Syntheses, structures and luminescence of a series of Cd(II)-containing coordination polymers constructed from a long flexible bis-triazole ligand

Six novel Cd(II) coordination polymers based on 4,4'-bis(1,2,4-triazol-1-ylmethyl) biphenyl (btmb), namely, [Cd(btmb)(2)I-2](n) (1), [Cd(btmb)I-2](n) (2), {[Cd(btmb)(2)(NO3)(2)]center dot H2O}(n) (3), {[Cd(btmb)(2)(SCN)(2)]center dot 3H(2)O}(n) (4), {[Cd(btmb)(CH3COO)(2)(H2O)]center dot CH3CN}(n) (5) and [Cd(btmb)Cl-2(H2O)](n) (6) have been synthesized by the reactions of btmb with Cd(II) salts in the presence of different anions (I, NO3-, NCS , CH3COO or Cl ) under appropriate reaction conditions. The assemblies of btmb with CdI2 afford two different structures: two-dimensional (2D) rhombohedral grid layer network structure 1 and 2D layer structure 2 involved with one-dimensional (1D) linear cadmium chains. Treatment of btmb with Cd(NO3)(2)center dot 4H(2)O gives rise to a 2D grid network structure 3 which is similar to 1. When the I or NO3 anions were replaced by NCS , CH3COO or Cl , different 1D coordination polymers 4-6 were obtained, respectively. Polymer 4 displays a 1D double-chain structure, while both polymers 5 and 6 show 1D zigzag chain structures. In addition, the luminescence measurements reveal that polymers 1-6 exhibit different fluorescent emissions in the solid-state at room temperature, which can be attributed to the various coordination environments of Cd(II), solvent molecules and different packing interactions in these polymers. (C) 2010 Elsevier B.V. All rights reserved.