Synthesis, structure and properties of a new Sm(III) rare-earth metal coordination complex with 2,5-dihydroxy-terephthalic acid ligand

Abstract

A new Sm(III) coordination complex, [Sm(DHTA)₄(H₂O)₃]_n, was synthesized with 2,5-dihydroxyterephthalic acid (H₂DHTA) as ligand. The crystal structure and properties were characterized by single crystal X-ray diffraction, IR, elemental analysis and TGA analysis. The single-crystal X-ray diffraction analysis showed that Sm(III) ion is nine-coordinate with six oxygen atoms of four DHTA ligands and three oxygen atoms of three H₂O molecules, forming a tri-capped trigonal-prism configuration. The adjacent units of the complex are extended into a 3 D supramolecular network. In the IR spectrum of the complex, there are asymmetric and symmetric stretching vibrations of C = O of the carboxyl group. The complex has two weight loss steps in the TG plot. The complex’s UV-Vis absorptions at 400 and 261 nm are attributed to the DHTA. Furthermore, there is a fluorescent maximum emission at 476 nm, which is derived from the ligand. The fluorescence is attributed to the ligand-ligand charge transfer of the complex.

Keywords:

• 2,5-Dihydroxyterephthalic acid
• Sm(III) complex
• coordination complex
• fluorescent property
• crystal structure

Disclosure statement

The author(s) declare(s) there is no conflict of interest regarding the publication of this paper.

Data availability statement

The data used to support the findings of this study are included within the article.

Additional information

Funding

This work was supported by grants from the Education Department of Jilin Province (No.: JJKH20200771KJ, JJKH20200758KJ, JJKH20200761KJ).