Structures, Single-Molecule Magnets, and Fluorescent Properties of Four Dinuclear Lanthanide Complexes Based on 4‑Azotriazolyl-3-hydroxy-2-naphthoic Acid

• Published in: Inorganic chemistry 2019-05, Vol.58 (9), p.5914-5921
• Main Authors: Xie, Shang-Fang, Huang, Li-Qian, Zhong, Li, Lai, Bi-Lin, Yang, Meng, Chen, Wen-Bin, Zhang, Yi-Quan, Dong, Wen
• Format: Article
• Language: English
• ISSN: 0020-1669; 1520-510X
• DOI: 10.1021/acs.inorgchem.9b00260

Four isostructural dinuclear lanthanide complexes based on 4-azotriazolyl-3-hydroxy-2-naphthoic acid (H3ATNA) and 3-hydroxy-2-naphthoic acid (H2NA) ligands, {[Ln2(HATNA)2­(HNA)2­(H2O)4]­·6DMF} (Ln = Dy (1), Tb (2), Sm (3), Eu (4); DMF = N,N-dimethylformamide) have been prepared and characterized by X-ray diffraction crystallography, dc/ac magnetic characterization, and fluorescent spectrometry. The crystallographic data reveal dinuclear lanthanide cores of complexes 1–4, bridged by phenoxo and μ1,3 carboxyl groups. Each nine-coordinated Ln­(III) ion is located in a slightly distorted monocapped square antiprism. The ligand of H3ATNA displays a unique antenna effect in complex 4. Complexes 1–3 display only two ligand-centered fluorescent emissive peaks around 450 and 600 nm, and complex 4 shows four characteristic Eu­(III)-centered emission bands at 593, 618, 653, and 698 nm under excitation at 348 nm. Complex 1 exhibits single-molecule magnet behavior that is rationalized through ab initio calculations.