Redox Convergent Synthesis and Reactivity of a Cobalt(III)‐Pentasulfido Compound
Sayan Atta, Amit Majumdar
Abstract
Abstract A new mononuclear cobalt(III)‐pentasulfido compound, [(L)Co(S 5 )] ( 3 ) has been synthesized by using a convergent redox reaction between elemental sulfur and two new cobalt(II)‐thiolato compounds, [(L)Co(SR)] (R=Ph, 2 a ; 2,6‐Me 2 ‐C 6 H 4 , 2 b ), which in turn were synthesized from a dimeric cobalt(II) complex, [(L) 2 Co 2 ] 2+ ( 1 ). Compound 3 features a low‐spin, diamagnetic, Co(III) center with a coordinated pentasulfido (S 5 2− ) chain and has no precedence in the literature. Compound 3 is highly stable towards reduction with a potential of −1.36 V (vs. Cp 2 Fe + /Cp 2 Fe) and gives back 1 upon chemical/electrochemical reduction. Reaction of 3 with phosphines yields back 1 and phosphine sulfides, while protonation of the coordinated S 5 2− chain in 3 leads to the formation of 1 , elemental sulfur and H 2 S. Finally, transfer of the coordinated S 5 2− chain in 3 to selected organic compounds, such as MeI, PhCH 2 Br and PhCOCl, for the generation of organopolysulfido compounds has been demonstrated.