Dangling Thiyl Radical: Stabilized in [PPh4]2[(bdt)WVI(O)(μ-S)2CuI(SC6H4S•)]

The synthesis, crystal structure, and spectroscopic characterization of [PPh4]2[(bdt)W(O)(S2)Cu(SC6H4S•)] (3; bdt = benzenedithiolate) relevant to the active site of carbon monoxide dehydrogenase are presented. Curiously, in 3, the copper(I) benzenemonothiolate subcenter possesses a dangling thiyl radical that is stabilized by a disulfido-bridged oxo tungsten dithiolene core. The benzenedithiolate ligand, which is generally bidentate in nature, acts as a bidentate and also as a monodentate in 3. The formation of an unusual dangling thiyl radical has been magnetically and spectroscopically identified and has been supported by the density functional theory level of calculation.