The Instability of Ni{N(SiMe3)2}2: A Fifty Year Old Transition Metal Silylamide Mystery

• Published in: Angewandte Chemie International Edition Vol. 54; no. 44; pp. 12914 - 12917
• Main Authors: Faust, Michelle, Bryan, Aimee M., Mansikkamäki, Akseli, Vasko, Petra, Olmstead, Marilyn M., Tuononen, Heikki M., Grandjean, Fernande, Long, Gary J., Power, Philip P.
• Format: Journal Article
• Language: English
• Published: Weinheim WILEY-VCH Verlag 26.10.2015; WILEY‐VCH Verlag; Wiley Subscription Services, Inc
• Edition: International ed. in English
• Subjects: Computer applications; dispersion effects; magnetism; Nickel; Nickel chloride; Pyridines; silylamide; steric effects; Transition metals; silylamide; steric effects; magnetism; dispersion effects; nickel
• ISSN: 1433-7851; 1521-3773
• DOI: 10.1002/anie.201505518

The characterization of the unstable NiII bis(silylamide) Ni{N(SiMe3)2}2 (1), its THF complex Ni{N(SiMe3)2}2(THF) (2), and the stable bis(pyridine) derivative trans‐Ni{N(SiMe3)2}2(py)2 (3), is described. Both 1 and 2 decompose at ca. 25 °C to a tetrameric NiI species, [Ni{N(SiMe3)2}]4 (4), also obtainable from LiN(SiMe3)2 and NiCl2(DME). Experimental and computational data indicate that the instability of 1 is likely due to ease of reduction of NiII to NiI and the stabilization of 4 through dispersion forces. The singular instability of Ni{N(SiMe3)2}2, one of the original transition metal silylamides of Bürger and Wannagat, was re‐investigated: it likely results from its tendency to undergo autoreduction into the dispersion force stabilized NiI tetramer [Ni{N(SiMe3)2}]4 (see picture; Si light blue, N dark blue, Ni green), the first neutral homoleptic NiI amide.