Two Zn(II) and Cd(II) Metal-Organic Frameworks with Mixed Ligands: Synthesis, Structure, Sorption and Luminescent Properties

Two new metal-organic frameworks (MOFs) [Cd-3(tib)(2)(BPT)(2)(H2O)(2)]center dot DMA center dot 6H2O (1) and [Zn2(tib)(HBTB)2(H2O)]center dot 2H2O (2) (tib=1,3,5-tris(1-imidazolyl)benzene, H3BPT=biphenyl-3,4',5-tricarboxylic acid, H3BTB=4,4',4 ''-benzene-1,3,5-triyl-tribenzoic acid, DMA=N,N-dimethylacetamide) were synthesized and characterized. Complex 1 is a 4-nodal three-dimensional (3D) framework with point symbol {8(3)}4{8(5).12}{8(6)}2, while 2 is a two-dimensional (2D) network to be joined together by hydrogen bonds to generate a 3D supramolecular structure. Gas/vapor adsorption and luminescence behavior of the two complexes were studied. It is meaningful that 1 and 2 can selectively adsorb CO2 over N-2, and MeOH over EtOH. Furthermore, 1 can selectively detect acetone through a fluorescence quenching mechanism in the organic solvents including MeOH, EtOH, 2-PA, CH3CN, DMF, DMA, THF, CHCl3, CH2Cl2 and acetone.