Synthesis and characterization of a novel lanthanum (III) complex with a di(2-picolyl)amine-based ligand endowed with fluorescent properties

In this work, 1-(1-benzyl-1H-1,2,3-triazol-4-yl)-N,N-bis(pyridin-2-ylmethyl)methanamine ( 1 ), a ligand belonging to the DPA family, was coordinated to La(III), yielding compound La-1 . The structural and spectroscopic properties of the complex were analyzed by experimental and theoretical methods. The structural characterization of La-1 was described by means of single-crystal X-ray diffraction (SC-XRD) and Hirshfeld surface analysis, allowing a detailed conformational investigation. The lowest-energy conformer obtained from DFT calculations conformationally agreed with the structure obtained by SC-XRD. 1 H NMR titration studies confirmed the formation of a stable complex in solution. Ligand 1 exhibited a sensitive fluorescence enhancement and ratiometric response to La(III) ions, indicating that 1 can be considered a first step towards the design of new tools for the detection of lanthanide metal ions in environmental chemistry. Nitrogen based heterocyclic compounds are very effective in metal coordination The use of click reaction open the way to complex structures embedding the triazole ring Lanthanum is the one of the most common rare earth metal used in industry Toxicity of lanthanum requires novel approaches for its detection and removal from the environment A combined solid/liquid state and computational approach is fundamental in understanding the properties of ligand-metal coordination (C) 2022 Elsevier B.V. All rights reserved.