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(L_OEt)]·0.25H₂O and [(Pc)­Ln­(L_OEt)] (Ln³⁺ = Dy³⁺, Tb³⁺, Ho³⁺, and Gd³⁺; TPP = 5,10,15,20-tetraphenylporphyrinate; Pc = phthalocyaninate; L_OEt^– = [(η⁵-C₅H₅)­Co­(P­(=O)­(OEt)₂)₃]⁻) are synthesized on the basis of the tripodal ligand L_OEt^– 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