Portal de Periódicos da CAPES

A Ferrocene–Peptide Conjugate as a Hydrogenase Model System

2008; Wiley; Volume: 2008; Issue: 29 Linguagem: Inglês

10.1002/ejic.200800566

1099-0682

Xavier de Hatten, Eberhardt Bothe, Klaus Merz, Ivan Huc, Nils Metzler‐Nolte,

Metal complexes synthesis and properties

Abstract 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)