Cd(II)/Mn(II)/Co(II)/Ni(II)/Zn(II) Coordination Polymers Built from Dicarboxylic Acid/Tetracarboxylic Acid Ligands: Their Structural Diversity and Fluorescence Properties

Abstract

Six Cd(II)/Mn(II)/Co(II)/Ni(II)/Zn(II) coordination complexes are formulated as [Cd2(X2-)2(μ3-O)2/3]n (1), [Mn2(X2-)2(μ3-O)2/3]n (2), {[Co1.5(Y4-)0.5(4,4'-bpy)1.5(OH-)]·2H2O}n (3), {[Ni(X2-)(4,4'-bpy)(H2O)2]·4H2O}n (4), [Zn(m-bdc2-)(bebiyh)]n (5), and [Cd(5-tbia2-)(bebiyh)]n (6) (H2X = 3,3'-(2,3,5,6-tetramethyl-1,4-phenylene) dipropionic acid. H4Y = 2,2'-(2,3,5,6-tetramethyl-1,4-phenylene)bis(methylene) dimalonic acid, bebiyh = 1,6-bis(2-ethyl-1H-benzo[d]imidazol-1-yl)hexane, m-H2bdc = 1,3-benzenedicarboxylic acid, and 5-H2tbia = 5-(tert-butyl)isophthalic acid) were obtained by hydrothermal reactions and structurally characterized. Complexes 1 and 2 have a 6-connected 3D architecture and with several point symbols of (36·46·53). Complex 3 features a 5-connected 3D net structure with a point symbol of (5·69). Complex 4 possesses a 4-connected 2D net with a vertex symbol of (44·62). Complex 5 is a 3-connected 2D network with a point symbol of (63). Complex 6 is a (3,3)-connected 2D network with a point symbol of (63)2. In addition, complexes 1 and 4 present good photoluminescence behaviors. The electronic structures of 1 and 4 were investigated with the density functional theory (DFT) method to understand the photoluminescence behaviors.