A new polymeric chain constructed from isopolyanions and lanthanide cations: Synthesis, crystal structure, and properties of (NH4)5[Ln(NO3)2(H2O)3][H2W12O40]·nH2O (Ln = Ce, Pr, Nd, Gd, Dy, Ho)

A series of 1:1 composite compounds prepared with the isopolyanions and lanthanide cations, (NH4)5[Ln(NO3)2(H2O)3][H2W12O40]·nH2O (Ln = CeIII (1); PrIII (2); NdIII (3); GdIII, n = 1 (4); DyIII (5); HoIII, n = 1 (6)) were synthesized at room temperature and characterized by single-crystal X-ray structural analysis, elemental analyses, IR spectra, thermogravimetry analyses and cyclic voltammetry. X-ray structural analysis reveals that these structures are isostructural: polyanions are bridged by Ln ions via the coordination of the bridging oxygen atoms and terminal oxygen atoms, forming a W–Ot′–Ln–Ob–W linkage; and through the W–Ot′–Ln–Ob–W linkage a one-dimension infinite linear chain with alternating cations and anions is formed. Compounds 1–6 represent the first example where two types of inorganic oxoanions (NO3− and [H2W12O40]6−) simultaneously coordinating to LnIII, in which the NO3− ions act as the bidentate ligands coordinating to the LnIII, forming a four-membered ring. The room temperature luminescent studies indicate that 3 exhibits strong luminescence in the near-IR region.

Graphical abstractA series of 1:1 composite compounds prepared with the isopolyanions and lanthanide cations, (NH4)5[Ln(NO3)2(H2O)3][H2W12O40]·nH2O (Ln = CeIII (1); PrIII (2); NdIII (3); GdIII, n = 1 (4); DyIII (5); HoIII, n = 1 (6)) were synthesized at room temperature. X-ray structural analysis reveals that these structures are isostructural: polyanions are bridged by Ln ions via the coordination of the bridging oxygen (O17) atoms and terminal oxygen (O1) atoms, forming a W–Ot′–Ln–Ob–W linkage; and through the W–Ot′–Ln–Ob–W linkage a one-dimension infinite linear chain with alternating cations and anions is formed. Compounds 1–6 represent the first example where two types of inorganic oxoanions (NO3− and [H2W12O40]6−) simultaneously coordinating to LnIII, in which the NO3− ions act as the bidentate ligands coordinating to the LnIII, forming a four-membered ring.Figure optionsDownload full-size imageDownload as PowerPoint slide