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Published on: November 11, 2013
Towards Hexagonal Planar Nickel: A Dispersion-Stabilised Tri-Lithium Nickelate
Andryj M Borys1, Lorraine A Malaspina1, Simon Grabowsky1
1Departement für Chemie, Biochemie und Pharmazie, Universität Bern, Freiestrasse 3, 3012, Bern, Switzerland.
Abstract:
Advancing the understanding of lithum nickelate complexes, here we report a family of homoleptic organonickelate complexes obtained by reacting Ni(COD)2 and lithium aryl-acetylides in the presence of the bidentate donor TMEDA. These compounds represent rare examples of low-valent transition-metals supported solely by organolithium ligands. Whilst the solid-state structures indicate a hexagonal planar geometry around Ni0 with Ni-Li bonds, bonding analysis via QTAIM, NCI, NBO and ELI methods reveals that the Ni-Li interactions are repulsive in nature, characterising these complexes as tri-coordinated. London dispersion forces between TMEDA and the organic substituents on nickel are found to play a crucial role in the stabilisation and thus isolation of these complexes. Preliminary reactivity studies demonstrate that the homoleptic lithium nickelates undergo stoichiometric cross-coupling with PhI to give dinickel clusters containing both anionic acetylide and neutral alkyne ligands.
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