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.