Ferrocene‑<i>o</i>‑Benzosemiquinonato Tin(IV) Electron-Transfer Complexes

The interaction of ferrocene with tin­(IV) <i>o</i>-benzosemiquinonato complexes in acetonitrile results in a reversible electron transfer (ET) from ferrocene to the redox-active ligand with the formation of electron-transfer complexes [(3,6-Cat)­SnBr₃]⁻[Cp₂Fe]⁺ (<b>1</b>) and [(3,6-Cat)­(3,6-SQ)­SnCl₂]⁻[Cp₂Fe]⁺ (<b>2</b>), where 3,6-Cat is the 3,6-di-<i>tert</i>-butyl-catecholate dianion and 3,6-SQ is the 3,6-di-<i>tert</i>-butyl-<i>o</i>-benzosemiquinonato radical anion. The ET process and the solvent effect in the system ≪ferrocene–<i>o</i>-benzosemiquinonato tin­(IV) complexes≫ were investigated on the basis of a combination of spectroscopic and X-ray diffraction methods. The molecular structures of <b>1</b> and <b>2</b> were confirmed by X-ray analysis. Complex <b>2</b> demonstrates the ferromagnetic coupling in the linear chain alternating ···D^+•A^–•D^+•A^–•··· motif.