Syntheses, Structures, and Magnetic Properties of seven-coordinate Lanthanide Porphyrinate or Phthalocyaninate Complexes with Kläui’s Tripodal Ligand

A series of seven-coordinate mononuclear lanthanide­(III) complexes of the general formula [(TPP)­Ln­(LOEt)]·0.25H2O and [(Pc)­Ln­(LOEt)] (Ln3+ = Dy3+, Tb3+, Ho3+, and Gd3+; TPP = 5,10,15,20-tetraphenylporphyrinate; Pc = phthalocyaninate; LOEt– = [(η5-C5H5)­Co­(P­(=O)­(OEt)2)3]−) are synthesized on the basis of the tripodal ligand LOEt– and either porphyrin or phthalocyanine ligands. All of the complexes are characterized by X-ray crystallography and by static and dynamic magnetic measurements. The Dy and Tb complexes show the field-induced slow relaxation of magnetization, and they are interesting seven-coordinate single-lanthanide-based SMMs. The magnetic relaxation properties of these double-decker sandwich complexes are influenced by the local molecular symmetry and are sensitive to subtle distortions of the coordination geometry of the paramagnetic lanthanide ions, such as metal-to-plane distances, plane center distances, and bending angles.本研究以三脚架配体LOEt⁻[(η⁵-C₅H₅)Co(P(=O)(OEt)₂)₃]⁻、5,10,15,20-四苯基卟啉根(TPP)以及酞菁根(Pc)为原料，合成了一系列通式为[(TPP)Ln(LOEt)]·0.25H₂O与[(Pc)Ln(LOEt)]的七配位单核稀土(III)配合物，其中Ln³+涵盖Dy³+、Tb³+、Ho³+及Gd³+。所有上述配合物均通过X射线晶体学以及静态与动态磁学测量完成了完整表征。镝配合物与铽配合物表现出场诱导的磁化慢弛豫行为，属于极具研究价值的七配位单稀土基单分子磁体(SMMs)。这类双层夹心型配合物的磁弛豫特性受局部分子对称性调控，且对顺磁性稀土离子配位几何的细微畸变极为敏感，相关畸变包括金属-平面间距、平面中心间距与弯曲角度。