Two New Sandwich-Type Polyoxomolybdates Functionalized with Diphosphonates: Efficient and Selective Oxidation of Sulfides to Sulfones

Qiaofei Xu; Xiaopeng Sun; Feng Hu; Rong Wan; Vikram Singh; Pengtao Ma; Jingyang Niu; Jingping Wang

doi:10.3390/ma10101173

Two New Sandwich-Type Polyoxomolybdates Functionalized with Diphosphonates: Efficient and Selective Oxidation of Sulfides to Sulfones

Materials (Basel). 2017 Oct 13;10(10):1173. doi: 10.3390/ma10101173.

Authors

Qiaofei Xu¹, Xiaopeng Sun², Feng Hu³, Rong Wan⁴, Vikram Singh⁵, Pengtao Ma⁶, Jingyang Niu⁷, Jingping Wang⁸

Affiliations

¹ Henan Key Laboratory of Polyoxometalate Chemistry, Institute of Molecule and Crystal Engineering, College of Chemistry and Chemical Engineering, Henan University, Kaifeng 475004, China. xqf199408a@163.com.
² Henan Key Laboratory of Polyoxometalate Chemistry, Institute of Molecule and Crystal Engineering, College of Chemistry and Chemical Engineering, Henan University, Kaifeng 475004, China. sunxiaopeng2013@163.com.
³ Henan Key Laboratory of Polyoxometalate Chemistry, Institute of Molecule and Crystal Engineering, College of Chemistry and Chemical Engineering, Henan University, Kaifeng 475004, China. huf17@mails.tsinghua.edu.cn.
⁴ Henan Key Laboratory of Polyoxometalate Chemistry, Institute of Molecule and Crystal Engineering, College of Chemistry and Chemical Engineering, Henan University, Kaifeng 475004, China. wanrong1992@163.com.
⁵ Henan Key Laboratory of Polyoxometalate Chemistry, Institute of Molecule and Crystal Engineering, College of Chemistry and Chemical Engineering, Henan University, Kaifeng 475004, China. singhvikram001@gmail.com.
⁶ Henan Key Laboratory of Polyoxometalate Chemistry, Institute of Molecule and Crystal Engineering, College of Chemistry and Chemical Engineering, Henan University, Kaifeng 475004, China. mpt@henu.edu.cn.
⁷ Henan Key Laboratory of Polyoxometalate Chemistry, Institute of Molecule and Crystal Engineering, College of Chemistry and Chemical Engineering, Henan University, Kaifeng 475004, China. jyniu@henu.edu.cn.
⁸ Henan Key Laboratory of Polyoxometalate Chemistry, Institute of Molecule and Crystal Engineering, College of Chemistry and Chemical Engineering, Henan University, Kaifeng 475004, China. jpwang@henu.edu.cn.

Abstract

Two sandwich-type polyoxomolybdates Na₈[MO₂{Mo₂O₅(O₃PCH₃C(O)PO₃)}₂] (M = Ni²⁺ (1); Co²⁺ (2)) were synthesized by one-pot reaction of Na₂HPMo₁₂O₄₀·14H₂O, 1-hydroxy ethidene diphosphonic acid (HEDP=HOC(CH₃)(PO₃H₂)₂), and (1) NiCl₂/CoCl₂ (2). Compounds 1 and 2 were characterized by single crystal X-ray analysis, X-ray powder diffraction (XRPD), IR spectroscopy, ³¹P NMR spectra, UV-vis spectroscopy, and thermogravimetric analyses (TGA). Structural analysis reveals that 1 and 2 exhibit similar centrosymmetric structure, which consists of one transition metal (TM) ion sandwiched by two same subunits {Mo₂O₅(O₃PCH₃C(O)PO₃)}. The clusters 1 and 2 show efficient catalytic activities for oxidation of thioanisole. Moreover, they are catalytically selective for oxidizing thioanisole. Both resuable polyoxomolybdates 1 and 2 catalysts show good thermo- and hydrolytic stability. It is noted that compound 1 shows outstanding catalytic activity for oxidation of various sulfides to corresponding sulfones with 93-100% selectivity at 97-100% conversion in one hour under mild conditions, which is potentially valuable to the removal of organic sulfides.

Keywords: catalyst; oxidation of sulfides; polyoxomolybdates.