Hydrogenation of a Tricobalt Carbide Evolves through Fischer-Tropsch Intermediates.

The Fischer-Tropsch (FT) process facilitates the stepwise hydrogenation of carbon monoxide wherein liquid fuels are constructed from surface-bound CHx intermediates. Molecular interrogation of the surface chemistry in FT is provided by the stepwise hydrogenation of the coordinatively unsaturated anionic tricobalt carbide cluster [(FtbsL)Co3(μ3-CHx)]- which affords each of the series [(FtbsL)Co3(μ-CHx)]- (x = 0: 1, 1: 1-H, 2: 1-H2, 3: 1-H3) enroute to the hydride cluster [(FtbsL)Co3(μ-H)]- (2). Isotope tracer studies employing the 13C-labeled carbide cluster [(FtbsL)Co3(μ3-13C)]1- (1*) and H2/D2 confirmed that the carbide ligand is released as methane as verified by headspace analysis (GC-MS) and 13C NMR. The solid-state structures, relative stabilities, and hydrogenation rates of all four CHx clusters were assessed to inform on the structures and dynamics of intermediates evolved during the Fischer-Tropsch process.