Three Cd(II) coordination polymers assembled by flexible 2,2′-azodibenzoic acid and N-donor auxiliary ligand: Structural diversities and luminescent properties

Hydrothermal reactions of Cd(OAc)(2) center dot 2H(2)O with 2,2'-azodibenzoic acid (H2L) and three N-donor ancillary ligands in MeOH/H2O at 120 degrees C gave rise to three cadmium(II) coordination polymers [CdL(bpy)](n) (1), {[Cd4L4(bPe)(H2O)(2)] center dot 2H(2)O}(n) (2) and [CdL(bPP)](n) (3) [bpy = 4,4'-bipyridine, bpe = 1,2-bis(4-pyridyl) ethylene, bpp = 1,3-bis(4-pyridyl)propane]. Structural analysis reveals that compound 1 possesses a novel three-fold interpenetrating diamondoid framework constructed by linking Cd centers with L and pillared bpy ligands. Compound 2 comprises a 3D network with a rare Schlafli symbol of (4(4)6(5)8(1)) (4(4)6(2)), the 3D structure is built from 2D [CdL2](n) nets and pillared bpe ligands. Compound 3 exhibits the same 66 topology with that of 1. Such a 3D architecture contains 1D helical [Cd(bpp)](n) chains and [CdL](n) chains along the a axis and b axis, respectively. The structural differences among 1-3 indicate that the N-donor ancillary ligands have significant effects on the formation of the final architectures. Photoluminescent properties of 1-3 in solid state were also investigated. (C) 2013 Elsevier B.V. All rights reserved.