| الوصف: |
We report herein the synthesis, spectroscopic and structural characterization of a series of NHC-stabilized copper aryl complexes (NHC = N-heterocyclic carbene) of the type [Cu(NHC)(Ar)] 1–5, 7–22 with various aryl ligands (4-Me-C6H4, 4-MeO-C6H4, 2,4,6-Me3C6H2, C6F5, 4-CF3-C6H4, (3,5-(CF3)2C6H3), 2,3,5,6-Me4-C6H, 2,6-iPr2-C6H3, C6Me5) and NHCs (IiPr, ItBu, IMes, IPr). Three different synthetic routes were used to obtain these complexes: (i) reaction of a copper(I) aryl complex with a free NHC; (ii) reaction of an NHC-stabilized copper(I) chloride with a Grignard reagent, which is one important step in Kumada-Tamao-Corriu type cross-coupling reactions; and (iii) reaction of an NHC-stabilized copper(I) alkoxide with an organoboronic ester, which represents an important step in Suzuki-Miyaura type cross-coupling reactions. The latter process was investigated in detail by VT-NMR experiments using [Cu(IPr)(OtBu)] and 4-CF3-C6H4Bpin as an example, revealing the formation of an adduct (A) as a reaction intermediate. Furthermore, the reactivity of the [Cu(NHC)(Ar)] complexes towards aryl halides was investigated. |
