Synthesis and structure of a novel blue luminescent coordination polymer possessing 3D network with mirror symmetry triple-interpenetrated sixteen-membered rings

A novel Cd(II) coordination polymer [Cd(bpdc)(H2O)]n 1 (4,4′-H2bpdc = 4,4′-biphenyldicarboxylic acid) with 3-D open frameworks has been hydrothermally synthesized by the reaction between 4,4′-biphenyldicarboxylic acid and Cd(NO3)2·4H2O. The structure of coordination polymer 1 was characterized by single-crystal X-ray diffraction analysis, IR spectroscopy and element analysis. The result of single-crystal X-ray diffraction analysis reveals that coordination polymer 1 exhibits novel 4-connected net with the point symbol of {42 · 84}. Two carboxylate ends of bpdc2− ligand link Cd(II) cations into a dinuclear cluster. Mirror symmetry triple-interpenetrated sixteen-membered rings of 12.11 Å × 19.16 Å form into 3-D open frameworks through connecting to the bpdc2− ligands. Coordination polymer 1 and 4,4′-H2bpdc both emit blue luminescence in DMSO solution and in the solid state, which can be attributed to ligand-centered π*→π transitions.