Assembly of three novel 2D frameworks with helical chains based on [H2W12O40] clusters and lanthanide - Organic complexes

Three novel polyoxotungstate-based rare earth compounds, (C₆H₅NO₂)Ln(H₂O)₅]₂H₂W₁₂O₄₀] · nH₂O (Ln = Ce³⁺ (1), Pr³⁺(2), n = 7; Nd³⁺ (3), n = 6), have been synthesized in aqueous solution and characterized by single-crystal X-ray diffraction, elemental analysis, IR spectra and TG analysis. The structural feature of compounds 1-3 is that the α-metatungstate cluster H₂W₁₂O₄₀]⁶⁻ anions are linked by the lanthanide (Ln) cation-organic coordination complexes, resulting in a two-dimensional (2D) structure with helical chains. The magnetic properties of compounds 1 and 2 have been studied by measuring their magnetic susceptibility in the temperature range 2-300 K, indicating the existence of spin-orbital coupling interactions and antiferromagnetic response. Furthermore, the electrochemical properties of 1-3 were studied.