Hydrothermal syntheses and characterization of three lanthanide coordination complexes constructed by 2,2′:6′,2″-terpyridine and 2,2′-biphenyldicarboxylic acid

Two 1D coordination polymers [Ln2(dpdc)3(tpy)2·H2O]n [Ln=Nd 1, Yb 2, H2dpdc=2,2′-biphenyldicarboxylic acid and tpy= 2,2′:6′,2″-terpyridine] and one dinuclear complex Er2(dpdc)2(Hdpdc)2(tpy)2 3 were obtained via hydrothermal reactions and determined by X-ray diffraction analysis. The crystal structure data of 1 and 2 revealed that two coordination polymers were isostructural and possessed a 1D chain framework consisting of eight-coordinated Ln(III) centers. In the asymmetric unit, the two Er(III) ions in 3 were both nine-coordinated and had similar coordination environments. The Er(III) ions were bridged by dpdc2− ligands into dinuclear structures. The complexes were also characterized by IR spectra and thermogravimetric analysis. The solid fluorescence of 1 and 3 was also investigated at room temperature.