Syntheses,
Structures, and Magnetic Properties of
seven-coordinate Lanthanide Porphyrinate or Phthalocyaninate Complexes
with Kläui’s Tripodal Ligand
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Abstract
A series of seven-coordinate mononuclear
lanthanide(III) complexes
of the general formula [(TPP)Ln(L<sub>OEt</sub>)]·0.25H<sub>2</sub>O and [(Pc)Ln(L<sub>OEt</sub>)] (Ln<sup>3+</sup> = Dy<sup>3+</sup>, Tb<sup>3+</sup>, Ho<sup>3+</sup>, and Gd<sup>3+</sup>; TPP = 5,10,15,20-tetraphenylporphyrinate;
Pc = phthalocyaninate; L<sub>OEt</sub><sup>–</sup> = [(η<sup>5</sup>-C<sub>5</sub>H<sub>5</sub>)Co(P(=O)(OEt)<sub>2</sub>)<sub>3</sub>]<sup>−</sup>) are synthesized on the basis of the
tripodal ligand L<sub>OEt</sub><sup>–</sup> 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
