Synthesis of o -benzoquinones annulated with 2-thioxo-1,3-dithiole-4,5-dithiolate fragment. Dioxolene ligands bearing non-planar geometry

A procedure has been developed for the annulation of a 2-(thi)oxo-1,3-dithiole-4,5-dithiolate fragment to 3,6-di- tert -butyl- o -benzoquinone. The resulting o -quinones have a significant asymmetry with respect to the plane of the chelate dioxolene site, which can be used in the targeted design of the coordination environment of metal ions in complexes. Isomeric manganese adducts containing dioxolene, carbonyl, and phosphine ligands, which differ in the location of the asymmetric o -quinone ligand, have been characterized by EPR spectroscopy.