A multifunctional metal-organic framework with μ3-OH- site for gas and vapor sorption and selective detection of nitrofurantoin

A porous 3D multifunctional Zn-MOF (1), namely {[Zn2.5(DDPP)(OH)(H2O)]•H2O•1.5DMF}n (H4DDPP = 3,5-di(2',5'-dicarboxylphenyl)pyridine, DMF = N,N-dimethylformamide) was solvothermally synthesized by the reaction of H4DDPP ligand and Zinc salts. 1 exhibits a high adsorption performance for N2 (246.2 cm3 g-1 at 77 K) and CO2 (116.1 cm3 g-1 at 273 K) as well as excellent selective separation for CO2/CH4 (V:V = 0.5:05) and CO2/CH4 (V:V = 0.05:0.95) with the selectivity coefficiens are 79.3 and 25.4 at 298 K and 1 bar, respectively. Meanwhile, 1 shows a great performance for H2O vapor sorption and the uptake amount of H2O vapor is 281.9 cm3 g-1 (at 298 K and P/P0 = 0.99), which is comparable to that reported in the literatures. Furthermore, 1 has excellent separation ability for H2O vapor in H2O/CH3OH mixed vapor and the selectivity of 1 for H2O/CH3OH (V:V = 0.1:0.9) and H2O/CH3OH (V:V = 0.05:0.95) is 254.6 and 94.9 at 298 K and 1 bar, repectively. More importantly, Grand Canonical Monte Carlo (GCMC) simulation shows that the reason for the good adsorption capacity of 1 for CO2 and H2O vapor is attributed to the pore structure of 1 and the interaction between the coordinated H2O molecules and μ3-OH- in 1 and CO2 or H2O molecule. In addition, 1 shows sensitive sensing ability for nitrofurantoin (NFT) and the detection limit (DL) was 5.3×10-8 M. Moreover, the fluorescence sensing mechanism of 1 for NFT can mainly be attributed to the competitive absorption between the absorption spectrum of NFT and the emission spectrum of 1, the weak interactions between μ3-OH- in 1 and NFT and photoinduced electron transfer from 1 to NFT.