Intramolecular iron-mediated C-H bond heterolysis with an assist of pendant base in a [FeFe]-hydrogenase model. Academic Article uri icon


  • Although many metalloenzymes containing iron play a prominent role in biological C-H activation processes, to date iron-mediated C(sp(3))-H heterolysis has not been reported for synthetic models of Fe/S-metalloenzymes. In contrast, ample precedent has established that nature's design for reversible hydrogen activation by the diiron hydrogenase ([FeFe]-H2ase) active site involves multiple irons, sulfur bridges, a redox switch, and a pendant amine base, in an intricate arrangement to perform H-H heterolytic cleavage. In response to whether this strategy might be extended to C-H activation, we report that a [FeFe]-H2ase model demonstrates iron-mediated intramolecular C-H heterolytic cleavage via an agostic C-H interaction, with proton removal by a nearby pendant amine, affording Fe(II)-[Fe'(II)-CH-S] three-membered-ring products, which can be reduced back to 1 by Cp2Co in the presence of HBF4. The function of the pendant base as a proton shuttle was confirmed by the crystal structures of the N-protonated intermediate and the final deprotonated product in comparison with that of a similar but pendant-amine-free complex that does not show evidence of C-H activation. The mechanism of the process was backed up by DFT calculations.

published proceedings

  • J Am Chem Soc

altmetric score

  • 0.25

author list (cited authors)

  • Zheng, D., Wang, N., Wang, M., Ding, S., Ma, C., Darensbourg, M. Y., Hall, M. B., & Sun, L.

citation count

  • 32

complete list of authors

  • Zheng, Dehua||Wang, Ning||Wang, Mei||Ding, Shengda||Ma, Chengbing||Darensbourg, Marcetta Y||Hall, Michael B||Sun, Licheng

publication date

  • December 2014