Construction of anderson-type polyoxometalate-based complexes involving in situ ligand transformation with capacitive and electrochemical sensing performances

For developing polyoxometalate-based hybrids as potential energy storage and electrochemical materials, 3, 5-di(1H-imidazol-1-yl)benzonitrile (DICN) and 5- (1H-imidazol-1-yl)isophthalonitrile (IMIPN) as precursors were employed, and three Anderson-type polyoxometalate-based complexes, [{Cu-3(H2O)(8)(HDIBA)(2)} {TeMo6O24}]& sdot;6H(2)O (1), [{Cu-4(H2O)(10)(HIMIPA)(2)}{TeMo6O24}]& sdot;2H(2)O (2) and Ni(H2O)(6)[{Ni-2(H2O)4(H(2)IMIPA)(2)} {TeMo6O24}]& sdot;4H(2)O (3), were prepared under hydrothermal condition. The initial DICN and IMIPN were transformed in situ into 3,5-di(1H-imidazol-1-yl)benzoic acid (HDIBA) and 5-(1H-imidazol-1-yl)isophthalic acid (H(2)IMIPA). In 1, the polyoxometalate-based inorganic chains containing single-bridged copper linkages were extended by the imidazole groups of HDIBA ligand, but the chains in 2 and 3 embodied the double-bridged copper and nickel linkages, further linked by the imidazole and carboxyl groups from HIMIPA ligand. Complexes 1-3 demonstrated outstanding capacitive performances (i.e., specific capacitances of 944F & sdot;g(- 1) for 1, 1548.6F & sdot;g(-1) for 2 and 718.6F & sdot;g(-1) for 3 at 1 A & sdot;g(-1)), as well as electrochemical sensing activities for bromate. The results provided a feasible way for the design and synthesis of Anderson-type POM-based complexes used as high-performing electrode materials in energy store and sensor-related applications.