Formation of (η-Cyclopentadienyl)(1,2-ethylenedithiolato, 1,2-ethylenediselenolato, and 2-selenolatoethylenethiolato-S,Se)cobalt(III) Complexes in a One-Pot-Reaction of (η-Cyclopentadienyl)(1,5-cyclooctadiene or dicarbonyl)cobalt(I) with Alkyne and a Mixture of S8and Se8

Abstract A one-pot-reaction of (η-cyclopentadienyl)(1,5-cyclooctadiene or dicarbonyl)cobalt(I) with alkyne (diphenylacetylene and phenylacetylene) and a mixture of S8 and Se8 gives (η-cyclopentadienyl)(2-selenolatoethylenethiolato-S,Se)cobalt(III) complex in addition to the corresponding dithiolato and diselenolato complexes. When phenylacetylene was used as an alkyne, a (2-phenyl-2-selenolatoethylenethiolato-S,Se)cobalt(III) complex was formed preferentially rather than the (1-phenyl-2-selenolatothiolato-S,Se)cobalt(III) complex. The separation of the diselenolato and selenolatothiolato complexes from the dithiolato complex was successfully done by utilizing the difference in how these complexes form adducts with tributylphosphine. The dithiolato complexes have more negative reversible half-wave potentials (for reduction) than the diselenolato complexes; the selenolatothiolato complexes have intermediate half-wave potentials.