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 ).

A Thermally Stable Magnesium Phosphaethynolate Grignard Complex.

The 2-phosphaethynolate (OCP) anion has found versatile applications across the periodic table but remains underexplored in group 2 chemistry due to challenges in isolating thermally stable complexes. By rationally modifying their coordination environments using 1,3-dialkyl-substituted N-heterocyclic carbenes (NHCs), we have now isolated and characterized thermally stable, structurally diverse, and hydrocarbon soluble magnesium phosphaethynolate complexes (, , and ), including the novel phosphaethynolate Grignard reagent (). The methylmagnesium phosphaethynolate and magnesium diphosphaethynolate complexes readily activate dioxane with subsequent H-atom abstraction to form [(NHC)MgX(μ-OEt)] [X = Me () or OCP ( and )] complexes.

Soluble, crystalline, and thermally stable alkali CO and carbonite (CO ) clusters supported by cyclic(alkyl)(amino) carbenes.

The mono- and dianions of CO (, CO and CO ) have been studied for decades as both fundamentally important oxycarbanions (anions containing only C and O atoms) and as critical species in CO reduction and fixation chemistry. However, CO anions are highly unstable and difficult to study. As such, examples of stable compounds containing these ions are extremely limited; the unadulterated alkali salts of CO (, MCO, MCO, M = alkali metal) decompose rapidly above 15 K, for example.