Liu Jia-Hui, Jin Yi-Shu, Tang Jinkui, Liu Cai-Ming, Zhang Yi-Quan, Kou Hui-Zhong
Engineering Research Center of Advanced Rare Earth Materials (Ministry of Education), Department of Chemistry, Tsinghua University, Beijing 100084, China.
State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Renmin Street 5625, Changchun 130022, China.
Molecules. 2025 May 3;30(9):2043. doi: 10.3390/molecules30092043.
A mononuclear complex [Dy(phenN)(HL')]PF·CHCl (HL' = /-1,1'-binaphthyl-2,2'-diphenol) with local symmetry was synthesized. Structural determination shows that Dy was encapsulated within the coordination cavity of the neutral hexaaza macrocyclic ligand phenN, forming a non-planar coordination environment. The axial positions are occupied by two phenoxy groups of binaphthol in the form. The local geometry of Dy closely resembles a regular hexagonal bipyramid configuration. The axial Dy-O distances are 2.189(5) and 2.145(5) Å, respectively, while the Dy-N bond lengths in the equatorial plane are in the range of 2.524(7)-2.717(5) Å. The axial O-Dy-O bond angle is 162.91(17)°, which deviates from the ideal linearity. Under the excitation at 320 nm, the complex exhibits a characteristic emission peak at 360 nm, corresponding to the naphthalene ring. The AC susceptibility measurements under an applied DC field of 1800 Oe show distinct temperature-dependent and frequency-dependent AC magnetic susceptibility, typical of single-molecule magnetic behavior. The Cole-Cole plot in the temperature range of 6.0-28.0 K was fitted using a model incorporating Orbach and Raman relaxation mechanisms, giving an effective energy barrier of = 300.2 K. Theoretical calculations on complex reveal that the magnetization relaxation proceeds through the first excited Kramers doublets with a calculated magnetization blocking barrier of 404.1 cm (581.4 K).
合成了一种具有局域对称性的单核配合物[Dy(phenN)(HL')]PF·CHCl（HL' = /-1,1'-联萘-2,2'-二酚）。结构测定表明，Dy被包裹在中性六氮杂大环配体phenN的配位腔内，形成了一个非平面的配位环境。轴向位置被联萘酚的两个苯氧基以这种形式占据。Dy的局部几何形状与正六边形双锥构型非常相似。轴向Dy-O距离分别为2.189(5) Å和2.145(5) Å，而赤道平面内Dy-N键长在2.524(7)-2.717(5) Å范围内。轴向O-Dy-O键角为162.91(17)°，偏离了理想的线性。在320 nm激发下，该配合物在360 nm处呈现出一个特征发射峰，对应于萘环。在1800 Oe的外加直流场下进行的交流磁化率测量显示出明显的温度依赖性和频率依赖性交流磁化率，这是单分子磁行为的典型特征。在6.0-28.0 K温度范围内的Cole-Cole图使用包含Orbach和Raman弛豫机制的模型进行拟合，得到有效能垒 = 300.2 K。对该配合物的理论计算表明，磁化弛豫通过第一个激发的Kramers双峰进行，计算得到的磁化阻挡能垒为404.1 cm（581.4 K）。
