Hydrothermal synthesis, crystal structure, and electrochemical property of a new 3-D coordination polymer based on benzene-1,2,4,5-tetracarboxylate bridging ligand: [Cu2(btec)(en)2]n

A new 3-D copper(II) complex, formulated as [Cu2(btec)(en)2]n (1) [H4btec = benzene-1,2,4,5-tetracarboxylate, and en = ethylenediamine], was hydrothermally synthesized and structurally characterized by elemental analysis, IR spectroscopy, thermal gravimetric analysis, and single crystal X-ray diffraction. The structural analysis of 1 reveals that copper(II) connect by 6-bridging btec to form a 3-D coordination polymer, in which four carboxylates of btec show monodentate and bidentate coordination. Complex 1 was used as solid bulkmodifier to fabricate renewable carbon paste electrode (1-CPE) by direct mixing method. The cyclic voltammogram of 1-CPE displayed one-electron quasi-reversible redox waves in potential range 300 to -300 mV due to Cu(II)/Cu(I). Moreover, 1-CPE showed electrocatalytic activity toward the reduction of nitrite.