Annulation of a 1,3-dithiole ring to a sterically hindered -quinone core. Novel ditopic redox-active ligands.

The fused 1,3-dithiole spacer seems to be very suitable for the functionalization of sterically hindered -quinones with additional groups capable of coordination of metal ions and/or possessing a redox activity. An effective method for the synthesis of sterically hindered -quinones containing 1,3-diketonate, dinitrile and -quinone-methide functional groups at the periphery of the ligand has been developed. The novel compounds have rigid and conjugated structures and exhibit properties typical of -quinones.