Linear Mn-3(II) and cubane Mn-4(II) carboxylate clusters derived from di-2-pyridyl ketone: Synthesis, characterization and magnetic properties

Constantinos C. Stoumpos, Nikolia Lalioti, Ian A. Gass, Konstantinos Gkotsis, Alexandros A. Kitos, Harikleia Sartzi, Constantinos J. Milios, Catherine P. Raptopoulou, Aris Terzis, Euan K. Brechin, Spyros P. Perlepes

Research output: Contribution to journalArticlepeer-review

Abstract

The employment of di-2-pyridyl ketone, (py)(2)CO, in manganese(II) benzoate chemistry is reported. The syntheses, crystal structures and spectroscopic (IR, EPR) characterization are described for [Mn-3(II) (O2CPh)(6){(py)(2)CO}(2)] (1), [Mn-3(II) (O2CPh)(6){(py)(2)CO}(2)] center dot 2MeCN (2 center dot 2MeCN) and [Mn-4(II) (O2CPh)(4){(py)(2)-C(OH)O}(4)] (3), where (py)(2)C(OH)O- is the monoanion of the gem-diol form of (py)(2)CO. Variable-temperature, magnetic susceptibility studies on 3 have also been performed. Complexes 1 and 2 center dot 2MeCN are linkage isomers. The trinuclear molecules of both complexes have a linear structure, with one eta(1):eta(2):mu(2) and two syn, syn- eta(1):eta(1):mu(2) PhCOz(2)(-) groups spanning each pair of Mn-II atoms. The terminal Mn-II atoms are each capped by one kappa N-2,N' (PY)(2)CO ligand in orange 1 and one kappa N-2,O (py)(2)CO molecule in the yellow isomer 2 center dot 2MeCN. The molecule of 3 has a cubane topology with the Mn-II centers and the deprotonated oxygen atoms from the eta(1):eta(3):eta(1):mu(3) ligands occupying alternate vertices of the cube. A terminal monodentate PhCO2- group completes a distorted octahedral coordination at each Mn-II atom. The IR data are discussed in terms of the coordination modes of the ligands that are present in the complexes. The X-band EPR spectra of powdered 1 and 2 at 4 K indicate that the populated spin states exhibit a zero-field splitting, while the spectrum of 3 at 18 K is consistent with the presence of magnetically interacting Mn-II atoms in the solid state. The magnetic properties of 3 in the 300-5 K range have been modelled with two J values, which reveal weak antiferromagnetic interactions within the molecule. Some suggestions have been made concerning the great stability of complex 3. (c) 2009 Elsevier Ltd. All rights reserved.

Original languageEnglish
Pages (from-to)2017-2025
Number of pages9
JournalPolyhedron
Volume28
Issue number9-10
DOIs
Publication statusPublished - 22 Jun 2009

Keywords

  • Di-2-pyridyl ketone metal complexes
  • Linkage isomers
  • Magnetic susceptibility data
  • Manganese(II) clusters
  • Manganese(II) cubanes
  • SINGLE-MOLECULE MAGNETS
  • TETRANUCLEAR MANGANESE(II) COMPLEXES
  • NEUTRON-SCATTERING SPECTRA
  • X-RAY
  • CRYSTAL-STRUCTURES
  • METAL-COMPLEXES
  • COORDINATION CHEMISTRY
  • BENZOATE CHEMISTRY
  • LINKAGE ISOMERS
  • ALKOXIDE CUBES

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