Self-assembly of 3-D 4d–4f coordination frameworks based on pyridine-3,5-dicarboxylic acid: Syntheses, crystal structures and luminescence

The hydrothermal reactions of H2PDC, AgNO3 with Eu2O3 or Tb(NO3)3·6H2O gave rise to two novel three-dimensional 4d–4f heterometallic metal–organic coordination polymers, AgEu(PDC)2 (1) and AgTb(PDC)2 (2) (H2PDC = pyridine-3,5-dicarboxylic acid), and characterized by elemental analysis, IR, thermal analysis and single-crystal X-ray diffraction. Complexes 1 and 2 crystallize in the monoclinic system, P2/c space group; the structure determination reveal that both of them are isostructural and feature an unusual three-dimensional heterometallic network structure in which infinite lanthanide-carboxylate chains are linked by [Ag(PDC)2]3− metalloligands to form a mixed-metal coordination network. Moreover, the luminescent properties of two complexes have also been investigated at room temperature.