Synthesis and functionalization reactivity of Fe-thiocarbonyl and thiocarbyne complexes

The remarkable catalytic transformation of CO to liquid hydrocarbons by Fe and Co catalysts in the industrial Fischer-Tropsch process motivates interest in developing well-defined systems to model aspects of this chemistry. One of the most interesting potential intermediates in this chemistry is a terminally-bound, first row metal carbide, yet a molecular model of this species remains elusive. With this in mind, we targeted the synthesis of highly-activated Fe-thiocarbonyl complexes, as prospective precursors to S-functionalization, C–S bond cleavage, and carbide generation. Herein, we describe the synthesis of three Fe–CS complexes that can be alkylated to generate a series of terminal Fe-carbynes that could be characterized across three oxidation states. Strategies to access C–S bond scission from these species are discussed, including limitations that, thus far, have precluded the generation of a terminal Fe-carbide for this system.