Two Novel 3-D Zinc Compounds with Mixture Ligands of H3BTB and 4,4 '-Bipy: Crystal Structures, Blue Fluorescence and Single Point Energy Calculation

Abstract

Two 3-D zinc framework compounds, [Zn-6(BTB)(4)(4,4'-bipy)(4)(H2O)(4)]center dot 9H(2)O (1) and [Zn-3(BTB)(2)(4,4'-bipy)(2)(H2O)(2)]center dot 5H(2)O (2) (H3BTB = 1,2,3-benzenetricarboxylic acid, 4,4'-bipy = 4,4'-bipyridine), are obtained from the diffusion method and hydrothermal reaction respectively. Though 1 and 2 has the same coordination geometries of zinc atoms and coordination mode of BTB3-, their 2-D layers are different: mirror symmetric layers in 1; parallel ones in 2, further connecting by 4,4'-bipy into 3-D frameworks. The hydrothermal reaction of 2 results in a more stable 3-D framework than the one in 1, which is supported by the single point energy calculations. 1 and 2 show similar blue fluorescence at 417 nm, which can be assigned to LMCT.