title: Unprecedented {Fe14 }/{Fe10 } Polyoxotungstate-Based Nanoclusters with Efficient Photocatalytic H2 Evolution Activity: Synthesis, Structure, Magnetism, and Electrochemistry.
abstract: Novel Fe10 and Fe14 clusters [Rb9 Cs4 H37 Fe10 O34 (A-α-PW9 O31 )3 (OH)3 ]⋅36 H2 O (1) and [H3 Rb3 Fe14 (OH)12 (PO4 )6 (B-α-PW9 O34 )2 ]⋅21 H2 O (2) were synthesized and characterized in the solid state by single-crystal X-ray diffraction, IR spectroscopy, thermogravimetric analysis (TGA), and magnetic studies, and in solution by electrochemistry. Cluster 1 is a decameric Fe(III) polyanionic cluster encapsulating a cesium atom in the center. Cluster 2 is a unique tetradecanuclear Fe(III) sandwich structure with phosphate-linked units featuring two quasicubic Fe4 O4 moieties. Apparently, 2 has the highest nuclearity of all known Fe(III) sandwich-type polyoxometalate clusters. Clusters 1 and 2 also act as photocatalysts with platinum as cocatalyst for H2 evolution from light-driven water splitting. Changes in the cyclovoltammetric patterns with variations in pH were observed for 1 and 2, most likely due to intermolecular interactions among the high-nuclearity Fe(III) cluster cores and subsequent changes in the acid-base properties of the two reduced POMs. Magnetic studies provide evidence of antiferromagnetic interactions in 1 and 2. TGA showed that complexes 1 and 2 decompose between 580 and 590 °C.
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, P. R. China.
authors.forename: Vikram
authors.initials: V
authors.lastname: Singh
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, P. R. China.
authors.forename: Zhiyuan
authors.initials: Z
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, P. R. China.
authors.forename: Pengtao
authors.initials: P
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, P. R. China.
authors.forename: Dongdi
authors.initials: D
authors.lastname: Zhang
authors.affiliation: Department of Chemistry, The University of Reading, Whiteknights, Reading, RG6 6AD, UK.
authors.forename: Michael G B
authors.initials: MG
authors.lastname: Drew
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, P. R. China. niujy@henu.edu.cn.
authors.forename: Jingyang
authors.initials: J
authors.lastname: Niu
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, P. R. China.
authors.forename: Jingping
authors.initials: J
authors.lastname: Wang
keywords: cluster compounds; electrochemistry; iron; photocatalysis; polyoxometalates