Synthesis, characterization and electrochemical properties of two metal cobalt complexes constructed by tetradentate carboxylic

Abstract

Two new three-dimensional coordination polymers (CPs), [Co(H2L2−) (bibp)]·2H2O (1) and [Co2(L4−) (bib)2]·8H2O (2) (bib = 1,4-diimidazolyl butane, bibp = 4,4′-diimidazolylbiphenyl) have been solvo-/hydrothermal prepared based on tetradentate ligand 5,5-(pentane-1,4-diylbis (oxy))diisophthalic acid (H4L). In CP 1, two chains was formed by Co(II) ion with ligands H2L2− and bibp, respectively, then two chains form into a 2D layer through Co(II) ion. The same two 2D layers constitute a AB layer by inverted manner, then a 3D framework was obtained through the combination of AB layer by π-π stacking. In CP 2, Co (II) atoms are connected by neighboring carboxylic acid ligands L4− to generate 2D layer, then being further connected with nitrogen-containing ligand bib, the 2D layer form a 3D supramolecular network through Co(II) ions. In addition, the electrochemical behaviors of complexes 1 and 2 have been reported.