The reactivity of the cyclic (alkyl) (amino) carbene (cAACMe) -stabilized CS2 adduct, the azolium-2-dithiocarboxylate cAACMe-CS2 (1), toward selected transition metal reagents is reported. Mono- or polynuclear (cluster) complexes (Fe (CO) 3 (cAACMe-CS2) (2), CrCp (cAACMe-CS2) 2 (3), Cr3 (cAACMe-CS2) 4 (CO) 3 (4), Re (cAACMe-CS2) 3Re2 (CO) 6 (μ2-Cl) 3 (5), and Ni2Br2 (cAACMe-CS2) 2 (cAACMe-CS3) NiBr3 (6) were prepared and characterized. Solid state structural analysis, cyclic voltammetry, and spectroscopy revealed that the coordinated ligands 1 adopt multiple formal redox states in these complexes, ranging from 0 to -2. The cAACMe-CS2 (1) ligands were observed in a range of different terminal or bridging bonding modes, which feature metal coordination either exclusively via the sulfur atoms (κS, κS'; μ2-κ2S, κ2S'; μ3-κ2S, κ2S') or, for 4, in addition, via the carbon atom of the CS2 group (μ2-κ2S, κ2S', κC). Furthermore, oxidative reaction conditions involving 1 led to C-S bond cleavage, which resulted in cyclic activation products (cAACMe) 2 (C2S3) (7) and (cAACMe) 2 (C2S3) Br3 (8), as well as the cAACMe-CS3 ligand in 6. These findings provide evidence for the ligand systems' unique adaptability and versatility in coordination modes as well as ligand redox states, proving carbene-CS2 adducts to be most promising candidates for future endeavors into transition metal redox or cluster chemistry.
Luff et al. (Tue,) studied this question.