A Ytterbium Polymer Incorporating Ethyl-4,5-Imidazole-Dicarboxylate and Formate Coligand: Structure, Luminescent, and Magnetic Properties

摘要

A new lanthanide-organic coordination polymer incorporating both substituted imdazole dicar-boxylate and formate auxiliary ligand, namely {[Yb3(HEimda)4(μ2-HCOO) · 4H2O] · 2H2O}_n (I) (H3Eimda = 1H-2-ethyl-4,5-imidazole-dicarboxylic acid), has been prepared and was structurally characterized by elemental analysis, IR and X-ray diffraction. It crystallizes in the monoclinic system, space group of C2/c. The polymer I is built from two dimensional (2D) double decker networks based on the Ln4HEimda4 tetranuclear basic carboxylate as secondary building unit. The extensive hydrogen bonds extend the 2D lamellar network into a 3D supramolecular aggregate. The emission spectrum of polymer I exhibits ligand-to-metal charge-transfer luminescence. Variable-temperature magnetic susceptibility measurement reveals that the end to end bridging fashion of formate group results in the depopulation of the stark levels for a single Yb~(3+) ion and/or possible antiferromagntic interactions between Yb~(3+) ions within the carboxylato bridged dinuclear unit.