H-Bonding Interactions Induced Two Isostructural Cd(II) Metal-Organic Frameworks Showing Different Selective Detection of Nitroaromatic Explosives

摘要

Two luminescent Cd(II) metal organic frameworks (MOFs) were prepared from electron-rich pi-conjugated fluorescent ligands. They are isostructural with sq1 nets. Their strong luminescences can be quenched by a series of nitroaromatic explosives. Notably, MOF 1 shows highly selective and sensitive detection of 4-nitrophenol (4-NP), while MOF 2 exhibits good responses toward picric acid (PA) compared with other nitroaromatic explosives. This different order of quenching efficiency is because there are H-bonding interactions between MOF 1 and 4-NP, while MOF 2 lacks these H-bonding interactions. MOF 1 displays highly selective and sensitive detection of 4-NP with the high quenching constant (6.74 x 10(4)M(-1)) and low detection limit (34.48 ppb), which is better than those of known MOFs. MOF 1 and MOF 2 have highly sensitive and selective detection of 4-NP and PA in the practical application, respectively.