Magnesium-stabilised transition metal formyl complexes: structures, bonding, and ethenediolate formation Joseph M. Parr and Mark R Crimmin Department of Chemistry, Imperial College London, UK. jmp20@ic.ac.uk, @josephmparr
Transition metal formyl complexes are important intermediates in the reduction of carbon monoxide (CO) and carbon dioxide (CO2). For example, transition metal formyl species have been proposed as key intermediates in the reduction of CO with H2 to form linear alkanes in the Fischer–Tropsch (F–T) process. Despite their importance, the detailed study of transition metal formyl complexes has been hampered by their low stability. Herein we report the first comprehensive series of crystallographically characterised transition metal formyl complexes. In these complexes, the formyl ligand is trapped as part of a chelating structure between a transition metal (Cr, Mn, Fe, Co, Rh, W, and Ir) and a magnesium (Mg) cation. Calculations suggest that this bonding mode results in significant oxycarbene-character of the formyl ligand. Further reaction of a heterometallic Cr–Mg formyl complex results in a rare example of C–C coupling and formation of an ethenediolate complex. DFT calculations support a key role for the formyl-intermediate in ethenediolate formation. These results show that well-defined transition metal formyl complexes are potential intermediates in the homologation of carbon monoxide.
P15
© The Author(s), 2022
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