Catalytic Conversion of Monophenols to Ortho‐Quinones in a Tyrosinase‐Like Fashion: Towards More Biomimetic and More Efficient Model Systems1. Issue 8 (30th April 2013)

• Record Type: Journal Article
• Authors: Schottenheim, Julia; Fateeva, Natalie; Thimm, Wulf; Krahmer, Jan; Tuczek, Felix
• Is Part Of: Zeitschrift für anorganische und allgemeine Chemie. Volume 639:Issue 8/9(2013)
• Page Start: 1491
• Page End: 1497
• Publication Date: 2013-04-30
• Subjects: Chemistry, Inorganic -- Periodicals; Chemistry -- Periodicals; 540
• DOI: 10.1002/zaac.201300065
• Languages: English
• ISSNs: 0044-2313

Abstract

<abstract abstract-type="main" xml:lang="en"> <title>Abstract</title> <p>A new tyrosinase model based on the mononuclear copper(I) complex <bold>CuL_bzm1</bold> is synthesized and characterized. The ligand <bold>L_bzm1</bold> of this system contains a combination of an imine and a benzimidazole function which renders the system more biomimetic in comparison to the recently published <bold>L_py1</bold> model of tyrosinase (M. Rolff, J. Schottenheim, G. Peters, F. Tuczek, <italic>Angew. Chem. Int. Ed.</italic><bold>2010</bold>, <italic>122</italic>, 6583). As shown by UV/Vis and NMR spectroscopy, the <bold>CuL_bzm1</bold> complex catalytically mediates the conversion of the monophenol DTBP‐H to the <italic>o</italic>‐quinone DTBQ with a TON of 31. This reaction was also conducted in a stoichiometric fashion to get information about the involved intermediates and identify possible reasons for the observed increase in catalytic performance with respect to the <bold>L_py1</bold> system. DFT calculations were performed for the μ‐catecholato dicopper intermediate, compound <bold>4^bzm</bold>. These calculations indicate a mixed valent Cu^I‐semiquinone‐Cu^II structure, indicating that one‐electron transfer from the monohydroxylated substrate to the copper centers has already occurred at this stage.</p> </abstract>