Abstract:

A new 3D Supramolecular compound, [Co2(Dpq)2(btec)(H2O)6]•2H2O (1), has been obtained from hydrothermal reaction of cobalt(II) nitrate with mixed ligands [1,2,4,5-benzenetetracarboxylate (btec) and dipyrido[3,2-d:2′,3′-f]quinoxaline (Dpq)], and structurally characterized by element analysis, IR, TG and single-crystal X-ray diffraction. The result reveals that the compound belongs to monoclinic system with P2(1)/c space group. The cell parameters are: a= 0.8978(5) nm, b= 2.9822(16) nm, c= 0.7058(4) nm, β= 94.199(6) º, V= 1.8848(18) nm3, Z= 2, R1= 0.0350, wR2= 0.0796. The Co(II) is coordinated with two nitrogen atoms of one Dpq molecule, one oxygen atom from bridging ligand btec, and three oxygen atoms belong to coordinated water molecules, respectively, rendering a six-coordinate mode in a distorted octahedron geometry. Each two Co(II) ions are linked by the bridging ligand btec to construct a dinuclear unit . The 3D supramolecular network of title compound is formed through hydrogen bonds and π-π stacking interactions. Moreover, the electrochemical properties of 1 bulk modified carbon paste electrode (1-CPE) have been studied, and the results indicate that the 1-CPE give one-electron redox wave in potential range of 600 to −300 mV due to the metal cobalt ion Co(II)/Co(III). The 1-CPE has good electrocatalytic activity toward the oxidation of nitrite in 0.1 M HAc-NaAc suffer solution.

Key words: hydrothermal synthesis, cobalt compound, crystal structure, supramolecular network, electrochemical property