title: Syntheses, structures and fluorescence properties of three rare-earth containing docosatungstates.
abstract: Three rare-earth containing docosatungstates Na3H2[RE(H2O)4][RE(H2O)5]2[W22O74H2]·36H2O [RE=DyIII(1), HoIII(2), YIII(3)] have been synthesized by reaction of Na2WO4·2H2O, dimethylamine hydrochloride (DMAHC) and RE(NO3)3·6H2O in the aqueous solution and characterized by elemental analyses, IR spectra, thermogravimetric (TG) analysis, powder X-ray diffraction (PXRD) and single-crystal X-ray diffraction. 1-3 are isomorphous and each molecular unit consists of a S-shaped docosatungstate [W22O74H2]14-polyoxoanion with two supporting [RE(H2O)5]3+cations and one disordered [RE(H2O)4]3+cation. The [W22O74H2]14-polyoxoanion can be viewed as combination of two hendecatungstate [W11O38H]9-subunits in the staggered fashion by sharing two μ2-O atoms. The TG curves of 1-3 reveal the one-step weight loss between 25°C to 700°C. Moreover, both 1 and 2 demonstrate the characteristic luminescence emission behaviors of the corresponding RE3+ions and their lifetime decay curves can be well fitted to the double exponential function. In addition, the CIE chromaticity coordinates of 1 and 2 have been obtained based on their corresponding emission spectra, and their dominant wavelengths and color purities have been also calculated.
authors.affiliation: Henan Key Laboratory of Polyoxometalate Chemistry, Institute of Molecular and Crystal Engineering, College of Chemistry and Chemical Engineering, Henan University, Kaifeng, Henan 475004, PR China.
authors.forename: Hailou
authors.initials: H
authors.lastname: Li
authors.affiliation: Henan Key Laboratory of Polyoxometalate Chemistry, Institute of Molecular and Crystal Engineering, College of Chemistry and Chemical Engineering, Henan University, Kaifeng, Henan 475004, PR China.
authors.forename: Yajie
authors.initials: Y
authors.lastname: Liu
authors.affiliation: Henan Key Laboratory of Polyoxometalate Chemistry, Institute of Molecular and Crystal Engineering, College of Chemistry and Chemical Engineering, Henan University, Kaifeng, Henan 475004, PR China.
authors.forename: Rui
authors.initials: R
authors.lastname: Zheng
authors.affiliation: Henan Key Laboratory of Polyoxometalate Chemistry, Institute of Molecular and Crystal Engineering, College of Chemistry and Chemical Engineering, Henan University, Kaifeng, Henan 475004, PR China.
authors.forename: Xing
authors.initials: X
authors.lastname: Ma
authors.affiliation: Henan Key Laboratory of Polyoxometalate Chemistry, Institute of Molecular and Crystal Engineering, College of Chemistry and Chemical Engineering, Henan University, Kaifeng, Henan 475004, PR China. Electronic address: ljchen@henu.edu.cn.
authors.forename: Lijuan
authors.initials: L
authors.lastname: Chen
authors.affiliation: Henan Key Laboratory of Polyoxometalate Chemistry, Institute of Molecular and Crystal Engineering, College of Chemistry and Chemical Engineering, Henan University, Kaifeng, Henan 475004, PR China; State Key Laboratory of Structural Chemistry, Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences, Fuzhou, Fujian 350002, PR China. Electronic address: zhaojunwei@henu.edu.cn.
authors.forename: Junwei
authors.initials: J
authors.lastname: Zhao
keywords: Isopolytungstate; Photoluminescence; Polyoxometalate; Rare earth