A new photochromic-ligand-based luminescent coordination polymer as a MnO4- sensor with extremely high sensitivity and excellent selectivity

Photochromic materials have attracted considerable attention because of their promising applications. Herein, the first dihydroanthracene-based photochromic organic ligand 9,10-bis(di(pyridine-4-yl)methylene)-9, 10-dihydroanthracene (L) was successfully synthesized. Its photochromic mechanism has been elucidated. The photochromic organic molecule was first developed as a functional ligand to construct an LCP/LMOF-based sensor material {[Cd-1.5(L)(HOBA)(EtOH)(SO4)(H2O)]center dot 3H(2)O}(n) (1) (LCP/LMOF = luminescent coordination polymer/luminescent metal-organic framework; H(2)OBA = 4,4'-oxybisbenzoic acid; EtOH = ethanol). 1 exhibits a very rare 1D triple-chain architecture, and possesses good water stability and high sensing sensitivity to MnO4-. More importantly, 1' (1 after photochromism) exhibits extremely high sensitivity for detecting MnO4- in aqueous media. Its K-sv (quenching constant, 3.74 x 10(6) M-1) is neatly 28 and 8 times more than that of 1 (1.36 x 10(5) M-1) and the reported highest value (4.49 x 10(5) M-1) for MnO4- sensor materials, respectively. Moreover, 1' has excellent MnO4- sensing selectivity and stable sensing ability at different pH. Especially, 1' can recognize MnO4- in the presence of similar strong oxidized anions CrO42- and Cr2O72-. The MnO4- test paper is successfully developed as a convenient tool for practical application. The mechanisms behind the outstanding MnO4- sensing properties of 1' were studied as well.

Automated summary

A novel photochromic organic ligand was successfully synthesized and used to construct a sensor material with high sensitivity. By studying its photochromic mechanism and sensing properties, it was found that the material exhibited extremely high sensitivity and selectivity in detecting MnO4-.