An efficient dual-response luminescent metal-organic framework sensor constructed by new photochromic ligand

Photochromic materials have shown very promising applications. However, developing new photochromic materials remains a huge challenge. In this work, a new photochromic organic molecule, namely 6,13-bis(di(pyridin-4-yl)methylene)-6,13-dihydropentacene (L), has been successfully synthesized. Its photochromic mechanism has been elucidated. The dihydropentacene-based photochromic organic molecule was firstly applied as functional ligands to construct LMOF-based sensor {Zn(L)(TPA)center dot H2O}(n) (1; LMOF = luminescent metal-organic framework; H(2)TPA = terephthalic acid). 1 exhibits a three-dimensional (3-D) two-fold interpenetrated architecture, excellent stabilities, luminescent and photochromic properties. 1 can highly sensitively detect Cu2+ and MnO4- in aqueous medium by luminescent quenching effect. Notably, the quenching constants of 1' (1 after photochromism) towards Cu2+ and MnO4- are 6.4 and 6.5 times higher than those of 1, respectively, which demonstrates significantly enhanced sensing sensitivities for 1'. Furthermore, 1' can effectively identify MnO4- from similar strong oxidizing anions CrO42- and Cr2O72-. This dual-response luminescent sensor exhibits good recyclability, and its quenching sensing mechanisms have been discussed in detail. This work will contribute to the development of efficient photochromic luminescent sensors.

Automated summary

In this study, a new photochromic organic molecule was successfully synthesized and applied to the construction of a photochromic luminescent sensor. The sensor showed high sensitivity in detecting Cu2+ and MnO4- in aqueous medium and demonstrated good recyclability.