Syntheses, Structures and Properties of a Series of ZnII Complexes Constructed from a Tetrakis(imidazole) Ligand and Various Anions

Six new coordination polymers, namely, [Zn(L)](NO3)(2)center dot 3H(2)O (1), [Zn-2(L)(0.5)(HPO3)(2)]center dot H2O (2), [Zn-2(L)(L-1)(2)]center dot 3H(2)O (3), [Zn-2( L)(L-2)(2)]center dot 4.75H(2)O (4), [Zn-2(L)(L-3)(2)]center dot 3H(2)O (5), and [Zn-2(L)(L-4)]center dot 3H(2)O (6), where L = tetrakis(imidazol-1-ylmethyl) methane, H2L1 = oxalic acid, H2L2 = 1,3-benzenedicarboxylic acid, H2L3 = 5-OH-1,3-benzenedicarboxylic acid, and H4L4 = 4,4'-oxydiphthalic acid, were successfully synthesized under hydrothermal conditions. In compound 1, the L ligands connect the Zn-II ions to yield a 3D 4-connected 4.6(5) net with the free NO3- filling the channels. In compound 2, HPO32- anions and L ligands link the Zn-II centers to generate a pentanodal (3,4)-connected (4.6.8)(6(2).8)(6(2).8(4))(4.6.8(3).10)(8(4).10(2))(2) net. In compound 3, the Zn2L21 units are linked by the L ligands to form a 2D 63 network. In compound 4, the L and L2 ligands connect the Zn-II ions to form a 3D framework with (4.6(2).8(3))( 6(2).7(2).8(2))(4.6.7(3).8) topology. In compound 5, L ligands coordinate with the Zn-II centers to give a 2D binodal 4-connected layer with the Schlafli symbol of (5(5).8)(2)(5(4).6(2)), which are further consolidated by L-3 ligands. In compound 6, the Zn-II centers are connected by the L and L-4 ligands to form a 2D 4-connected 4(3).6(3) network. The structural differences in 1-6 suggest the importance of the anions in the construction of the coordination polymers. The compounds underwent thermogravimetric analysis, and the luminescent properties of the compounds were also investigated.