A Tetranuclear Mixed-Valence Manganese Complex of a Diimine Ligand Derived from 1,4-Diformyl-2,3-dihydroxybenzene: Synthesis, Structure, and Magnetic Properties

Humphrey L. C. Feltham; Rodolphe Clérac; Sally Brooker

doi:10.1071/CH09254

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A Tetranuclear Mixed-Valence Manganese Complex of a Diimine Ligand Derived from 1,4-Diformyl-2,3-dihydroxybenzene: Synthesis, Structure, and Magnetic Properties

Humphrey L. C. Feltham ^A , Rodolphe Clérac ^B ^C and Sally Brooker ^A ^D

+ Author Affiliations

- Author Affiliations

^A Department of Chemistry, University of Otago, PO Box 56, Dunedin, New Zealand.

^B CNRS, UPR 8641, Centre de Recherche Paul Pascal (CRPP), Equipe ‘Matériaux Moléculaires Magnétiques’, 115 avenue du Dr Albert Schweitzer, Pessac, F-33600, France.

^C Université de Bordeaux, UPR 8641, Pessac, F-33600, France.

^D Corresponding author. Email: sbrooker@chemistry.otago.ac.nz

Australian Journal of Chemistry 62(9) 1119-1123 https://doi.org/10.1071/CH09254
Submitted: 29 April 2009 Accepted: 6 June 2009 Published: 17 September 2009

Abstract

An acyclic hexadentate diimine ligand, H₄L¹, was prepared in situ in methanol by the condensation of 1,4-diformyl-2,3-dihydroxybenzene (1) with 2-aminoethanol, and complexed directly with two equivalents of Mn^II(OAc)₂·4H₂O or Mn^III(OAc)₃·2H₂O, or with one equivalent of each. All three of these one-pot reactions gave the mixed-valent tetrametallic complex [Mn^II₂Mn^III₂(L¹)₂(OAc)₂(solvents)₄], [2(solvents)₄]. An X-ray crystal structure determination on [2(MeOH)₄]·2MeOH revealed a centre of inversion in the middle of the complex. The four metal ions are in an almost planar array, sandwiched by two offset ligands which provide all of the equatorial donors, with the axial sites occupied by acetate ions and methanol molecules. The two manganese(II) ions are seven coordinate and centrally located, whereas the two manganese(III) ions are Jahn–Teller elongated octahedra and are located in the outer sites. Magnetic analysis of an air-dried sample, [2(MeOH)₂(H₂O)₂]·3H₂O, showed that weak antiferromagnetic interactions between the manganese ions dominate, resulting in a low ground spin state.

Acknowledgements

This work was supported by grants from the MacDiarmid Institute and the University of Otago. We also thank the European network MAGMANet (NMP3-CT-2005–515767), the University of Bordeaux, the CNRS, the Région Aquitaine for financial support.

References

A Tetranuclear Mixed-Valence Manganese Complex of a Diimine Ligand Derived from 1,4-Diformyl-2,3-dihydroxybenzene: Synthesis, Structure, and Magnetic Properties

Abstract

Acknowledgements

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