Ferrocene‑o‑Benzosemiquinonato Tin(IV) Electron-Transfer Complexes

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