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

Two 3-D zinc framework compounds, [Zn 6 (BTB) 4 (4,4'-bipy) 4 (H 2 O) 4 ]·9H 2 O (1) and [Zn 3 (BTB) 2 (4,4'-bipy) 2 (H 2 O) 2 ]· 5H 2 O (2) (H 3 BTB = 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 BTB 3- , 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.