Frustrated N-heterocyclic carbene-silylium ion Lewis pairs

The reaction of the N-heterocyclic carbene 1,3-di-tert-butyl-4,5-dimethylimidazolin-2-ylidene () with trimethylsilyl iodide, triflate and triflimidate [Me3SiX, X = I, CF3SO3 (OTf), (CF3SO2)2N (NTf2)] by mixing the neat, liquid starting materials afforded the corresponding 2-(trimethylsilyl)imidazoli...

Full description

Saved in:
Bibliographic Details
Published in:Dalton transactions : an international journal of inorganic chemistry 2015-05, Vol.44 (20), p.9400-9408
Main Authors: Silva Valverde, Miguel F, Theuergarten, Eileen, Bannenberg, Thomas, Freytag, Matthias, Jones, Peter G, Tamm, Matthias
Format: Article
Language:English
Subjects:
Bonding
Carbon dioxide
Crystal structure
Diffraction
Iodides
Liquids
Mathematical analysis
NMR spectroscopy
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:The reaction of the N-heterocyclic carbene 1,3-di-tert-butyl-4,5-dimethylimidazolin-2-ylidene () with trimethylsilyl iodide, triflate and triflimidate [Me3SiX, X = I, CF3SO3 (OTf), (CF3SO2)2N (NTf2)] by mixing the neat, liquid starting materials afforded the corresponding 2-(trimethylsilyl)imidazolium salts [()SiMe3]X as highly reactive, white crystalline solids. Only the triflimidate (X = NTf2) proved to be stable in solution and could be characterized by means of NMR spectroscopy (in C6D5Br) and X-ray diffraction analysis, whereas dissociation into free and Me3SiOTf was observed for the triflate system, in agreement with the trend derived by DFT calculations; the iodide was too insoluble for characterization. The compounds [()SiMe3]X showed the reactivity expected for frustrated carbene-silylium pairs, and treatment with carbon dioxide, tert-butyl isocyanate and diphenylbutadiyne gave the 1,2-addition products [()CO2SiMe3]X (X = I, OTf, NTf2), [()C(NtBu)OSiMe3]OTf and [()C(Ph)C(SiMe3)CCPh]OTf, respectively. Upon reaction with [AuCl(PPh3)], metal-chloride bond activation was observed, with formation of the cationic gold(i) complexes [()Au(PPh3)]X (X = OTf, NTf2).
ISSN:1477-9226
1477-9234
DOI:10.1039/c5dt01362c