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Dioxygenase‐Like Reactivity of an Isolable Superoxo–Nickel(II) Complex
Author(s) -
Company Anna,
Yao Shenglai,
Ray Kallol,
Driess Matthias
Publication year - 2010
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201001138
Subject(s) - reactivity (psychology) , chemistry , nickel , oxidizing agent , catalysis , ligand (biochemistry) , isopropyl , aryl , hydrogen atom abstraction , nucleophile , intramolecular force , medicinal chemistry , reductive elimination , photochemistry , stereochemistry , hydrogen , organic chemistry , alkyl , medicine , biochemistry , alternative medicine , receptor , pathology
Although O 2 activation by metals such as iron and copper has been a matter of intensive research in the last decades, this type of chemistry for nickel systems is still in its infancy. Moreover, studies regarding the oxidizing ability of the resulting “Ni n –O 2 ” species towards exogenous substrates are scarce. In this work, we report on the reactivity of an isolable and thermally stable mononuclear superoxo–nickel compound [Ni II (β‐diketiminato)(O 2 )] ( 1 ) towards different types of organic substrates. In addition, we have been able to prove that the β‐diketiminato ligand can undergo partial intramolecular oxidation due to close proximity between the isopropyl groups of the β‐diketiminato‐aryl and the superoxo subunits. Compound 1 performs hydrogen‐atom abstraction from O‐H and N‐H groups and most importantly it shows an unprecedented dioxygenase‐like reactivity in the oxidation of 2,4,6‐tri‐ tert ‐butylphenol. The latter reaction most likely occurs through the mediation of a putative [Ni III ‐oxo] intermediate, affording an unprecedented oxidation product of the phenol that incorporates two oxygen atoms from a single O 2 subunit. Results presented herein provide evidence of the striking oxidizing ability of dioxygen–nickel species and further support the viability to use such systems as oxidation catalysts analogous to its heavy metal congener, palladium.