The use of the TCNQF42-dianion in the spontaneous redox formation of [FeIII(L-)2][TCNQF4*-]

The reaction of [Fe-II(L-center dot)(2)](BF4)(2) with Li(2)TCNQF(4) results in the formation of [Fe-III(L-)(2)][TCNQF(4)(center dot-)] (1) where L-center dot is the radical ligand, 4,4-dimethyl-2,2-di(2-pyridyl)oxazolidine-N-oxide and TCNQF(4) 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, Mossbauer spectroscopy and electrochemistry. X-ray diffraction studies, magnetic susceptibility measurements and Raman and FTIR spectroscopy suggest the presence of low-spin Fe-III ions, the anionic form (L-) of the ligand and the anionic radical form of TCNQF(4); viz. TCNQF(4)(center dot-)center dot Li(2)TCNQF(4) reduces the [Fe-II(L-center dot)(2)](2+) dication, which undergoes a reductively induced oxidation to form the [Fe-III(L-)(2)](+) monocation resulting in the formation of [Fe-III(L-)(2)][TCNQF(4)(center dot-)] (1), the electrochemistry of which revealed four well-separated, diffusion-controlled, one-electron, reversible processes. Mossbauer spectroscopy and electrochemical measurements suggest the presence of a minor second species, likely to be [Fe-II(L-center dot)(2)][TCNQF(4)(2-)].