Syntheses, structures and luminescence of two cadmium entangled coordination polymers based on bis(imidazole) and biscarboxylate ligands

Two entangled coordination polymers [Cd-2(bib)(bdc)(2)](n) (1) and [Cd-2(bib)(bda)(2)](n) (2) were synthesized by the hydrothermal reaction (bib = 1,4-bis(2-methyl-imidazol-1-yl)butane, bdc = 1,2-benzenedicarboxylate, bda = 1,4-benzenediacetate). 1 exhibits an unusual 6-connected self-catenated 3D network based on Cd-2(COO)(2) dimer with the point symbol of (4(4)center dot 6(10)center dot 8). 2 exhibits a 3-fold interpenetrating 3D pcu network based on Cd-2(COO)(2) dimer. The different conformations of bib ligands (the anti-anti-anti conformation in 1 and gauche-anti-gauche conformation in 2) play the key role in the construction of different structures in 1 and 2. The luminescence and thermal stability were investigated. (C) 2015 Elsevier B.V. All rights reserved.