A new
![greek small letter alpha greek small letter alpha](http://www.sciencedirect.com/scidirimg/entities/204e.gif)
-Keggin POM derivative
![View the MathML source View the MathML source](http://www.sciencedirect.com/cache/MiamiImageURL/B6TG5-4PKPGYG-1-23/0?wchp=dGLzVlz-zSkzS)
(
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
![View the MathML source View the MathML source](http://www.sciencedirect.com/cache/MiamiImageURL/B6TG5-4PKPGYG-1-24/0?wchp=dGLzVlz-zSkzS)
is decorated by a single capping {Cu(DF)}
2+ subunit
via four bridging oxygen atoms on a {Mo
4O
4} pit. The isolated copper dimer unit
![View the MathML source View the MathML source](http://www.sciencedirect.com/cache/MiamiImageURL/B6TG5-4PKPGYG-1-25/0?wchp=dGLzVlz-zSkzS)
acts as counter cation, in which the organic ligand DF exhibits a rare coordination mode. Furthermore, the capped Keggin polyoxoanions
![View the MathML source View the MathML source](http://www.sciencedirect.com/cache/MiamiImageURL/B6TG5-4PKPGYG-1-14/0?wchp=dGLzVlz-zSkzS)
are fused together
via the copper dimers through the weak Cu
![cdots, three dots, centered cdots, three dots, centered](http://www.sciencedirect.com/scidirimg/entities/22ef.gif)
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.