Cis-1,4-cyclohexadienebisepisulphide complexes of chromium, molybdenum and tungsten carbonyls: the x-ray crystal structure of

The first metal carbonyl derivatives of a coordinated episulphide ring are reported. Two classes of complex have been obtained wherein the bisepisulphide behaves either as a bridging ligand between two metal pentacarbonyl moieties as in for example , or as a chelating ligand in a mononuclear metal pentacarbonyl complex such as , for which the X-ray crystal structure is reported.