Synthesis, characterization and photoluminescence properties of an organic–inorganic hybrid monolacunary Keggin-type polyoxotungstate

Abstract

An organic–inorganic hybrid lanthanide-based polyoxometalate (Ln-POM) [N(CH3)4]3K2[Tb(C7H5O3)(H2O)2(α-PW11O39)]·10H2O (1) was synthesized and further characterized by single crystal X-ray diffraction analysis, elemental analyses, Inductive Coupled Plasma Emission Spectrometer (ICP), powder X-ray diffraction (PXRD), Fourier transform infrared (FTIR) spectroscopy, solid-state UV/vis spectrum and thermogravimetric analyses (TGA). Single-crystal X-ray diffraction analyses indicated that both organic ligand and [α-PW11O39]7− group directly bind Tb3+ center for the formation of polyanion in 1. The photoluminescence property of 1 was investigated at room temperature, and the results showed that compound 1 exhibits lower energy transfer efficiency from POM fragment and organic ligand to Tb3+ ion. Furthermore, time-resolved emission spectroscopy indicates that the photoexcitation O → M ligand to metal charge transfer (LMCT) of POM fragments and organic ligand can sensitize the Tb3+ ions through intramolecular energy transitions in 1.