A lanthanide luminescent sensor for the detection of 4-nitrophenol in aqueous media

The development of facile luminescent sensors for detecting nitrophenols in aqueous media is of great necessity for the safety of the environment and human health, as they are a class of widespread toxic organic pollutants that cause serious adverse effects upon consumption. Based on a new multidentate asymmetric ligand (H2L) in which salicylamide and 4-nitryl-salicylaldimine are spaced by 1,2-bis(2-ethoxy)ethyl, a new hydrostable lanthanide intercycle, [Tb2L2(NO3)2]center dot CH3CN (Tb-[2]c), was prepared to act as a new luminescent sensor for 4-NP in water media. Structural analysis indicated that two fully deprotonated L2- ligands in cis-configuration and mu 2-L-kappa 2O1:kappa O2:kappa O4:kappa N2:kappa O5 coordination mode were interlocked by two TbIII ions to render the emitted TbIII encapsulated by L2- for lessening non-radiative transitions. The excellent sensitizing capability of the ligand L2- to TbIII was ascertained by both experimental methods and theoretical calculations. The sensing exploration indicated that Tb-[2]c exhibited highly sensitive and selective recognition of 4-NP against other nitroaromatics in aqueous media. The recognition mechanism could be attributed to the internal filtration effect (IFE) mechanism when DFT calculations and accumulating experimental evidence were combined. We present herein a new hydrostable lanthanide intercycle, which could act as a new luminescent sensor for 4-NP in water media.

Automated summary

The development of facile luminescent sensors for detecting nitrophenols in aqueous media is crucial for environmental and human health safety. In this study, a new hydrostable lanthanide intercycle was prepared as a luminescent sensor for 4-NP in water media, showing highly sensitive and selective recognition abilities.