[FeFe]-Hydrogenase H-Cluster Mimics with Unique Planar μ-(SCH2)2ER2Linkers (E=Ge and Sn)

Hassan Abul-Futouh, Laith R. Almazahreh, Takahiro Sakamoto, Nhu Y.T. Stessman, Dennis L. Lichtenberger, Richard S. Glass, Helmar Görls, Mohammad El-Khateeb, Philippe Schollhammer, Grzegorz Mloston, Wolfgang Weigand

Research output: Contribution to journalArticlepeer-review

39 Scopus citations


Analogues of the [2Fe-2S] subcluster of hydrogenase enzymes in which the central group of the three-atom chain linker between the sulfur atoms is replaced by GeR2and SnR2groups are studied. The six-membered FeSCECS rings in these complexes (E=Ge or Sn) adopt an unusual conformation with nearly co-planar SCECS atoms perpendicular to the Fe-Fe core. Computational modelling traces this result to the steric interaction of the Me groups with the axial carbonyls of the Fe2(CO)6cluster and low torsional strain for GeMe2and SnMe2moieties owing to the long C−Ge and C−Sn bonds. Gas-phase photoelectron spectroscopy of these complexes shows a shift of ionization potentials to lower energies with substantial sulfur orbital character and, as supported by the computations, an increase in sulfur character in the predominantly metal–metal bonding HOMO. Cyclic voltammetry reveals that the complexes follow an ECE-type reduction mechanism (E=electron transfer and C=chemical process) in the absence of acid and catalysis of proton reduction in the presence of acid. Two cyclic tetranuclear complexes featuring the sulfur atoms of two Fe2S2(CO)6cores bridged by CH2SnR2CH2, R=Me, Ph, linkers were also obtained and characterized.

Original languageEnglish (US)
Pages (from-to)346-359
Number of pages14
JournalChemistry - A European Journal
Issue number2
StatePublished - Jan 5 2017


  • conformational analysis
  • density functional calculations
  • electrocatalysis
  • photoelectron
  • sulfur

ASJC Scopus subject areas

  • Catalysis
  • Organic Chemistry


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