Isolation and Reactivity of Carbene-Stabilized Carbon Disulfide Radical Anions.

The reaction of CAAC-CS betaine (; CAAC = cyclic(alkyl)(amino)carbene) and alkali metal reductants under ambient conditions yields carbene-stabilized carbon disulfide radical anions as crystalline alkali metal salts. The radicals form multinuclear clusters featuring diverse metal sulfide and disulfide interactions, which promote unusual reductive coupling and cyclization of adjacent CS units to CS heterocycles (). The addition of crown ethers to sequesters the alkali cations and facilitates disulfide cleavage to yield stable [CAAC-CS] monomers ( and ).