Chiral six-coordinate Dy(iii) and Tb(iii) complexes of an achiral ligand: structure, fluorescence, and magnetism

• Published in: Dalton transactions : an international journal of inorganic chemistry 2017-10, Vol.46 (38), p.13035-13042
• Main Authors: Liu, Mei-Jiao, Yuan, Juan, Zhang, Yi-Quan, Sun, Hao-Ling, Liu, Cai-Ming, Kou, Hui-Zhong
• Format: Article
• Language: English
• ISSN: 1477-9226; 1477-9234
• DOI: 10.1039/c7dt02409f

Two new chiral six-coordinate lanthanide complexes (1 for Dy and 2 for Tb) have been synthesized using the achiral flexible ligand H L (2,2'-[1,2-ethanediylbis[(methylimino)methylene]]bis[4,5-dimethylphenol]). Both complexes crystallize in the chiral P1 group space, and the enantiomers [Zn(L)Cl] Dy·MeOH·0.5H O (Λ-1), [Zn(L)Cl] Dy·1.5H O (Δ-1), [Zn(L)Cl] Tb·1.5H O (Λ-2) and [Zn(L)Cl] Tb·H O (Δ-2) are isolated in the reaction. Three [Zn(L)Cl] anions coordinate to the central lanthanide ion using two phenoxo oxygen atoms of L , and the lanthanide ion has the coordination geometry of D . Complex 1 exhibits a field-induced slow magnetization relaxation, which is typical of a single-ion magnet (SIM). Ab initio calculations on complex 1 and studies on magneto-structural correlationship of six-coordinate Dy(iii) SIMs indicate that the small energy barrier of complex 1 might be related to the absence of a unique anisotropic axis for the regular octahedral coordination configuration of Dy(iii) and the high quantum tunneling gap between the ground states (m = ±15/2). Complex 2 displays green photofluorescence and triboluminescence.