Ferromagnetic manganese "cubes": from PSII to single-molecule magnets

Dalton Trans. 2010 May 28;39(20):4777-85. doi: 10.1039/b925248g.

Abstract

The reaction of Mn(O₂CMe)₂·2H₂O with Me-saoH₂ (Me-saoH₂ = 2-hydroxyphenylethanone oxime) in MeCN forms the complex [Mn(III)₄(Me-sao)₄(Me-saoH)₄] (1) in good yields. Replacing Me-saoH₂ with Naphth-saoH₂ (Naphth-saoH₂ = 2-hydroxy-1-napthaldoxime) in the presence of CH₃ONa forms the complex [Mn(III)₄(Naphth-sao)₄(Naphth-saoH)₄] (2) in low yields, while the reaction between Mn(ClO₄)₂·6H₂O, Et-saoH₂ (Et-saoH₂= 2-hydroxypropiophenone oxime) and NBu₄OH in MeCN gives the complex [Mn(III)₄(Et-sao)₄(Et-saoH)₄] (3) in moderate yields. All three tetrametallic cages exclusively contain Mn(III) centres arranged in a "cube"-like topology, in which the metal centres are connected by -N-O(oximate) groups. The magnetic properties of 1-3 are near identical, revealing the presence of only ferromagnetic interactions between the metal ions leading to high-spin ground states of S = 8. The complexes display frequency dependent out-of-phase signals in ac susceptibility studies and, in the case of 1 single-molecule magnetism has been observed by means of single-crystal hysteresis loop measurements.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Coordination Complexes / chemical synthesis
  • Coordination Complexes / chemistry
  • Crystallography, X-Ray
  • Magnetics*
  • Manganese / chemistry*
  • Molecular Conformation
  • Photosystem II Protein Complex / chemistry*
  • Photosystem II Protein Complex / metabolism

Substances

  • Coordination Complexes
  • Photosystem II Protein Complex
  • Manganese