1,2,3-SELENADIAZOLES AS PRECURSORS TO CYCLOPENTADIENYLCOBALT DITHIOLENES AND 1,4-DITHIINS - MOLECULAR-STRUCTURES OF BIS(CYCLOOCTENO)-1,4-DITHIIN AND BIS(CYCLOOCTENO)-1,4-DISELENIN

Cycloocteno-1,2,3-selenadiazole (1) and cyclopentadienyldicarbonylcobalt (2) react in the presence of an excess of elemental sulfur to yield the dithiolene cyclopentadienyl(1,2-cyclooctenedithiolato)cobalt (3). Available evidence indicates that this reaction involves the intermediacy of a cobalt-alkyne complex. Compound 3 is the first example of a cyclopentadienylcobalt dithiolene bearing aliphatic substituents. Analogous reactions performed using only catalytic quantities of 2 provide high-yield syntheses of bis(cycloocteno)-1,4-dithiin (6) and bis(cycloocteno)-1,4-diselenin (7), whose structures have been determined by X-ray diffraction.