Synthesis, Structures, and Properties of Neutral and Radical Cationic S,C,C-Bridged Triphenylamines.

A structurally constrained S,C,C-bridged triphenylamine was synthesized, and the corresponding radical cation was obtained as a hexachloroantimonate by chemical oxidation. An X-ray crystallographic analysis revealed an almost planar structure for this radical cation, which thus represents the first example of a planar, para-unsubstituted triphenylamine radical cation analogue with a sulfur bridge. The electronic properties of the radical cation were examined by UV-vis-NIR and ESR spectroscopy as well as DFT calculations.