Thiocarbyl ligands via elimination of pentafluorobenzene at a diiron centre: crystal structures of [Fe2(CO)4{μ-SC(Ph)CH}(μ-dppm)] and [Fe2(CO)4{μ-SCHC(Ph)C(O)}(μ-dppm)]

Reaction of [Fe2(CO)6{μ-OC–C(Ph)CH2}(SC6F5)] with bis(diphenylphosphino)methane (dppm) at 110 °C affords the alkenyl complex [Fe2(CO)4(μ-HCCHPh)(μ-SC6F5)(μ-dppm)] together with the novel complexes [Fe2(CO)4{μ-SC(Ph)CH}(μ-dppm)] and [Fe2(CO)4{μ-SCHC(Ph)C(O)}(μ-dppm)] resulting from elimination of pentafluorobenzene. Both have been characterised crystallographically, the hydrocarbyl units acting as six-electron donors. The thioalkyne complex [Fe2(CO)4{μ-SC(Ph)CH}(μ-dppm)] exists as cis and trans isomers. Both are fluxional and interconvert at higher temperatures as shown by 2D NMR.