A Reduced 2Fe2S Cluster Probe of Sulfur–Hydrogen versus Sulfur–Gold Interactions. (31st July 2015)

• Record Type: Journal Article
• Authors: Crouthers, Danielle J.; Ding, Shengda; Denny, Jason A.; Bethel, Ryan D.; Hsieh, Chung‐Hung; Hall, Michael B.; Darensbourg, Marcetta Y.
• Is Part Of: Angewandte Chemie. Volume 127:Number 38(2015)
• Page Start: 11254
• Page End: 11258
• Publication Date: 2015-07-31
• Subjects: Chemistry -- Periodicals; 540
• DOI: 10.1002/ange.201504574
• Languages: English
• ISSNs: 0044-8249

Abstract

<abstract abstract-type="main" xml:lang="en"> <title>Abstract</title> <p>The Ph₃PAu⁺ cation, renowned as an isolobal analogue of H⁺, was found to serve as a proton surrogate and form a stable Au₂Fe₂ complex, [(μ‐SAuPPh₃)₂{Fe(CO)₃}₂], analogous to the highly reactive dihydrosulfide [(μ‐SH)₂{Fe(CO)₃}₂]. Solid‐state X‐ray diffraction analysis found the two SAuPPh₃ and SH bridges in <italic>anti</italic> configurations. VT NMR studies, supported by DFT computations, confirmed substantial barriers of approximately 25 kcal mol⁻¹ to intramolecular interconversion between the three stereoisomers of [(μ‐SH)₂{Fe(CO)₃}₂]. In contrast, the largely dative SAu bond in μ‐SAuPPh₃ facilitates inversion at S and accounts for the facile equilibration of the SAuPPh₃ units, with an energy barrier half that of the SH analogue. The reactivity of the gold‐protected sulfur atoms of [(μ‐SAuPPh₃)₂{Fe(CO)₃}₂] was accessed by release of the gold ligand with a strong acid to generate the [(μ‐SH)₂{Fe(CO)₃}₂] precursor of the [FeFe]H₂ase‐active‐site biomimetic [(μ₂‐SCH₂(NR)CH₂S){Fe(CO)₃}₂].</p> </abstract>