A pure inorganic 2-D framework based on paradodecatungstate and Mn²⁺ ions: syntheses, structure, and properties

Abstract

A pure inorganic 2-D framework based on paradodecatungstate polyanions and [Mn(H₂O)_n]²⁺ (n = 2, 3) ions, Na₁₀{[Mn(H₂O)₃]₂[H₂W₁₂O₄₂]}{[Mn(H₂O)₃]₂[Mn(H₂O)₄][H₂W₁₂O₄₂]}·56H₂O (1), has been synthesized and characterized by IR spectra, UV–vis spectra, thermogravimetric analysis (TGA), single-crystal X-ray diffraction, and magnetic measurements. Single-crystal X-ray diffraction analysis indicates that [H₂W₁₂O₄₂]¹⁰⁻ in 1 is a tetradentate ligand and coordinates to four [(Mn(H₂O)₃]²⁺ cations through terminal oxygens to form manganese doubly bridged 1-D chains, which are further linked through [Mn(H₂O)₄]²⁺ ions into a 2-D layer. The catalytic activities of 1 are tested in the selective oxidation of benzyl alcohol to benzaldehyde with 30% aqueous H₂O₂ as oxidant in toluene, exhibiting 90% conversion and 93% selectivity. Magnetic studies indicate that weak antiferromagnetic couplings exist between the Mn(II) ions in 1.

Graphical abstract

The pure inorganic–inorganic hybrid represents an extended structure constructed from paradodecatungstate and transition metal ions and shows definite catalytic activities on the probe reaction of benzyl alcohol oxidation to benzaldehyde with H₂O₂.

Keywords:

• Polyoxometalate
• Paradodecatungstate
• Two-dimensional layer
• Catalytic oxidation
• Magnetic property

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by the National Natural Science Foundation of China [21373159]; the Education Commission of Shaanxi Province [14JK1015]; the Funded Projects of Independent Innovation of Northwest University Postgraduates [YZZ12034].