Selective Transformation of Nickel-Bound Formate to CO or C-C Coupling Products Triggered by Deprotonation and Steered by Alkali-Metal Ions.

Autor: Zimmermann P; Institut für Chemie, Humboldt-Universität zu Berlin, Brook-Taylor-Straße 2, 12489, Berlin, Germany., Ar D; Institut für Chemie, Humboldt-Universität zu Berlin, Brook-Taylor-Straße 2, 12489, Berlin, Germany., Rößler M; Institut für Chemie, Humboldt-Universität zu Berlin, Brook-Taylor-Straße 2, 12489, Berlin, Germany., Holze P; Institut für Chemie, Humboldt-Universität zu Berlin, Brook-Taylor-Straße 2, 12489, Berlin, Germany., Cula B; Institut für Chemie, Humboldt-Universität zu Berlin, Brook-Taylor-Straße 2, 12489, Berlin, Germany., Herwig C; Institut für Chemie, Humboldt-Universität zu Berlin, Brook-Taylor-Straße 2, 12489, Berlin, Germany., Limberg C; Institut für Chemie, Humboldt-Universität zu Berlin, Brook-Taylor-Straße 2, 12489, Berlin, Germany.
Jazyk: angličtina
Zdroj: Angewandte Chemie (International ed. in English) [Angew Chem Int Ed Engl] 2021 Feb 01; Vol. 60 (5), pp. 2312-2321. Date of Electronic Publication: 2020 Nov 30.
DOI: 10.1002/anie.202010180
Abstrakt: The complexes [L tBu Ni(OCO-κ 2 O,C)]M 3 [N(SiMe 3 ) 2 ] 2 (M=Li, Na, K), synthesized by deprotonation of a nickel formate complex [L tBu NiOOCH] with the corresponding amides M[N(SiMe 3 ) 2 ], feature a Ni II -CO 2 2- core surrounded by Lewis-acidic cations (M + ) and the influence of the latter on the behavior and reactivity was studied. The results point to a decrease of CO 2 activation within the series Li, Na, and K, which is also reflected in the reactivity with Me 3 SiOTf leading to the liberation of CO and formation of a Ni-OSiMe 3 complex. Furthermore, in case of K + , the {[K 3 [N(SiMe 3 ) 2 ] 2 } + shell around the Ni-CO 2 2- entity was shown to have a large impact on its stabilization and behavior. If the number of K[N(SiMe 3 ) 2 ] equivalents used in the reaction with [L tBu NiOOCH] is decreased from 3 to 0.5, the deprotonated part of the precursor enters a complex reaction sequence with formation of [L tBu Ni I (μ-OOCH)Ni I L tBu ]K and [L tBu Ni(C 2 O 4 )NiL tBu ]. The same reaction at higher concentrations additionally led to the formation of a unique hexanuclear Ni II complex containing both oxalate and mesoxalate ([O 2 C-CO 2 -CO 2 ] 4- ) ligands.
(© 2020 The Authors. Angewandte Chemie International Edition published by Wiley-VCH GmbH.)
Databáze: MEDLINE
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