A novel copper(II) complex constructed with mixed ligands of biphenyl-4,4 '-dicarboxylic acid (H(2)bpdc) and dipyrido [3,2-d:2 ',3 '-f]quinoxaline (Dpq): Synthesis, structure, electrochemistry and electrocatalysis

A novel metal-organic framework [Cu-2(bpdc)(2)(Dpq)(2)(H2O)]center dot H2O (1) has been obtained from hydrothermal reaction of copper chloride with the mixed ligands [biphenyl-4,4'-dicarboxylic acid (H(2)bpdc) and dipyrido[3,2-d:2',3'-f]quinoxaline (Dpq)], and structurally characterized by elemental analysis, R TG and single-crystal X-ray diffraction analysis. The unique feature is that there simultaneously exist two kinds of one-dimensional (1-D) zigzag polymeric chains in complex 1. Moreover, the 1-D polymeric chains are ultimately packed into a three-dimensional (3-D) supramolecular framework through two different hydrogen bonding interactions. The adjacent different chains are linked by C-H center dot center dot center dot O hydrogen bonding interactions, and the same kind chains are further connected through C-H center dot center dot center dot pi stacking interactions. Additionally, the complex 1 was used as solid bulk-modifier to fabricate renewable carbon paste electrode (Cu-CPE) by the direct mixing method. The electrochemical behavior and electrocatalysis of Cu-CPE have been studied in detail. The results indicate that Cu-CPE give one-electron quasi-reversible redox waves in potential range of 400 to -300 mV due to the metal copper ion Cu(II)/Cu(I). The Cu-CPE showed good electrocatalytic activity toward the reduction of the bromate, nitrite and hydrogen peroxide. The electrocatalytic reduction peak currents of KBrO3, KNO2 and H2O2 showed a linear dependence on their concentrations. All of the results revealed that the Cu-CPE had a good reproducibility, remarkable long-term stability and especially good surface renewability by simple mechanical polishing in the event of surface fouling, which is important for practical application. (C) 2008 Elsevier Masson SAS. All rights reserved.