Synthesis, Structures, Gas Adsorption, and Sensing of Volatile Organic Compounds and Nitro Compounds of Fluorescent Zinc and Cadmium Based Metal–Organic Frameworks

• Main Authors: SU, YI-MING, 蘇益民
• Other Authors: WU, JING-YUN
• Format: Others
• Language: zh-TW
• Published: 2018
• Online Access: http://ndltd.ncl.edu.tw/handle/4e7ry3

碩士 === 國立暨南國際大學 === 應用化學系 === 106 === Fluorescent metal－organic frameworks (MOFs) [Cd(NI-bapy-34)2]．DMF (1； NI-Hbapy-34 = N-(3-carboxyphenyl)-4-(pyridin-4-yl)-1,8-naphthalimide)，[Zn3(bpdc)3(NI-mbpy-34)]．DMF (2；NI-mbpy-34 = N-(pyridin-3-ylmethyl)-4-(pyridin-4-yl)-1,8-naphthalimide, H2bpdc = biphenyl-4,4′-dicarboxylic acid), and [Zn2(2,6-ndc)2(NI-mbpy-34)]．1.5DMAc．2MeOH．H2O (3; 2,6-H2ndc = naphthalene-2,6-dicarboxylic acid) were hydro(solvo)thermally synthesized. MOF 1 suits a 2-fold interpenetrated 3D porous structure with porosity of 16.6%. MOF 2 suits a 2-fold interpenetrated 3D pillared-layer framework of simple hexagonal packing with porosity of 47.8%. MOF 3 suits a 2-fold interpenetrated 3D pillar-layer framework of primitive cubic with porosity of 50.6%. The DMF suspensions of MOFs 1-3 exhibit noticeable fluorescence emissions, which would be effectively quenched by 2-NP (2-nitrophenol), 3-NP (3-nitrophenol), 4-NP (4-nitrophenol), 4NT (4-nitrotoluene), 1,4-DNB (1,4-dinitrobenzene) and 2,4-DNT (2,4-dinitrotoluene). On the contrary, NB (nitrobenzene), NM (nitromethane), and DMNB (2,3-dimethyl-2,3-dinitrobutane) did not show their ability to reduce the fluorescence intensity of these DMF suspensions. These results indicate that MOFs 1-3 might be useful fluorescence sensors for detection of aromatic nitro compounds. Solid-state fluorescence-quenching studies performed by vapor-sensing experiments show that remarkable fluorescence quenching responses were observed in the cases of 2-NP (31%) and Et2NH (67%) toward MOF 2 and 4-NP (50%), acetonitrile (32%), aniline (42%), Et2NH (78%), and DCM (63%) toward MOF 3. MOFs 2 and 3 can be used to uptake volatile iodine (I2) molecules, along with significant crystal color change from yellow to brown and fluorescence quenching of 40% and 90%, respectively, after 60 min adsorption. The I2 molecules can be released by immersing I2-loaded 2 and 3 in methanol, which show 93% and 35% recovery, respectively. Hence, MOF 2 is reusable for capture of volatile iodine. MOFs 1-3 do not adsorb N2 at 77 K, but capture CO2 with adsorption abilities of 43.3, 28.7, and 80.2 cm3/g, respectively at 195 K and P/P0 = 1. Interestingly, MOF 1 at 273 K and 298 K exhibited gate-opening effect to adsorb CO2; PXRD patterns confirm the structure transformation upon adsorbing CO2.