▎ 摘　　要

Two novel coordination compounds, [Cu(L)Cl-2] and [Co(L)Cl-2] (L = 4-(6-hydroxy-phenyl)-2,6-di(thiazol-2-yl) pyridine), are successfully synthesized. The structure of the compounds was verified by instrumental techniques, including ultraviolet-visible spectroscopy, Fourier transform infrared spectroscopy, proton nuclear magnetic resonance spectroscopy, and mass spectrometry. The graphene oxide, previously modified by spontaneous coupling of diazonium salt of 4-amino benzoic acid, was covalently bound with [Cu(L)Cl-2] and [Co(L)Cl-2] compounds. The covalent attachment of the metallic complexes to the graphene oxide was confirmed by Fourier transform infrared spectroscopy and cyclic voltammetry. Functionalized surfaces through metallic coordination compounds showed catalytic reactivity to individual electrochemical oxidation of ascorbic acid, dopamine, and uric acid as revealed by the enhancement in the anodic peak current and the shifted oxidation peak potentials of each three analytes in comparison to the plain glassy carbon and graphene oxide. The resulting electrodes were shown to be utilized for the simultaneous detection of ascorbic acid, dopamine, and uric acid due to the appearance of the well-separated and resolved three different anodic peaks. The sensitivity of both modified electrodes for each biological compound was tested within the linear range of 2 to 15 mu M for ascorbic acid, 0.2 to 3 mu M for dopamine and uric acid, and the limit of detection values for ascorbic acid, dopamine, and uric acid are found to be 1.84 mu M, 0.41 mu M, and 0.32 mu M, respectively for [Cu(L)Cl-2] and 1.94 mu M, 0.33 mu M, and 0.52 mu M for [Co(L)Cl-2]. Furthermore, constructed electrochemical sensor platforms exhibited decent stability, selectivity, and reproducibility for the simultaneous detection of target biomolecules. Graphic Abstract