Effect of organic bicarboxylates on the structures of cobalt(II) coordination polymers derived from a semi-rigid bis(benzimidazole) derivative

Two new Co(II) coordination polymers, Co(L)(glu)] (1) and Co(L)(npht)]·H₂O (2) (H₂glu = glutaric acid, H₂npht = 3-nitrophthalic acid, L = 1,4-bis(5,6-dimethylbenzimidazol-1-ylmethyl)benzene), have been hydrothermally synthesized by self-assembly of cobalt chloride with a semi-rigid bis(benzimidazole) derivative and different organic bicarboxylic acids. Single crystal X-ray diffraction analysis reveals that complex 1 is a one-dimensional tube-like coordination polymer containing one helical Co-L] and two linear Co-glu] chains. In complex 2, two npht ligands connect two Co(II) atoms to form a binuclear Co(npht)]₂ subunit, which is further linked by L ligands with two kinds of conformations to form a 3-D CdSO₄-like framework. In addition, the electrochemical behaviors of the title complexes in bulk-modified carbon paste electrodes, and their thermal stabilities and fluorescent properties were investigated in this paper.