Journal
CHEMISTRY-A EUROPEAN JOURNAL
Volume 22, Issue 35, Pages 12340-12346Publisher
WILEY-V C H VERLAG GMBH
DOI: 10.1002/chem.201600833
Keywords
amides; hydrogen bonds; reactive intermediates; solvent effects; X-ray diffraction
Categories
Funding
- DNRF by the Centre of Materials Crystallography [DNRF93]
Ask authors/readers for more resources
Alkali metal 1,1,1,3,3,3-hexamethyldisilazide (MHMDSs) are one of the most utilised weakly nucleophilic BrOnsted bases in synthetic chemistry and especially in natural product synthesis. Like lithium organics, they aggregate depending on the employed donor solvents. Thus, they show different reactivity and selectivity as a function of their aggregation and solvation state. To date, monomeric LiHMDS with monodentate donor bases was only characterised in solution. Since the first preparation of LiHMDS in 1959 by Wannagat and Niederprum, all efforts to crystallise monomeric LiHMDS in the absence of chelating ligands failed. Herein, we present ammonia adducts of LiHMDS, NaHMDS, KHMDS, RbHMDS and CsHMDS with unprecedented aggregation motifs: 1)The hitherto missing monomeric key compound in the LiHMDS aggregation architectures. Monomeric crystal structures of trisolvated LiHMDS (1) and NaHMDS (2), showing unique intermolecular hydrogen bonds, 2)the unprecedented tetrasolvated KHMDS (3) and RbHMDS (4) dimers and 3)the disolvated CsHMDS (5) dimer with very close intermolecular Si-CH3Cs s-block agostic interactions have been prepared and characterised by single-crystal X-ray structure analysis.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available