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Unexpected stability of the iron(II) complex by an asymmetrical Schiff base from Fe(III): structure, magnetic and
Dawit Tesfaye1,2,3, Mamo Gebrezgiabher1,2, Jonas Braun4
1Department of Industrial Chemistry, College of Natural and Applied Sciences, Addis Ababa Science and Technology University, PO Box 16417, Addis Ababa, Ethiopia.
Abstract:
The asymmetric Schiff base prepared in situ from ethylenediamine and pyridine-2-carboxaldehyde reacts with Fe(ClO4)3·6H2O to form the Fe(II) complex [FeL2](ClO4)2 with L = N,N-diethyl-N'-(pyridin-2-yl)methylene)ethane-1,2-diamine, where the Fe(III) starting material has been unexpectedly reduced to Fe(II). This complex was characterized by elemental analysis, infrared spectra, single crystal and powder X-ray diffraction measurements, variable temperature DC magnetic measurement and room temperature Mössbauer spectroscopy. The asymmetric ligand L coordinates in a tridentate fashion through its pyridyl, azomethine and amino nitrogen atoms, generating a distorted octahedral geometry around the central metal ion. Variable temperature magnetic studies and a Mössbauer measurement show that the iron is locked in the low spin Fe(II) states.
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