Iron Carbide-Sulfide Carbonyl Clusters.

Described is the preparation of the first iron carbide-sulfides. The cluster [FeC(CO)(SO)] ([2]), which is generated quantitatively from [FeC(CO)] ([1]), was O-methylated to give the sulfinite [2Me]. Demethoxylation of [2Me] with BF gave the face-capped octahedral cluster FeC(CO)(SO) (3). In solution, 3 spontaneously converted to the sulfide FeC(CO)(S) (4), an edge-fused double cluster with FeC and FeS subunits. Although 4 undergoes 1e reduction reversibly, 2e reduction (or base hydrolysis) of 4 gives closo-[FeC(CO)(S)] ([5]). The synthetic entries into the FeCS manifold may underpin the preparation of active-site analogues of the FeMoco and FeVco cofactors.