Single‐Step Insertion of Sulfides and Thiolate into Iron Carbide‐Carbonyl Clusters: Unlocking the Synthetic Door to FeMoco Analogues

We report the one-step syntheses, X-ray structures, and spectroscopic characterization of synthetic iron clusters bearing inorganic sulfides or thiolate with interstitial carbide motifs. Treatment of historical iron-carbide-carbonyl clusters [Fe n ( μ n -C)(CO) m ] x ( n = 5,6; m = 15,16; x = 0,-2) with electrophilic sulfur sources (S 2 Cl 2 , S 8 ) results in the formation of several μ 4 -S 'dimers of clusters' ( 1 and 2 ), and moreover the iron-sulfide-(sulfocarbide) clusters 3 and 4 . The core 'carbide' motif in 3 and 4 is the sulfocarbide unit {C-S} 4- , which serves as a structural model for the proposed intermediate in the radical-SAM biogenesis of the M-cluster. Furthermore, the 'electrophilic sulfur' strategy has been extended to provide the first ever thiolato-iron-carbide complex: An analogous reaction with toluylsulfenyl-chloride (tolS-Cl) affords the cluster [Fe 5 ( μ 5 -C)(SC 7 H 7 )(CO) 13 ] - ( 5 ). The 'electrophilic sulfur donor' strategy described herein provides a breakthrough towards developing logical syntheses of biomimetic iron-sulfur-carbide clusters like FeMoco.