Download decanuclear mixed-valence manganese(ii, iii) isobutyrate cluster

DECANUCLEAR MIXED-VALENCE MANGANESE(II, III) ISOBUTYRATE CLUSTER OBTAINED BY
ULTRASONIC TREATMENT
DULCEVSCAIA Galina 1,2 , WICHER Barbara3
1
Institute of Applied Physics, Academy of Sciences of Moldova, Chisinau, Moldova
2
Institute of Chemistry, Academy of Sciences of Moldova, Chisinau, Moldova
3
Faculty of Chemistry, Adam Mickiewicz University, Poznan, Poland
Reviewer: BACA S., dr.
Keywords: manganese carboxylate, mixed-valent cluster, polynuclear complexes
The syntheses of polynuclear manganese complexes still remains a highly attractive field of investigations since
the discovery that Lis’s Mn(III/IV) complex [Mn12O12(OCCH3)16(H2O)4] behaves as a single-molecular magnet
(SMM). Application of flexible bulky organic ligands can lead to formation of coordination clusters with highnuclearity [1]. This type of complexes containing mixed-valence ions could exhibit magnetic properties. The new
neutral beetle-like decanuclear manganese compound [Mn10O2(O2CCH(CH3)2)18((HO2CCH(CH3)2)3(H2O)] (1) (Fig.
1) with a {MnII8MnIII2O2} core was resulted from processing of manganese(II) isobutyrate in the presence of
auxiliary organic ligand such as 2,2′-dipyridyl-monoxime by ultrasonic waves at room temperature.
Single crystal X-ray diffraction analysis showed that cluster 1 consists of ten manganese atoms held together by
two μ4-oxo and eighteen bridging isobutyrate groups. Twelve (CH3)2CHCO2 function as a tridentate ligand in
which one carboxylate O atom bridges two metal centers and other one O atom is coordinated to a third Mn atom,
whereas six other carboxylate groups bind in the usual μ2-bridging fashion. Three terminal isobutyrates adopt a
monodentate mode each being coordinated to one Mn atom. In 1, the Mn10 core consists of a central hexanuclear
unit containing two Mn(III) and four Mn(II) atoms, which are further bridged to four peripheral Mn(II) centers. The
distance between Mn(III) atoms is 2.779 Å and bond distances within sites μ4-O are enclosed in the range of 1.886 1.902 Å. Four inner Mn(II) ions and four outer Mn(II) ions posses a distorted octahedral geometry and the
distances MnO are within 2.079 - 2.288 Å.
Fig. 1. Molecular structure of [MnII8MnIII2O2(O2CCH(CH3)2)18(HO2CCH(CH3)2)3(H2O)].
Bibliography:
[1]. I.L. Malaestean, M. Speldrich, A. Ellern, S.G. Baca, M.D. Ward, P. Kogerler. Decanuclear manganese
isobutyrate cluster featuring MnII8MnIII2 core. Eur. J. Inorg. Chem. 2009, 4209-4212
Acknowledgement: This research was supported by the Swiss National Science Foundation (SCOPES IZ73Z0_1
27925).