Singh Vikram, Chen Zhiyuan, Ma Pengtao, Zhang Dongdi, Drew Michael G B, Niu Jingyang, Wang Jingping
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.
Department of Chemistry, The University of Reading, Whiteknights, Reading, RG6 6AD, UK.
Chemistry. 2016 Jul 25;22(31):10983-9. doi: 10.1002/chem.201601453. Epub 2016 Jun 27.
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.
合成了新型的Fe10和Fe14簇合物[Rb9 Cs4 H37 Fe10 O34 (A-α-PW9 O31 )3 (OH)3 ]⋅36 H2 O (1)和[H3 Rb3 Fe14 (OH)12 (PO4 )6 (B-α-PW9 O34 )2 ]⋅21 H2 O (2)，并通过单晶X射线衍射、红外光谱、热重分析（TGA）和磁性研究对其固态性质进行了表征，还通过电化学方法对其溶液性质进行了研究。簇合物1是一个十聚体Fe(III)聚阴离子簇合物，中心包裹着一个铯原子。簇合物2是一种独特的十四核Fe(III)夹心结构，具有磷酸盐连接单元，其特征是两个准立方Fe4 O4部分。显然，2是所有已知Fe(III)夹心型多金属氧酸盐簇合物中核数最高的。簇合物1和2还可作为光催化剂，以铂作为助催化剂，用于光驱动水分解制氢。观察到1和2的循环伏安图随pH值变化而变化，这很可能是由于高核Fe(III)簇核之间的分子间相互作用以及随后两种还原多金属氧酸盐酸碱性质的变化所致。磁性研究提供了1和2中反铁磁相互作用的证据。TGA表明配合物1和2在580至590 °C之间分解。
