2,3-Pyrazine Dicarboxylate-Bridged Ln-based Arsenotungstates with Luminescent Properties

Three novel dimeric 2,3-pyrazindicarboxylate-modified multinuclear Ln-containing arsenotungstates, K18H46[Ln3(H2O)27(pzdc)2As3W30O113]2·80H2O [Ln = La3+ (1), Ce3+ (2), Pr3+ (3), H2pzdc = 2,3-pyridinedicarboxylic acid], were successfully acquired. The butterfly-like polyanion is composed of two equivalent [Ln3(H2O)27(pzdc)2As3W30O113]32– subunits, in which the subunit consists of three La3+ ions, two pzdc2– ligands and a [As3W30O113]27‒ cluster. The pzdc2– ligands not only bridge Ln3+ ions to form five-membered N–La–O–C–C heterocycle, but also directly chelate with W atoms to form the classic N–W–O–C–C penta-membered ring. The 1 and 2 manifest excellent characteristic emission peaks of ATs. And the emission spectrum of 3 reveals the characteristic peaks of Pr3+ ions in the near-infrared and the visible region.