Modulation of magnetic properties at room temperature: coordination-induced valence tautomerism in a cobalt dioxolene complex.
Witt A, Heinemann FW, Sproules S, Khusniyarov M (2014)
Publication Status: Published
Publication Type: Journal article
Publication year: 2014
Journal
Book Volume: 20
Pages Range: 11149-11162
Journal Issue: 35
Abstract
The valence-tautomeric six-coordinate complex [Co(tbdiox)2(4-papy)2] (1; tbdiox = redox-active 3,5-di-tert-butyl-o-dioxolene, 4-papy = 4-phenylazopyridine) was synthesized and its electronic structure examined. Whereas 1 shows regular thermally driven valence tautomerism in the solid state, it partially dissociates in solution to form the five-coordinate species [Co(tbdiox)2(4-papy)] (2) and free 4-papy. Species 1 and 2 exhibit different electronic structures-low-spin (ls) Co(III) and high-spin (hs) Co(II), respectively-in solution at room temperature and therefore different magnetic properties. Since 1 and 2 are in an equilibrium that is 4-papy-dependent, the magnetic moment of the solution species can be tuned by means of the ligand content. Thus, the concept of coordination-induced valence tautomerism (CIVT) has been introduced. The electronic structures of 1 and 2 as well as their CIVT were elucidated by X-ray crystallography, electrochemistry, titration experiments, and all variable-temperature SQUID susceptometry, NMR, EPR, and electronic absorption spectroscopy. The experimental findings are strongly supported by broken-symmetry DFT calculations. The magnetic exchange interactions in different types of valence-tautomeric cobalt complexes were explored computationally.
Authors with CRIS profile
Alexander Witt
Naturwissenschaftliche Fakultät
Frank Wilhelm Heinemann
Lehrstuhl für Anorganische und Allgemeine Chemie
Marat Khusniyarov
Department Chemie und Pharmazie
Involved external institutions
United Kingdom (GB)How to cite
APA:
Witt, A., Heinemann, F.W., Sproules, S., & Khusniyarov, M. (2014). Modulation of magnetic properties at room temperature: coordination-induced valence tautomerism in a cobalt dioxolene complex. Chemistry - A European Journal, 20(35), 11149-11162. https://dx.doi.org/10.1002/chem.201402129
MLA:
Witt, Alexander, et al. "Modulation of magnetic properties at room temperature: coordination-induced valence tautomerism in a cobalt dioxolene complex." Chemistry - A European Journal 20.35 (2014): 11149-11162.
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