Effect of Anions on the Self-Assembly of Cd(II)-Containing Coordination Polymers Based on a Novel Flexible Tetrakis(imidazole) Ligand

Thirteen Cd(II)-contailling Coordination polymers based on the novel tetradentate ligand tetrakis(imidazol-1-ylmethyl)methane (L), namely, [Cd-2(L)(2)(SO4)(2)(H2O)(2)]center dot 4H(2)O (1), [Cd(L)(H2O)(2)](NO3)(2) (2), [Cd(L)(Br)(2)]center dot H2O (3), [Cd(L)(0.5)(L-1)] (4), [Cd-5(L-2)(5)(H2O)(2)]center dot 6H(2)O (5), [CdL3(L)(0.5)] (6), [CdL4(L)(0.5)(H2O)]center dot H2O (7), [Cd-2(L-5)(2)(L)]center dot 2H(2)O (8), [Cd-3(L-6)(2)(L)]center dot 4H(2)O (9), [Cd-3(L-7)(2)(L)(H2O)(2)]center dot 2.5H(2)O(10), [Cd(HL8)(L)]center dot 0.75H(2)O(11),[Cd-7(L-9)(3)(mu(3)-OH)(2)(L)(2)]center dot 8H(2)O(12), [Cd-2(L-10)(L)(H2O)(2)]center dot H2O (13), where H2L1 = fumaric acid, H2L2 = adipic acid, H2L3 = 1,3-benzenedicarboxylic acid, H2L4 = 1,4-benzenedicarboxylic acid, H2L1 5 5-OH-1,3-benzenedicarboxylic acid, H3L6 = 1,3,5-benzenetricarboxylic acid, H3L7 = 1,2,3-benzenetricarboxylic acid, H3L8=1,2,4-benzenctricarboxylic acid, H4L9=1,2,4,5-benzenetetracarboxylic acid, and H4L10 = 4,4'-oxidiphthalic acid, have been synthesized under hydrothermal conditions. Compound L center dot 5H(2)O shows a novel three-dimensional (3D) (3,8)-connected supramolecular architecture with a unique (3.5(2))(2)(3(4).4(2).5(6).6(12).7(3).8) topology. Compounds 1-3 were isolated by the reactions of L with inorganic anions (SO42-, NO3-, Br-). Compound 1 displays a 4-connected PtS network, Compound 2 exhibits a 3D 4-connected zeolite ABW net, while compound 3 is a two-dimensional (2D) (4(4))-sql net. Compounds 4-8 were isolated by the reactions of L with organic dicarboxylate ligands. 4 exhibits a 2-fold interpenetrating alpha-Po net, while 5 shows a noninterpenctrating 3D framework. 6 shows a 3D (65-8) CdSO4-type framework, whereas compound 7 has a different 3D framework with (4.6(2).7(2).8)(4(2).6(2).7.8) topology. 8 shows a 2D layer structure, which is further extended into a 3D supramolecular framework by the hydrogen bonds. Compounds 9-11 have been obtained by the reactions of L with organic tricarboxylate ligands. In 9, the Cd(II) atoms are bridged by L and L-6 ligands to form a 3D structure. In 10, the trinuclear Cd(II) clusters are linked by the L and L-7 ligands to generate it chiral 3D alpha-Po structure. In 11, the Cd(II) centers are connected by the L ligands and the partially deprotonated HL8 ligand to yield a 2D layer structure. Compounds 12 and 13 were synthesized by the reactions of L with different organic tetracarboxylate ligands. In compound 12, the L-9 ligands link the Cd(II) centers to form a 3D Cd-L-9 framework, and the L ligands further stabilize the 3D structure. In compound 13, L-10 ligands coordinate to the Cd(II) toms in tetradentate mode to generate a 2D layer, which is further linked by L ligands to form a 3D framework. The structural differences of compounds 1-13 indicate that the presence of the different anions play an important role in the resulting structures of the coordination polymers. The infrared spectra and luminescent properties were also investigated for the compounds.