Use of the TCNQF4 2- Dianion in the Spontaneous Redox Formation of [FeIII (L- )2 ][TCNQF4 ⋅- ].

The reaction of [FeII (L. )2 ](BF4 )2 with Li2 TCNQF4 results in the formation of [FeIII (L- )2 ][TCNQF4 . - ] (1) where L. is the radical ligand, 4,4-dimethyl-2,2-di(2-pyridyl)oxazolidine-N-oxide and TCNQF4 is 2,3,5,6-tetrafluoro-7,7,8,8-tetracyanoquinodimethane. This has been characterised by X-ray diffraction, Raman and Fourier transform infrared (FTIR) spectroscopy, variable-temperature magnetic susceptibility, Mössbauer spectroscopy and electrochemistry. X-ray diffraction studies, magnetic susceptibility measurements and Raman and FTIR spectroscopy suggest the presence of low-spin FeIII ions, the anionic form (L- ) of the ligand and the anionic radical form of TCNQF4 ; viz. TCNQF4 . - . Li2 TCNQF4 reduces the [FeII (L. )2 ]2+ dication, which undergoes a reductively induced oxidation to form the [FeIII (L- )2 ]+ monocation resulting in the formation of [FeIII (L- )2 ][TCNQF4 . - ] (1), the electrochemistry of which revealed four well-separated, diffusion-controlled, one-electron, reversible processes. Mössbauer spectroscopy and electrochemical measurements suggest the presence of a minor second species, likely to be [FeII (L. )2 ][TCNQF4 2- ].