Organometallic sulfur complexes: reactivity of the hydrogen sulfide anion with cobaloximes

Abstract

The reaction of alkylcobaloxime [Co(dmgH)₂(CH₂CH₃)(py)] (1) (dmgH = the anion of dimethyl-glyoxime) with KSH in water solution resulted in the selective displacement of the pyridine axial ligand affording the derivative K[Co(dmgH)₂(CH₂CH₃)(SH)] (2). An ¹H–¹H EXSY experiment revealed that the substitution is reversible and occurs in a slow exchange regime. Attempts to grow crystals of the HS⁻ adduct led to isolation of a rare example of the unexpected trisulfido-bridged dinuclear complex K₂[Co₂(dmgH)₂(CH₂CH₃)₂(μ-S₃)]. It was shown that the glyoximato ligands provided the metal centre with a coordination environment quite robust to prevent decomposition and constitute a suitable platform for developing the chemistry of organometallic complexes bearing hydrogensulfido or oligosulfido ligands.