Synthesis of the cobalt analogues of Roussin’s red salt esters

Cobalt analogs of the Roussin’s red salt esters have been prepared by the reaction of organic thiol or selenol compounds with the readily prepared [Co(NO)2Cl]2. The compounds are unstable to light and decompose in ca. 1 week even in the dark at −78 °C. The IR spectra suggest that the compounds have C2v symmetry with the possibility of a folded Co2S2 rhombus about the S–S axis.