Unexpected stability of the iron(II) complex by an asymmetrical Schiff base from Fe(III): structure, magnetic and Mössbauer investigations

Dawit Tesfaye; Mamo Gebrezgiabher; Jonas Braun; Taju Sani; Sebastien Diliberto; Pascal Boulet; Nandakumar Kalarikkal; Christopher E Anson; Annie K Powell; Madhu Thomas

doi:10.1098/rsos.241334

Unexpected stability of the iron(II) complex by an asymmetrical Schiff base from Fe(III): structure, magnetic and Mössbauer investigations

R Soc Open Sci. 2025 Jan 8;12(1):241334. doi: 10.1098/rsos.241334. eCollection 2025 Jan.

Authors

Dawit Tesfaye^{1

2

3}, Mamo Gebrezgiabher^{1

2}, Jonas Braun⁴, Taju Sani^{1

2}, Sebastien Diliberto⁵, Pascal Boulet⁵, Nandakumar Kalarikkal⁶, Christopher E Anson⁴, Annie K Powell⁴, Madhu Thomas^{1

2}

Affiliations

¹ Department of Industrial Chemistry, College of Natural and Applied Sciences, Addis Ababa Science and Technology University, PO Box 16417, Addis Ababa, Ethiopia.
² Nanotechnology Center of Excellence, Addis Ababa Science and Technology University, PO Box 16417, Addis Ababa, Ethiopia.
³ Department of Chemistry, College of Natural Sciences, Salale University, PO Box 245, Fitche, Ethiopia.
⁴ Institute of Inorganic Chemistry (AOC), Institute of Nanotechnology (INT) and Institute for Quantum Materials and Technologies (IQMT), Karlsruhe Institute of Technology (KIT), Kaiserstr. 12, Karlsruhe 76131, Germany.
⁵ Institute Jean Lamour (IJL), UMR 7198, CNRS-Université de Lorraine, Nancy 54011, France.
⁶ School of Pure and Applied Physics, Mahatma Gandhi University, Kottayam, Kerala 686560, India.

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.

Keywords: Mössbauer spectroscopy; asymmetrical Schiff base; low spin Fe(II) complex.

Associated data

figshare/10.6084/m9.figshare.c.7577666