Slow magnetic relaxation behaviors and diamagnetic dilution studies of a carboxyl bridged dinuclear dysprosium(Ⅲ) complex  

作　　者：Wenting Liu Yibo Qiu Weiqin Xu Manli Cao Xin Deng Weiquan Lin 

机构地区：[1]School of Chemistry and Materials Science,Guangdong University of Education,Guangzhou,510303,China [2]School of Chemistry and Chemical Engineering/Institute of Clean Energy and Materials,Guangzhou University,Guangzhou,510006,China

出　　处：《Journal of Rare Earths》2024年第11期2088-2096,I0003,共10页稀土学报（英文版）

基　　金：Project supported by the National Natural Science Foundation of China (21805048,22005069);the Natural Science Foundation of Guangdong Province (2022A1515011145,2023A1515010602);the Science and Technology Research Project of Guangzhou (202102080023,202201020166);the Project for Key Areas of Ordinary Colleges and Universities of Guangdong Province(2022ZDZX4035);the "Climbing Program" Special Funds of Guangdong Province (pdjh 2023b0389)。

摘　　要：By using a rigid bulky carboxylic ligand a-cyanocinnamic acid(CCA),a dinuclear dysprosium(Ⅲ) complex [Dy_(2)(CCA)_(6)(MeOH)_(4)](1) was synthesized.Single crystal X-ray crystallography reveals that the two eight-coordinate dysprosium ions are bridged by four deprotonated carboxyl groups,forming a centrosymmetric paddle-wheel-1ike structure.Dynamic magnetic property measurements indicate that complex 1 displays field-induced slow magnetic relaxation.The temperature-dependent relaxation times can be fitted using Orbach and Raman processes with parameters of n=2.8(2),C=27(8) s^(-1)/K^(n),τ_(0)=5(2) × 10^(-10) s and U_(eff)=40(3) cm^(-1).Magnetic studies on the diamagnetic Y~Ⅲ-diluted analogue[Dy_(0.206)Y_(1.794)(CCA)_(6)(MeOH)_(4)](2) reveal its slow magnetic relaxation behavior without external dc field and the antiferromagnetic coupling between the Dy^(Ⅲ) ions in 1.Fits on the obtained relaxation times of 2lead to the parameters of n=4.5(3),C=0.7(2) s^(-1)/K^(n),τ_0=2.8(2) × 10^(-9) s and U_(eff)=38(2) cm^(-1).The results suggest that slow magnetic relaxation originates from the single-ion relaxation of Dy^(Ⅲ) ions.Moreover,the diamagnetic dilution can suppress other fast relaxation pathways at low temperature,on account of the elimination of magnetic coupling and dipolar interaction.Ab initio calculations were then performed on the single Dy^(Ⅲ) ion species {YDy} and indicate that the first excited Kramers doublets(KDs)lie at ca.76 cm^(-1),which is slightly higher than the experimental U_(eff) value.The intramolecular magnetic interactions were also calculated and indicate a weak ferromagnetic dipole-diploe magnetic interaction and an antiferromagnetic exchange coupling.

关 键 词：Single-molecule magnets Dilanthanide complexes Diamagnetic dilution Rare earths 

分 类 号：O641.4[理学—物理化学]