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Preparation and Characterisation of a Bis‐μ‐Hydroxo‐Ni III 2 Complex
Author(s) -
Spedalotto Giuseppe,
Gericke Robert,
Lovisari Marta,
Farquhar Erik R.,
Twamley Brendan,
McDonald Aidan R.
Publication year - 2019
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.201902812
Subject(s) - hydroxide , bimetallic strip , chemistry , electron paramagnetic resonance , oxidizing agent , reactivity (psychology) , inorganic chemistry , ligand (biochemistry) , density functional theory , absorption spectroscopy , nuclear chemistry , crystallography , metal , organic chemistry , computational chemistry , nuclear magnetic resonance , receptor , pathology , quantum mechanics , medicine , biochemistry , physics , alternative medicine
Abstract Hydroxide‐bridged high‐valent oxidants have been implicated as the active oxidants in methane monooxygenases and other oxidases that employ bimetallic clusters in their active site. To understand the properties of such species, bis‐μ‐hydroxo‐Ni II 2 complex ( 1 ) supported by a new dicarboxamidate ligand ( N , N ′‐bis(2,6‐dimethyl‐phenyl)‐2,2‐dimethylmalonamide) was prepared. Complex 1 contained a diamond core made up of two Ni II ions and two bridging hydroxide ligands. Titration of the 1 e − oxidant (NH 4 ) 2 [Ce IV (NO 3 ) 6 ] with 1 at −45 °C showed the formation of the high‐valent species 2 and 3 , containing Ni II Ni III and Ni III 2 diamond cores, respectively, maintaining the bis‐μ‐hydroxide core. Both complexes were characterised using electron paramagnetic resonance, X‐ray absorption, and electronic absorption spectroscopies. Density functional theory computations supported the spectroscopic assignments. Oxidation reactivity studies showed that bis‐μ‐hydroxide‐Ni III 2 3 was capable of oxidizing substrates at −45 °C at rates greater than that of the most reactive bis‐μ‐oxo‐Ni III complexes reported to date.