Two series of different Cu(I)-complexes of “click” derived mesoionic carbenes are reported. Halide complexes of the type (MIC)CuI (with MIC = 1,4-(2,6-diisopropyl)-phenyl-3-methyl-1,2,3-triazol-5-ylidene (for
1b), 1-benzyl-3-methyl-4-phenyl-1,2,3-triazol-5-ylidene (for
1c)) and cationic complexes of the general formula [Cu(MIC)
2]X (with MIC =1,4-dimesityl-3-methyl-1,2,3-triazol-5-ylidene, X
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Two series of different Cu(I)-complexes of “click” derived mesoionic carbenes are reported. Halide complexes of the type (MIC)CuI (with MIC = 1,4-(2,6-diisopropyl)-phenyl-3-methyl-1,2,3-triazol-5-ylidene (for
1b), 1-benzyl-3-methyl-4-phenyl-1,2,3-triazol-5-ylidene (for
1c)) and cationic complexes of the general formula [Cu(MIC)
2]X (with MIC =1,4-dimesityl-3-methyl-1,2,3-triazol-5-ylidene, X = CuI
2− (for
2á), 1,4-dimesityl-3-methyl-1,2,3-triazol-5-ylidene, X = BF
4− (for
2a), 1,4-(2,6-diisopropyl)phenyl-3-methyl-1,2,3-triazol-5-ylidene, X = BF
4− (for
2b), 1-benzyl-3-methyl-4-phenyl-1,2,3-triazol-5-ylidene, X = BF
4− (for
2c)) have been prepared from CuI or [Cu(CH
3CN)
4](BF
4) and the corresponding ligands, respectively. All complexes were characterized by elemental analysis and standard spectroscopic methods. Complexes
2á and
1b were studied by single-crystal X-ray diffraction analysis. Structural analysis revealed
2á to adopt a cationic form as [Cu(MIC)
2](CuI
2) and comparison of the NMR spectra of
2á and
2a confirmed this conformation in solution. In contrast, after crystallization complex
1b was found to adopt the desired neutral form. All complexes were tested for the reduction of cyclohexanone under hydrosilylation condition at elevated temperatures. These complexes were found to be efficient catalysts for this reaction.
2c was also found to catalyze this reaction at room temperature. Mechanistic studies have been carried out as well.
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