PH-Controlled assembly of two POM-based inorganic–organic hybrid copper coordination polymers: synthesis, structures and properties

Abstract

Two POM-based copper coordination polymers constituted by Keggin-type polyoxometalates (POMs), [Cu2 (SiW12O40)2 (Fbtx)3 (H2O)4]n (1) and {[Cu2 (SiW12O40) (Fbtx)2 (H2O)2.75]·4.5H2O}n (2) (Fbtx = 2,3,5,6-tetrafluoro-1,4-bis (1,2,4-triazole-1-ylmethyl)benenze) have been hydrothermally synthesized by the same precursor at different pH values and structurally characterized by single-crystal X-ray diffraction, powder X-ray diffraction, element analyses and IR. Both of them have two-dimensional coordination layers constructed by bidentate SiW12O404− anions and bridging Fbtx ligands, in which complex 1 exhibits a 2D + 2D → 2D interpenetrated network with sql topology, while complex 2 features a binodal 3,5-connected network bearing new topology with a Schlafli symbol of {44;66}{62;10}. Additionally, the thermal stability, fluorescent properties and photocatalytic properties of complexes 1 and 2 have also been investigated. The results indicate that complexes 1 and 2 can serve as recyclable heterogeneous photocatalysts and show good catalytic activity for the degradation of Rhodamine B under UV irradiation.