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).

Abstract A series of 1:1 composite compounds prepared with the isopolyanions and lanthanide cations, (NH 4 ) 5 [Ln(NO 3 ) 2 (H 2 O) 3 ][H 2 W 12 O 40 ]· n H 2 O (Ln = Ce III ( 1 ); Pr III ( 2 ); Nd III ( 3 ); Gd III , n  = 1 ( 4 ); Dy III ( 5 ); Ho III , 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 (NO 3 − and [H 2 W 12 O 40 ] 6− ) simultaneously coordinating to Ln III , in which the NO 3 − ions act as the bidentate ligands coordinating to the Ln III , forming a four-membered ring. The room temperature luminescent studies indicate that 3 exhibits strong luminescence in the near-IR region.