New Synthetic Routes to a Disulfidodinickel(II) Complex: Characterization and Reactivity of a Ni₂(µ-η²:η²-S₂) Core

Activation of elemental sulfur by the monovalent nickel complex [PhTt^tBu]Ni(CO) [PhTt^tBu = phenyl{tris[(tert-butylmethyl)thio]methyl}borate] generates the disulfidodinickel(II) complex 2. This species is alternatively accessible via thermal decomposition of [PhTt^tBu]Ni(SCPh₃). Spectroscopic, magnetic, and X-ray diffraction studies establish that 2 contains a µ-η²:η²-S₂ ligand that fosters antiferromagnetic exchange coupling between the Ni^II ions. This observation is in contrast to the lighter congener, oxygen, which strongly favors the bis(µ-oxo)dinickel(III) structure. 2 oxidizes PPh₃ to SPPh₃ and reacts with O₂, generating several products, one of which has been identified as [(PhTt^tBu)Ni]₂(µ-S) (3).