Issue 28, 2017

Coordination behavior of bidentate bis(carbenes) at alkali metal bis(trimethylsilyl)amides

Abstract

Lithiation of HN(SiMe3)2 in hexane and crystallization in the presence of 2,2,5,5-tetramethyltetrahydrofuran (Me4THF) allows the isolation of crystalline tetrameric [LiN(SiMe3)2]4 (1) with an average Li–N distance of 208.9 pm. Deprotonation of a methylene-bridged bis(imidazolium) diiodide with NaN(SiMe3)2 in tetrahydrofuran (THF) yields 1,1′-diisopropyl-3,3′-methylene-diimidazole-2,2′-diylidene (H2C(NHCiPr)2) and layering of this orange reaction mixture with pentane yield [{H2C(NHCiPr)2}{(thf)NaI}2] (2). The reaction of this bis(imidazolium) diiodide with excess of KN(SiMe3)2 in THF leads to the formation of [{H2C(NHCiPr)2}KN(SiMe3)2]2 (3). Due to the fact that 2 and 3 are polymeric in the crystalline state, the bulkier 1,1′-bis(2,6-diisopropylphenyl)-3,3′-methylene-diimidazole-2,2′-diylidene (H2C(NHCDipp)2) has been used. Thus, addition of H2C(NHCDipp)2 with the bulky 2,6-diisopropylphenyl (Dipp) groups to AN(SiMe3)2 (A = Li, Na, K) in toluene yields mononuclear [{H2C(NHCDipp)2}LiN(SiMe3)2] (4) and dinuclear [{H2C(NHCDipp)2}AN(SiMe3)2]2 for sodium (5) and potassium (6). The rather short alkali metal–carbon bonds lie in the range of alkylmetal derivatives.

Graphical abstract: Coordination behavior of bidentate bis(carbenes) at alkali metal bis(trimethylsilyl)amides

Supplementary files

Article information

Article type
Paper
Submitted
27 Apr 2017
Accepted
21 Jun 2017
First published
22 Jun 2017

Dalton Trans., 2017,46, 9058-9067

Coordination behavior of bidentate bis(carbenes) at alkali metal bis(trimethylsilyl)amides

A. Koch, H. Görls, S. Krieck and M. Westerhausen, Dalton Trans., 2017, 46, 9058 DOI: 10.1039/C7DT01538K

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