Metal–organic coordination polymers based on dicarboxylate and a flexible bispyridyl ligand: Synthesis, structures, and photoluminescence

Three new transition metal–organic coordination polymers [Zn(bpp)(C4H4O4)]·1.2H2O 1, [Cd(bpp)2(H2O)2](C4O4)·8H2O 2 and [Cd(bpp)2(C4O4)]·H2O 3 have been synthesized from the reaction of d10 block metal, dicarboxylic acid with 1,3-bis(4-pyridyl)-propane (bpp). Structural analysis reveal that the Zn atoms in 1 are bridged by the succinate anions to generate helical chains, which are interlinked by bpp ligands to a 3D framework with Sra (42 · 63 · 8) topology. The CdN4O2 octahedras in 2 are bridged by a pair of bpp ligands to form 1D repeated rhomboid chains, which are assembled into 2D layer via the hydrogen bonds. The six-coordinated Cd2+ ions in 3 are bridged by the acetylenedicarboxylato ligand to form 1D zigzag chains, which are interconnected by bpp ligands to construct 3D metal–organic framework with a (48 · 67) topology. The fluorescent spectra of 1–3 indicate intraligand fluorescence emission upon irradiation.