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.

Six Cd(II)/Mn(II)/Co(II)/Ni(II)/Zn(II) coordination complexes are formulated as [Cd 2 (X 2- ) 2 ( μ 3 -O) 2/3 ] n ( 1 ), [Mn 2 (X 2- ) 2 ( μ 3 -O) 2/3 ] n ( 2 ), {[Co 1.5 (Y 4- ) 0.5 (4,4'-bpy) 1.5 (OH - )]·2H 2 O} n ( 3 ), {[Ni(X 2- )(4,4'-bpy)(H 2 O) 2 ]·4H 2 O} n ( 4 ), [Zn( m -bdc 2- )(bebiyh)] n ( 5 ), and [Cd(5-tbia 2- )(bebiyh)] n ( 6 ) (H 2 X = 3,3'-(2,3,5,6-tetramethyl-1,4-phenylene) dipropionic acid. H 4 Y = 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 -H 2 bdc = 1,3-benzenedicarboxylic acid, and 5-H 2 tbia = 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 (3 6 ·4 6 ·5 3 ). Complex 3 features a 5-connected 3D net structure with a point symbol of (5·6 9 ). Complex 4 possesses a 4-connected 2D net with a vertex symbol of (4 4 ·6 2 ). Complex 5 is a 3-connected 2D network with a point symbol of (6 3 ). Complex 6 is a (3,3)-connected 2D network with a point symbol of (6 3 ) 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.