The Synthesis Structures And Luminescent Properties Of Bismuth Coordination Compounds

The crystal engineering of metal-organic frameworks (MOFs) is of great interest due to their fascinating structures and potential applications in magnetism, luminescence, catalysis, gas storage and separation. However, most of the work has so far focused on the assembly of structures containing transition metal and lanthanide ions, while the main group elements, such as bismuth based coordination polymers are still less investigated. Generally, Bi ions have a strong tendency to coordinate to both O-and N-donors, the choice of ligands is critical to obtain Bi-organic coordination frameworks. Here we report the systematic syntheses of four Bi-organic coordination polymers under hydrothermal reactions. These compounds display different luminescence. Furthermore, the PXRD, TGA, UV-visible and IR spectra were also studied.1. Three new bismuth-organic compounds, namely, Bi(OH)(2,6-pdc)-H2O (1), Bi4(OH)4(2,6-pdc)4(H2O)3-H2O (2) and Bi5(OH)5(2,6-pdc)5(H2O)4-H2O (3)(2,6-H2pdc=pyridine-2,6-dicarboxylate) have been obtained by incorporating different Bi subunits as building blocks under hydrothermal conditions. Compound1contains dimeric{Bi2} units and these are further linked by2,6-pdc2-ligands into a2D net with36topology.(?) Compounds2-3display44net topology by using linear{Big} and{Bi10} as secondary building units (SBUs), respectively. Compounds1-3display yellow and blue luminescence, respectively.2. The first luminescent Bi-Cd-organic framework, Bi2Cd(2,6-pdc)4(H2O)2-H2O (4), has been synthesized by using bismuth (Bi) oxides and cadmium (Cd) salts as metal sources under hydrothermal conditions. The Bi3+and Cd2+ions are linked by2,6-pdc2-ligands to give a [Bi4Cd2(2,6-pdc)10]6-{Bi4Cd2} unit, which is further linked by2,6-pdc2- ligands to four neighbors to form2D layers. Furthermore, the adjacent2D layers are arranged into a3D supramolecular framework by π-π stacking interactions. Compound4emits blue light with a maximum peak at470nm and a shoulder at441nm when excited at324nm. Tunable and white light luminescence was obtained through the doping of different Ln3+ions into the Bi-Cd-organic framework.