Abstract
The employment of di-2-pyridyl ketone, (py)2CO, in manganese(II) benzoate chemistry is reported. The syntheses, crystal structures and spectroscopic (IR, EPR) characterization are described for [Mn3II (O2CPh)6{(py)2CO}2] (1), [Mn3II (O2CPh)6{(py)2CO}2] · 2MeCN (2 · 2MeCN) and [Mn4II (O2CPh)4{(py)2C(OH)O}4] (3), where (py)2C(OH)O- is the monoanion of the gem-diol form of (py)2CO. Variable-temperature, magnetic susceptibility studies on 3 have also been performed. Complexes 1 and 2 · 2MeCN are linkage isomers. The trinuclear molecules of both complexes have a linear structure, with one η1:η2:μ2 and two syn, syn- η1:η1:μ2PhCO2 - groups spanning each pair of MnII atoms. The terminal MnII atoms are each capped by one κ2N,N′ (py)2CO ligand in orange 1 and one κ2N,Ο (py)2CO molecule in the yellow isomer 2 · 2MeCN. The molecule of 3 has a cubane topology with the MnII centers and the deprotonated oxygen atoms from the η1:η3:η1:μ3 ligands occupying alternate vertices of the cube. A terminal monodentate PhCO2- group completes a distorted octahedral coordination at each MnII 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 MnII 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.
Original language | English (US) |
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Pages (from-to) | 2017-2025 |
Number of pages | 9 |
Journal | Polyhedron |
Volume | 28 |
Issue number | 9-10 |
DOIs | |
State | Published - Jun 22 2009 |
Funding
This work was supported by the EPSRC and Leverhulme Trust (to E.K.B.), and by the Operation and Vocational II (EPEAEK II) and particularly the program PYTHAGORAS (Grant b. 365.037 to S.P.P).
Keywords
- Di-2-pyridyl ketone metal complexes
- Linkage isomers
- Magnetic susceptibility data
- Manganese(II) clusters
- Manganese(II) cubanes
ASJC Scopus subject areas
- Physical and Theoretical Chemistry
- Inorganic Chemistry
- Materials Chemistry