Manipulation of the Coordination Geometry along the C4 Rotation Axis in a Dinuclear Tb3+ Triple-Decker Complex via a Supramolecular Approach

Keiichi Katoh, Nobuhiro Yasuda, Marko Damjanović, Wolfgang Wernsdorfer, Brian K. Breedlove, Masahiro Yamashita

Research output: Contribution to journalArticle

Abstract

A supramolecular complex (1⋅C60) was prepared by assembling (C60-Ih)[5,6]fullerene (C60) with the dinuclear Tb3+ triple-decker complex [(TPP)Tb(Pc)Tb(TPP)] (1: Tb3+=trivalent terbium ion, Pc2−=phthalocyaninato, TPP2−=tetraphenylporphyrinato) with quasi-D4h symmetry to investigate the relationship between the coordination symmetry and single-molecule magnet (SMM) properties. Tb3+-Pc triple-decker complexes (Tb2Pc3) have an important advantage over Tb3+-Pc double-decker complexes (TbPc2) since the magnetic relaxation processes correspond to the Zeeman splitting when there are two 4f spin systems. The two Tb3+ sites of 1 are equivalent, and the twist angle (φ) was determined to be 3.62°. On the other hand, the two Tb3+ sites of 1⋅C60 are not equivalent. The φ values for sites Tb1 and Tb2 were determined to be 3.67° and 33.8°, respectively, due to a change in the coordination symmetry of 1 upon association with C60. At 1.8 K, 1 and 1⋅C60 undergo different magnetic relaxations, and the changes in the ground state affect the spin dynamics. Although 1 and 1⋅C60 relax via QTM in a zero applied magnetic field (H), H dependencies of the magnetic relaxation times (τ) for H>1500 Oe are similar. On the other hand, for H<1500 Oe, the τ values have different behaviors since the off-diagonal terms ((Formula presented.)) affect the magnetic relaxation mechanism. From temperature (T) and H dependences of τ, spin-phonon interactions along with direct and Raman mechanisms explain the spin dynamics. We believe that a supramolecular method can be used to control the magnetic anisotropy along the C4 rotation axis and the spin dynamic properties in dinuclear Ln3+-Pc multiple-decker complexes.

Original languageEnglish
Pages (from-to)4805-4815
Number of pages11
JournalChemistry - A European Journal
Volume26
Issue number21
DOIs
Publication statusPublished - 2020 Apr 9

Keywords

  • coordination modes
  • fullerenes
  • magnetic properties
  • single-molecule magnets
  • spin dynamics
  • supramolecular chemistry

ASJC Scopus subject areas

  • Catalysis
  • Organic Chemistry

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