An organic chromophore modified samarium-containing polyoxometalates: excitation-dependent color tunable behavior from organics to lanthanide ion
Here, an organic-inorganic hybrid lanthanide-based polyoxometalate (Ln-POM) [N(CH3)4]3K2Sm(C7H5O2)(H2O)2(α-PW11O39)]·11H2O (1) was successfully synthesized and characterized well by several physicochemical techniques. In the polyanion of 1, the benzoic acid ligand directly binds Sm3+ ion for the formation of an organic-inorganic hybrid polyanion. This organic-inorganic hybrid structure can effectively sensitize the emissions of Sm3+ ion, which have been confirmed by photoluminescence and time-resolved emission spectroscopy of 1. The photoluminescence study demonstrates that Sm3+ ion possesses a relatively high-symmetric coordination geometry, which is well consistent with the structural analysis of Sm3+ ion in 1. Furthermore, the polyanion of 1 can form a 3D 4,8-topology framework through the linkage of K1 and K2 ions. In addition, the color-tunable photoluminescence properties of 1 have been explored, revealing 1 shows a reversible color-tunable photoluminescence property based on excitation from 260 nm to 350 nm, emitting color from blue to pink.