Comparative Spectroscopic Studies of Iron(III) and Manganese(III) Salen Complexes Having a Weakly Coordinating Triflate Axial Ligand
Access this Article
We thoroughly compared spectroscopic and magnetic properties of mononuclear iron(III) and manganese(III) complexes with symmetric and nonsymmetrical salen ligands, in order to investigate the relation between spectroscopic properties and electronic structures. Magnetic susceptibility and dual-mode electron paramagnetic resonance data show the assignment of [Fe<sup>III</sup>(salen)(OTf)] and [Mn<sup>III</sup>(salen)(OTf)] as high-spin <i>S</i> = 5/2 and <i>S</i> = 2 electronic configurations, respectively, irrespective of the electron-donating properties and symmetry of the salen ligand. Further insights into electronic structures of central metal are obtained from <sup>2</sup>H NMR spectra of selectively deuterated complexes, in which [Fe<sup>III</sup>(salen)(OTf)] and [Mn<sup>III</sup>(salen)(OTf)] exhibit well-resolved paramagnetic NMR signals of quite different shift patterns, due to the presence or absence of the unpaired electron in the d<sub><I>x</I><sup>2</sup> - <I>y</I><sup>2</sup></sub> orbital expected for <i>S</i> = 5/2 iron(III) or <i>S</i> = 2 manganese(III) centers.
- Bulletin of the Chemical Society of Japan
Bulletin of the Chemical Society of Japan 85(9), 940-947, 2012
The Chemical Society of Japan