Two new helical compounds based on Keggin clusters and N-donor multidentate ligand: Syntheses, structures and properties

•The tridentate L ligand is first used to synthesis Keggin-type polyoxometalates.•The two compounds possess the left- and right-handed Cu–L helical chains.•Relationship between surface properties and photocatalytic activity was studied.•Two compounds exhibit photoluminescence of ligand-to-metal charge transfer.

Two isostructural polyoxometalate-based inorganic–organic hybrids with 1D helical chain, [CuH3L2(GeMo12O40)]·2H2O (1) and [CuH3L2(SiMo12O40)]·2H2O (2), where L=2,4,5-tri(4-pyridyl)-imidazole have been synthesized under hydrothermal conditions. It is the first time to use the L ligand to synthesis the Keggin-type polyoxometalate-based inorganic–organic hybrids. The two compounds possess the left- and right-handed helical chains and the POMs as pendants attach in the helical chains through Cu–O bonds. The two compounds have been characterized by elemental analyses, infrared (IR) spectroscopy, powder X-ray diffraction (PXRD), X-ray photoelectron spectra (XPS), thermogravimetric analysis (TGA) and photoluminescent spectroscopy. Moreover, nitrogen adsorption−desorption measurement, electrochemical and photocatalysis properties for degradation of methylene blue (MB) upon a UV irradiation of compound 1 have been examined.

Graphical abstractTwo new compounds, [CuH3L2(GeMo12O40)]·2H2O (1) and [CuH3L2(SiMo12O40)]·2H2O (2) have been synthesized under hydrothermal conditions. The two compounds possess the left- and right-handed helical chains.Figure optionsDownload full-size imageDownload as PowerPoint slide