Recent advances in dinuclear copper complexes as mimics of the catalytic centers of tyrosinase and catechol oxidase allowed the reproduction of the structural and mechanistic aspects of the enzymes. However, a challenging objective is the development of chiral complexes for bioinspired enantioselective oxidation reactions. Here, we report the synthesis and characterization of a dinuclear copper(II) complex with a new chiral diamino-m-xylenetetra(benzimidazole) ligand (L55Bu4), which has chiral centers at the four 2-methylbutyl substituents of the benzimidazole rings. The spectral characteristics, ligand binding properties, and reactivity of [CuII2L55Bu4]4+ in the catalytic oxidations of several biogenic catechols (L-/D-dopa, L-/D-DopaOMe, and L-/D-norepinephrine) and thioanisole are reported. The best discriminating properties are displayed towards the DopaOMe derivatives, for which the oxidation rate of the L enantiomer is approximately one order of magnitude larger than that of the opposite D isomer. A dinuclear copper(II) complex derived from a chiral hexadentate nitrogen ligand is reported as a new catalyst for asymmetric oxidations. For biogenic catechols as model substrates, the best enantioselectivity is obtained in the oxidation of the methyl esters of L-/D-Dopa, for which 70%ee is obtained in favor of the L enantiomer.
Synthesis, Characterization, and Stereoselective Oxidations of the Dinuclear Copper(II) Complex Derived from a Chiral Diamino-m-xylenetetra(benzimidazole) Ligand / M.L. Perrone, E. Lo Presti, S. Dell'Acqua, E. Monzani, L. Santagostini, L. Casella. - In: EUROPEAN JOURNAL OF INORGANIC CHEMISTRY. - ISSN 1434-1948. - 2015:21(2015 Jul), pp. 3493-3500.
|Titolo:||Synthesis, Characterization, and Stereoselective Oxidations of the Dinuclear Copper(II) Complex Derived from a Chiral Diamino-m-xylenetetra(benzimidazole) Ligand|
SANTAGOSTINI, LAURA (Penultimo)
|Parole Chiave:||Asymmetric catalysis; Bioinorganic chemistry; Copper; Ligand design; Oxidation; Inorganic Chemistry|
|Settore Scientifico Disciplinare:||Settore CHIM/03 - Chimica Generale e Inorganica|
|Data di pubblicazione:||lug-2015|
|Digital Object Identifier (DOI):||http://dx.doi.org/10.1002/ejic.201500046|
|Appare nelle tipologie:||01 - Articolo su periodico|
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