Series of Organic–Inorganic Hybrid Rare Earth Derivatives Based on [MnV13O38]7– Polyoxoanion: Syntheses, Structures, and Magnetic and Electrochemical Properties

Abstract

A family of polyoxometalate compounds based on 1:13 polyoxoanions [MnV13O38]7–, organic molecules, and lanthanide cations, H[{La2(DMF)5(H2O)4}{MnV13O38}]·DMF·5H2O (1), H[{Ce2(DMF)2(H2O)7}{MnV13O38}]·0.5DMF·5.5H2O (2), H2[{K(H2O)2}2{Nd(DMF)(H2O)3}{MnV13O38}]·5H2O (3), H[{Ln2(C6H5NO2)3(H2O)6}{[MnV13O38}]·C6H5NO2·10H2O (Ln = La 4, Ce 5), and H2.5[{Pr(C6H5NO2)(H2O)3.5}{Pr0.5(H2O)2}{MnV13O38}]·0.5C6H5NO2·10H2O (6) (DMF = N,N-dimethylformamide; C6H5NO2 = isonicotinic acid), have been obtained utilizing a conventional method of aqueous solution and further characterized by elemental analysis, IR spectrum, UV spectrum, thermogravimetric analysis, and single-crystal X-ray diffraction. Compounds 1 and 2 exhibit a one-dimensional extended chain structure constructed by [MnV13O38]7– and lanthanide-organic coordination linkage, while compound 3 reveals three-dimensional (3D) open framework formed by polyoxoanion-lanthanide chains and potassium cations. Compounds 4–6 exhibit 3D supramolecular framework architectures based on [MnV13O38]7– polyoxoanions and lanthanide-organic coordination units. These compounds represent the first examples of extended organic–inorganic hybrids built up by [MnV13O38]7– building blocks and rare earth cations. The influences of the lanthanide contraction effect on the structural alterations from 1 to 3 and from 4 to 6 have been disscussed. The electrochemical and electrocatalytic properties for compounds 1–6 have been studied. Magnetic studies indicate that antiferromagnetic interactions exist in compounds 1–6.