Biradical with a polyfluorinated terphenylene backbone

A method was developed for the synthesis of perfluoro-1,1′:4′,1″-terphenyl by the reaction of chloroperfluorobenzene with zinc dust followed by the reaction of the resulting mixture of C 6 F 5 ZnCl and (C 6 F 5 ) 2 Zn with decafluorobiphenyl in the presence of KF. The reaction of perfluoro-1,1′:4′,1″-terphenyl with tert-butylamine in an autoclave gives the aminodefluorination product, 4,4″-bis( tert -butylamino)perfluoro-1,1′:4′,1″-terphenyl, and the oxidation of the latter with m -chloroperbenzoic acid affords a new stable nitroxide biradical 4,4″-bis( N - tert -butyl- N -oxylamino)perfluoro-1,1′:4′,1″-terphenyl in quantitative yield. The molecular and crystal structures of the diamine and the biradical were established by X-ray diffraction. According to the X-ray diffraction data, the planes of the paramagnetic moieties and the aromatic rings are significantly rotated with respect to each other, resulting in weak intramolecular exchange interactions between the paramagnetic centers.