The synthesis of complex compounds of 4 - [(2,4-dimethoxybenzyl) amino] benzoic acid (HL) with ions of samarium (III), europium (III), terbium (III), gadolinium (III) and dysprosium (III). According to the data of elemental analysis and thermogravimetry, the obtained complexes are hydrates of the composition LnL3 · nH2O, where n = 0-2. The area of their thermal stability is in the range from 100 ° С to 150 ° С. Electronic and infrared absorption spectra of the ligand and complexes with rare-earth metal ions have been measured. According to the IR spectra, the coordination of the ligand with the metal ion occurs at the carboxyl group. The carboxyl group is bidentate coordinated. To excite luminescence, a line of a mercury lamp with a wavelength of 248 nm was used.
The highest luminescence intensity is observed for the coordination compounds Eu3 +, Tb3 +, Sm3 +, and Dy3 +.