Witt, A., Heinemann, F. W., Sproules, S. and Khusniyarov, M. M. (2014) Modulation of magnetic properties at room temperature: Coordination-Induced Valence Tautomerism (CIVT)in a cobalt dioxolene complex. Chemistry: A European Journal, 20(35), pp. 11149-11162. (doi: 10.1002/chem.201402129)
Full text not currently available from Enlighten.
Publisher's URL: http://dx.doi.org/10.1002/chem.201402129
Abstract
The valence tautomeric six-coordinate complex [Co(tbdiox)<sub>2</sub>(4-<i>papy</i>)<sub>2</sub>] <b>1</b> (tbdiox = redox-active 3,5-di-<i>tert</i>-buty-o-dioxolene; 4-<i>papy</i> = 4 phenylazopyridine) has been synthesized and its electronic structure examined. While in the solid state <b>1</b> shows a regular thermally driven valence tautomerism, it partially dissociates in solution to form the five-coordinate species [Co(tbdiox)<sub>2</sub>(4-<i>papy</i>)] <b>2</b> and free 4-<i>papy</i>. Species <b>1</b> and <b>2</b> reveal different electronic structures – low-spin (<i>ls</i>) Co<sup>III</sup> and high-spin (<i>hs</i>) CoII, respectively – in solution at room temperature and therefore different magnetic properties. Since <b>1</b> and <b>2</b> are in equilibrium that is 4-<i>papy</i> dependent, the magnetic moment of the solution species can be tuned by the ligand content. Thus the concept of Coordination-Induced Valence Tautomerism (CIVT) has been introduced. The electronic structures of <b>1</b> and <b>2</b>, and their CIVT have been 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. Insight into magnetic exchange interactions within different types of valence tautomeric cobalt complexes is explored computationally.
| Item Type: | Articles |
|---|---|
| Status: | Published |
| Refereed: | Yes |
| Glasgow Author(s) Enlighten ID: | Sproules, Dr Stephen |
| Authors: | Witt, A., Heinemann, F. W., Sproules, S., and Khusniyarov, M. M. |
| College/School: | College of Science and Engineering > School of Chemistry |
| Journal Name: | Chemistry: A European Journal |
| Journal Abbr.: | Chem. Eur J. |
| Publisher: | Wiley |
| ISSN: | 0947-6539 |
| ISSN (Online): | 1521-3765 |
University Staff: Request a correction | Enlighten Editors: Update this record
Altmetric
Altmetric