A new CuII(4,5-diazafluoren-9-one)-capped Keggin derivative: Hydrothermal synthesis and crystal characterization

A new α-Keggin POM derivative [Cu2I(DF)2H2O][HPMo10VIMo2VO40{CuII(DF)}] (1) (DF = 4,5-diazafluoren-9-one) has been prepared under hydrothermal conditions and characterized by single-crystal X-ray diffraction, elemental analysis, IR, XPS spectra, thermogravimetric analysis and cyclic voltammetry. In compound 1, the polyoxoanion cluster [PMo10VIMo2VO40]5- is decorated by a single capping {Cu(DF)}2+ subunit via four bridging oxygen atoms on a {Mo4O4} pit. The isolated copper dimer unit {Cu2I(DF)2H2O}2+acts as counter cation, in which the organic ligand DF exhibits a rare coordination mode. Furthermore, the capped Keggin polyoxoanions [PMo10VIMo2VO40{CuII(DF)}]3- are fused together via the copper dimers through the weak Cu ⋯ O interactions to form chains. Hybrid 1 was used as a solid bulk modifier to fabricate a carbon paste electrode (1-CPE) by direct mixing. The electrochemical and electrocatalytic behaviors of the 1-CPE have been studied in detail.

Graphical abstractCompound [Cu(IDF)2H2O][HPMo10VIMo2VO40{CuII(DF)}] (1) consists of a copper capped polyoxoanion [PMo10VIMo2VO40{CuII(DF)}]3− and one discrete copper dimer unit {Cu2I(DF)2H2O}2+, in which the organic ligand DF exhibits a rare coordination mode. The electrochemical and electrocatalytic behaviors of the 1-CPE have been studied in detail.Figure optionsDownload full-size imageDownload as PowerPoint slide