Molybdenum–Iron–Sulfur Cluster with a Bridging Carbide Ligand as a Partial FeMoco Model: CO Activation, EPR Studies, and Bonding Insight

• DOI: 10.1021/jacs.4c17893
• Publication Date: 2025-03-21T01:23:12Z
• Authors: Linh N. V. Le; Tianyi He; Justin P. Joyce; Paul H. Oyala; Serena DeBeer; Theodor Agapie

Nitrogenase enzymes catalyze the reduction of N2 to NH3 at a complex Fe-M (M = Mo, Fe, or V) cofactor (FeMco), which displays eight metal centers and sulfide carbide bridges with MFe7S8C composition. The role unusual μ6-carbide ligand its effects on remain unclear. Here, we describe transfer MoFe3S3 cluster supported by bisphenoxide from previously reported terminal Mo yield pentametallic MoS3Fe3CMo composition, also bridging CO that resembles lo-CO form nitrogenase. This has an S 1/2 spin state amenable studies pulse EPR spectroscopy, revealing significantly larger 13C hyperfine interaction (aiso(13C) 12.5 MHz) than any observed for various states FeMoco studied thus far (|aiso(13C)| 0.89 2.7 MHz). report provides strategy synthesis carbide-containing iron–sulfur clusters relevant nitrogenase modeling, as well benchmarking information metal–carbon interactions methods.