Synthesis, Characterization and Reactivity of N-Heterocyclic Carbene Gold(III) Complexes

• DOI: 10.1021/om060887t
• Publication Date: 2007-02-07T12:15:34Z
• Authors: Pierre de Frémont; Rohit Singh; Edwin D. Stevens; Jeffrey L. Petersen; Steven P. Nolan
• Keywords: IMes; Reactivity; Oxidative addition

A series of (NHC)AuICl (1, NHC = N,N'-bis(2,6-diisopropylphenyl)imidazol-2-ylidene (IPr); 2, N,N'-bis(2,4,6-trimethylphenyl)imidazol-2-ylidene (IMes); 3, N,N'-bis(2,6-diisopropylphenyl)imidazolin-2-ylidene (SIPr); 4, N,N'-bis(2,4,6-trimethylphenyl)imidazolin-2-ylidene (SIMes); 5, N,N'-dicyclohexylimidazol-2-ylidene (ICy); 6, N,N'-diadamantylimidazol-2-ylidene (IAd); 7, N,N'-di-tert-butylimidazol-2-ylidene (ItBu)) complexes were reacted with LiBr to generate [(IPr)AuBr] (8), [(IMes)AuBr] (9), [(SIPr)AuBr] (10), [(SIMes)AuBr] (11), [(ICy)AuBr] (12), [(IAd)AuBr] (13), and [(ItBu)AuBr] (14). These (NHC)AuIBr undergo oxidative addition elemental bromine, leading the new Au(III) [(IPr)AuBr3] (15), [(IMes)AuBr3] (16), [(SIPr)AuBr3] (17), [(SIMes)AuBr3] (18), [(ICy)AuBr3] (19), [(IAd)AuBr3] (20), [(ItBu)AuBr3] (21). Complete characterization by NMR spectroscopy single-crystal X-ray diffraction performed in order discern structural differences between organogold(I/III) congeners. preliminary study examining activity (NHC)AuIII species on water alkynes is also presented.