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

The reaction of [FeII(L •)2](BF4)2 with Li2TCNQF4 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-tetracyano-quinodimethane. This has been characterised by x-ray diffraction, Raman and Fourier-transform infra-red (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 FeIII ion, the anionic form (L-­) of the ligand and the anionic radical form of TCNQF4; TCNQF4•-. Li2TCNQF4 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. Mossbauer spectroscopy and electrochemical measurements suggest the presence of a minor second species, likely to be [FeII(L•)2][TCNQF42-].