Synthesis And Fluorescence Sensing Properties Of Metal-organic Frameworlis Material Based On Benzimidazole Groups

Metal-organic frameworks?MOFs?materials are an emerging class of crystalline porous materials,which are known as porous coordination polymers.metal-organic frameworks materials have obtained widely attentions in various fields,such as gas capture and storage,gas separation,catalysis,sensors,drug delivery and fluorescence.Luminescent MOF materials have attracted tremendous research interests in the last two decades.Because the functional sites?open metal sites,Lewis acidic/basic sites?within MOFs can serve specific recognition sites for the detection of different analytes,Therefore,it has great potential application value in optical sensing.In this paper,we selected four kinds of rigid benzimidazole derivatives ligands with highly conjugated?system to building new structure MOFs,and they exhibit excellent performance in the detection of fluorescent 4-nitroaniline and copper ions.We take 2,6-bis?benzimidazolyl?pyridine?H₂BBP?,2,2-bis-1H-benzimidazole?BiBzImH₂?and 1,3,5-Tri?1H-benzo[d]imidazol-2-yl?benzene?TBB?as organic ligand,and BDC?p-phthalic acid?,D-H₂cam?D-Camphoric acid?,H₂dhtp?2,5-dihydroxyterephthalic acid?as ancillary ligands.Hydrothermal method was employed to build new structure MOFs.1-4:Zn?H₂BBP??BDC?,Cd₂?H₂BBP?₂?BDC?₂?3H₂O,Cd₂?BiBzImH₂?₂?D-cam?₂ and Cd?TBB??dhtp?.All compounds display intense hydrogen bonds and?-?stacking interactions with high chemical and thermal stability,and exhibit excellent luminescence at room temperature.Cd₂?BiBzImH₂?₂?D-cam?₂?compound 3?showed a highly selective fluorescence quenching response to 4-nitroaniline and Cu²⁺ions in liquid suspension,which can be conveniently observed by the naked eye under UV light.This reveals Cd₂?BiBzImH₂?₂?D-cam?₂ has the potential as a multifunctional luminescence sensor for the detection of 4-nitroaniline and Cu²⁺.For Cd?TBB??dhtp??compound 4?,the strong emission of Cd?TBB??dhtp?was quenched efficiently by adding trace amounts of4-Nitroaniline,even in the presence of other structurally similar nitroaromatic compounds,which exhibited superior selectivity of Cd?TBB??dhtp?successfully applied for the detection of 4-nitroaniline in the mixed nitroaromatic explosive samples.