover, complexes 1 and 2 show higher catalytic activity than complex 3 for degradation of congo red azo dye in a Fenton‐like process.