Cadmium－Organic Frameworks Constructed from a 1,8-Naphthalimide-Based Bispyridyl Ligand and 2-Substituted Benzene-1,4-Dicarboxylic Acids: Synthesis, Structures, Gas Adsorption, and Detection of Volatile Organic Compounds and Nitro Compounds

• Main Authors: LU, XIAO-MIN, 呂曉旻
• Other Authors: WU, JING-YUN
• Format: Others
• Language: zh-TW
• Published: 2018
• Online Access: http://ndltd.ncl.edu.tw/handle/g5bye5

碩士 === 國立暨南國際大學 === 應用化學系 === 106 === This work reports three cadmium-based fluorescent metal－organic frameworks (MOFs) constructed from imide-based bispyridyl ligand, N-(pyridin-4-ylmethyl)-4-(pyridin-4-yl)-1,8-naphthalimide (NI-mbpy-44), and aromatic dicarboxylate ligands. Compounds [Cd(Br-1,4-bdc)(NI-mbpy-44)]•H2O (1, Br-1,4-bdc = 2-bromobenzene-1,4-dicarboxylate), [Cd(NO2-1,4-bdc)(NI-mbpy-44)]•H2O (2, NO2-1,4-bdc = 2-nitrobenzene-1,4-dicarboxylate), and [Cd(NH2-1,4-bdc)(NI-mbpy-44)]•H2O (3, NH2-1,4-bdc = 2-aminobenzene-1,4-dicarboxylate) were synthesized from the hydro(solvo)thermal reactions of cadmium nitrate, NI-mbpy-44, and related 2-substituted benzene-1,4-dicarboxylic acids. Compounds 1 – 3 have similar crystal structures, which adopt a honeycomb-like 2D 63-layer structure, with two Cd2(NI-mbpy-44)2 (M2L2) macrocycles in the ortho positions of each hexagon of the layer structure. Two identical 2D layers interpenetrate each other in the way that the 2-substituted 1,4-bdc ligands thread through the M2L2 macrocycles to form a polyrotaxane-like 2D + 2D → 2D structures. Compounds 1 – 3 showed poor CO2 uptakes of 14.90, 18.12, and 14.58 cm3/g, respectively, at 195 K and p/po = 1, even if they are highly porous with porosities of 44.0, 44.9, and 47.5%, respectively. The toluene suspensions of compounds 1 and 2 exhibit strong fluorescence emissions, which would be quenched by different nitro compounds in different degrees. Among the chosen nitro compounds, aromatic nitro compounds exhibit remarkable fluorescence quenching (> 60%), especially 4-nitrophenol (4-NP) (> 99%). On the contrary, non-aromatic nitro compounds such as nitromethane (NM) and 2,3-dimethyl-2,3-dinitrobutane (DMNB) show only about 20–35% reduction in fluorescence intensity of the toluene suspensions. We have also examined the vapor-sensing ability of compounds 1 and 2 toward volatile nitro and organic compounds. The solid state fluorescence of compound 1 would be effectively reduced by 2-nitrophenol (2-NP), diethylamine (Et2NH), and aniline (C6H5NH2), while that of compound 2 would be quenched by 2-NP, 1,4-dinitrobenzene (1,4-DNB), NM, Et2NH, and C6H5NH2 significantly. Compounds 1 and 2 could be used to uptake volatile iodine (I2) molecules. After adsorbing iodine, the solid state fluorescence intensity of both compounds are reduced more than 80% in ten minutes, and the crystal color is also changed from yellow to brown. After releasing I2 molecules, compounds 1 and 2 can be reused to capture and detect volatile iodine as they exhibit 50% and 70% recovery, respectively, in fluorescence intensity.