Mononuclear Rhodium(I) Complexes with Chelating N‐Heterocyclic Carbene Ligands − Catalytic Activity for Intramolecular Hydroamination

Cationic and Neutral Rhodium(I) Oxazolinylcarbene Complexes

“…The rhodiumϪcarbene distance [RhϪC(2) ϭ 1.950(4) Å ] and the rhodiumϪnitrogen distance [RhϪN(3) ϭ 2.143(3) Å ]) are within the expected range. [13] It is interesting to compare the CϪRhϪN bite angles of the chelating oxazolinylcarbene ligand in the molecular structures of compounds 3Ϫ7. The values found for the five-coordinate complexes 3 and 4 are 77.47(9)°and 77.49(8)°, respectively, while the corresponding data of the square-planar cations 5 and 6 are 78.7(2)°and 78.2(2)°, respectively.…”

“…Signals characteristic of N-heterocyclic carbene carbon nuclei [4,5] at δ ϭ 177.2 ppm (J Rh,C ϭ 53 Hz) and at δ ϭ 183.6 ppm (J Rh,C ϭ 55 Hz) were observed for complexes 3 and 4, respectively Furthermore, a significant coordination shift of the C(ϭN)O 13 C NMR resonances in both cases (3: δ ϭ 158.8 ppm; 4: δ ϭ 155.6 ppm) in comparison with the ligand precursor 2 (δ ϭ 148.8 ppm) indicates the coordination of the oxazoline ring. The latter is also supported by the oxazoline ν(CϭN) vibrational band which is shifted to lower wavenumbers (3: ).…”

Transition Metal-Catalyzed Reactions Using N-Heterocyclic Carbene Ligands (Besides Pd- and Ru-Catalyzed Reactions)

“…Turner and coworkers have found that Rh catalysts derived from the NHC chelating ligands are capable of catalyzing intramolecular hydroaminations (Eq. 38) [83,84]. Using 1.5 mol % of complex 39, 76 and 85% conversions were obtained after 16 h for the BPh 4 and PF 6 analogs, respectively [83].…”

Donor‐Functionalised N‐Heterocyclic Carbene Complexes of Group 9 and 10 Metals in Catalysis: Trends and Directions

“…[131,[186][187][188] These reactions produce interesting cyclic imines or lactones in an atom economical process. Amongst other cationic Rh I and Ir I complexes, triScheme 24.…”