Dye Adsorption and Fluorescence Sensing Behaviour About Rare Earth-Indole Carboxylic Acid Complexes

Five rare earth-indole carboxylic acid complexes: [Eu(IAA)2(phen)2]·NO3 (1) (IAA = indole acetic acid, phen = o-phenanthroline); [Nd(IAA)2(phen)2]·NO3 (2); [Er(IBA)3(phen)](phen)·HNO3·H2O (3) (IBA = indole butyric acid); [Ce(IBA)3(phen)](phen)·HNO3·H2O (4); [Dy(IBA)3(phen)](phen)·HNO3·H2O (5) were synthesized and characterized. Then, we reported their properties as dye adsorption and fluorescence sensing for the first time. The fluorescence explorations demonstrated that complex 1 exhibits highly selective and sensitive sensing for nitro aromatic compounds with high sensitivity (1.49 × 107 M−1) and low detection limit (11.40 µM). Meanwhile, these complexes also exhibit stronger selective adsorption of dye molecules (MB and MG) in aqueous solution. This study provides new physical insights into the rational design of lanthanide complexes based on multifunctional materials. We firstly reported five lanthanide complexes and displayed fluorescence sensing and selective adsorption dye properties.