Four Dinuclear and One-Dimensional-Chain Dysprosium and Terbium Complexes Based on 2‑Hydroxy-3-methoxybenzoic Acid: Structures, Fluorescence, Single-Molecule-Magnet, and Ab Initio Investigation

• Published in: Inorganic chemistry Vol. 59; no. 7; pp. 4414 - 4423
• Main Authors: Zhong, Li, Chen, Wen-Bin, Li, Xiao-Hui, OuYang, Zhi-Jian, Yang, Meng, Zhang, Yi-Quan, Gao, Song, Dong, Wen
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 06.04.2020
• ISSN: 0020-1669; 1520-510X
• DOI: 10.1021/acs.inorgchem.9b03555

The unique electronic configurations of lanthanide­(III) ions generate abundant electronic energy levels, resulting in the fantastic magnetic and optical multifunctional properties of lanthanide complexes. Here, 2-hydroxy-3-methoxybenzoic acid (H2MBA) was used to construct four Dy­(III) and Tb­(III) complexes containing two isostructural dinuclear complexes of [Ln2(HMBA)2(MBA)2(DMF)2(H2O)2]·6H2O [Ln = Dy (1), Tb (2); DMF = N,N-dimethylformamide] and two other isostructural beltlike one-dimensional-chain complexes of [NH4]­[Ln­(HMBA)4] [Ln = Dy (3), Tb (4)]. Fluorescence measurements reveal that H2MBA can sensitize Dy­(III) and Tb­(III) characteristic luminescence. Furthermore, complex 3 can emit white light under UV-light irradiation originating from a dichromatic mixture of a blue emission of H2MBA and a dominating yellow emission of Dy3+ ions. Magnetic susceptibility measurements show that two Dy­(III) complexes are single-molecule magnets with anisotropy barriers of 90(2) and 31(5) cm–1 for 1 and 3, respectively. The magnet–luminescence–structure correlations as well as relaxation pathways are investigated by ab initio calculations and fluorescent spectrometry.