A viologen-derived luminescent material exhibiting photochromism, photocontrolled luminescence and selective detection of Cr2O72-in aqueous solution

Stable viologen-derived multifunctional smart materials exhibit widespread practical applications in many areas. In this study, a viologen-derived material with 4-fold interpenetrating diamondoid network, {[Cd(1,4-ndc) (cpbpy)]& sdot;2H2O}n, was successfully constructed based on asymmetrical N-(3-carboxyphenyl)-4,4 '-bipyridinium (cpbpy) and 1,4-naphthalenedicarboxylic acid (1,4-H2ndc). The compound shows reversible photochromic behavior under a xenon lamp, which are proved by UV-vis spectra and EPR characterizations. Moreover, the compound with good photoluminescence properties displays photocontrolled luminescence quenching behaviors. Owing to its good water stability, the compound is then applied in luminescence sensing for the detection of Cr2O72- in aqueous solution. The corresponding luminescence quenching constant for Cr2O72- is KSV = 4.33 x 104 M-1, and the detection limit is 3.66 mu M. Systematic investigations on the luminescence quenching mechanism suggest that the inner filter effect resulted in the selective detection of Cr2O72- . This study provides inspiration for the design and synthesis of target luminescent crystalline materials with rigid and asymmetric viologen-derived ligands.