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A Ferrocene–Peptide Conjugate as a Hydrogenase Model System
Author(s) -
de Hatten Xavier,
Bothe Eberhardt,
Merz Klaus,
Huc Ivan,
MetzlerNolte Nils
Publication year - 2008
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/ejic.200800566
Subject(s) - chemistry , hydrogenase , ligand (biochemistry) , ferrocene , active site , peptide , cysteine , stereochemistry , nuclear magnetic resonance spectroscopy , infrared spectroscopy , combinatorial chemistry , crystallography , enzyme , electrochemistry , organic chemistry , biochemistry , receptor , electrode
This work introduces a bis(cysteine) ligand to build a small peptidic model system of hydrogenase enzymes. Fe(C 5 H 4 CO–Cys–OMe) 2 (LH 2 ) has been employed as a chelate for an iron–carbonyl complex, which mimics two essential structural properties of the hydrogenase class of enzymes, namely the coordination of the iron–carbonyl core to peptide ligands and the presence of an electrochemical relay in spatial proximity. The treatment of LH 2 with Fe 3 (CO) 12 yields LFe 2 (CO) 6 ( 3a ), which is the first peptide‐coordinated iron hydrogenase active‐site model complex. Compound 3a was fully characterized spectroscopically ( 1 H NMR, 13 C NMR, IR and Mössbauer spectroscopy, mass spectrometry and elemental analysis). A single‐crystal X‐ray analysis confirms the proposed structure and reveals a staggered conformation of the Fe 2 (CO) 6 S 2 core. Fourier transform infrared (FTIR) spectroelectrochemistry reveals an electronic interaction between the peptide backbone and the iron–carbonyl cluster, but not with the ferrocene subsite. The introduction of this peptidic cysteine‐based ligand into hydrogenase model chemistry helps to confirm the proposed cofactor biosynthesis and understand the electronic interplay between the metal–carbonyl active site and the protein environment in this important class of enzymes.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)