Diacenaphtho[1,2-c:1′,2′-e]-1,2-dithiin: synthesis, structure and reactivity

Diacenaphtho[1,2-c:1′,2′-e]-1,2-dithiin 2 was synthesized in 23% yield by the reaction of acenaphthylene with elemental sulfur at 120 °C. This reaction also afforded either diacenaphtho[1,2-b:1′,2′-d]thiophene 1 or diacenaphtho[1,2-b:1′,2′-e]-dihydro[e]-1,4-dithiin 3 depending on the reaction time. Compound 2 was desulfurized and converted to 1 under UV–vis irradiation in a benzene solution. Reaction of 2 with Pt(COD)2 yielded the complex Pt(COD)(C24H12S2) 4 (COD=1,5-cyclooctadiene) by insertion of a Pt(COD) group into the S–S bond of 2. When heated, 4 was desulfurized and converted to 1 by elimination of a (COD)PtS grouping. Compounds 1–4 were characterized crystallographically.