One-dimensional La(III) coordination polymer displaying multi-responsive luminescence activities towards Fe3+, acetone and benzothiozoles

Through reaction of La(NO3)(3) with a flexible carboxylic acid ligand named 3,5-bis[(2-carboxyphenyl)oxy]benzoic acid (H3L) under solvothermal condition, the complex with the formula of [La(L)(DMF)(2)] (1) was obtained. One-dimensional chain of the complex was generated through the connection of binuclear units of La-2(COO)(4) across the flexible acid ligands. Luminescence results showed that different pollutants (Fe3+, acetone and benzothiophene organic compounds) could quench the luminescence of the blue emission of the complex in DMF with much low detection limit. Among several 2-substituted benzothiophene compounds, 2,2'-dithiobisbenzothiazole (DM) has a strongest binding constant of 10.8 x 10(4) M-1 and lowest detection limit of 0.332 mu M (0.110 ppm). All quenching effect was found within 15 s. The sensing mechanism was investigated through a series of experiments and theoretical calculation. Complex 1 could be employed as a mull-responsive chemsensor for detection of different pollutants with high sensitivity and fast response.

Automated summary

In this study, a new complex [La(L)(DMF)(2)] (1) was obtained through the reaction of La(NO3)(3) with a flexible carboxylic acid ligand under solvothermal condition, which showed high sensitivity in detecting different pollutants, especially benzothiophene compounds. The complex exhibited significant luminescence quenching effects towards various pollutants, with the compound DM having the strongest binding constant and lowest detection limit.