One-dimensional coordination polymers constructed from bicapped Keggin polyoxometalate and cyclic tetranuclear CuI cluster bridged by asymmetrical bipyridine derivative

This article reports two new bicapped Keggin-based hybrid compounds, {[Cu4I(cppy)4][PMo7VIMo5VO40(VIVO)2]}·2H2O (1) and {[Cu4I(cppy)4][SiMo8VIMo4VO40(VIVO)2]}·2H2O (2) (cppy = 4-(5-(4-chlorophenyl)pyridin-2-yl)pyridine), synthesized under hydrothermal conditions and characterized by X-ray single-crystal diffraction, elemental analyses, IR, XPS, TG and CV analyses. Structural characterization shows that the two compounds are isostructural, consisting of square tetranuclear [Cu4I(cppy)4]4+ circuits and reduced bivanadyl Keggin clusters. The tetranuclear [Cu4I(cppy)4]4+ circuit is ‘windstick’-style. The polyoxoanions acting as junctures connect the tetranuclear circuits to construct a chain. These chains are further connected through π⋯π interactions, halogen bonding and hydrogen bonding interactions to construct a 3D superamolecular structure. The electrochemical behaviors of the 1-CPE have been studied in detail.

Graphical abstractThe Cu(I) ions and the cppy molecules construct the square tetranuclear [Cu4I(cppy)4]4+ circuit, with ‘windstick’-style. The circuits are connected by the bicapped polyoxoanions to construct a 1D chain. The two neighboring chains arrange across like a ‘zipper’.Figure optionsDownload full-size imageDownload as PowerPoint slide