NHC-amide donor ligands in rhodium complexes: Syntheses and characterisation

Polymer‐Supported Palladium(II) Carbene Complexes: Catalytic Activity, Recyclability, and Selectivity in C−H Acetoxylation of Arenes

“…13 CNMR spectra showedt he characteristic carbene signals at 180.7 and 180.9 ppm for 2a and 2b,r espectively. [46][47][48][49][50] The use of silver intermediates precluded any radical polymerization of the vinyl moiety at an earlier stage;s ome other protocols use harsh reactionc onditions under which such unwanteds ide reactions could occur. [51] Transmetallation with PdCl 2 (PhCN) 2 gave NHC-Pd II dimers 3a and 3b (Ref.…”

“…Direct metallation using literature procedures afforded [Ag(bmim) 2 ] 2 [Ag 2 Cl 4 ] 2 a and Ag[bvbim]Cl complex 2 b in good yield (Figure ). 13 C NMR spectra showed the characteristic carbene signals at 180.7 and 180.9 ppm for 2 a and 2 b , respectively . The use of silver intermediates precluded any radical polymerization of the vinyl moiety at an earlier stage; some other protocols use harsh reaction conditions under which such unwanted side reactions could occur .…”

Arylamidoethyl-Functionalized Imidazolium Salts: Precursors for Dianionic [C,N,C]2– Carbene Ligands at a Platinum Center

“…The product was obtained as an orange-yellow solid in 71% yield. 1 H NMR (DMSO-d 6 , 600 MHz): δ 8.67 (t, J = 1.8 Hz, 1 H, NH), 8.37 (t, J = 1.9 Hz, 1 H, H2), 8.17 (ddd, J = 8.6, 2.2, 0.9 Hz, 1 H, H4), 7 [Pt( CM L 2 )(HL 2 )]. This was prepared as described above using PtCl 2 (0.123 g, 0.460 mmol), K 2 CO 3 (0.319 g, 2.31 mmol), and H 2 L 2 (0.286 g, 0.92 mmol).…”

“…7−10 In the palladium complexes, the NHC acts as a neutral C-donor ligand, while in the rhodium compounds, both a C-donor mode and a bidentate [C,N] − coordination mode (upon deprotonation of the amide) have been observed. 7,9,10 In the rare-earth complexes, the carbene acts as a monoanionic, tridentate [C,N,O] − ligand, forming one six-and one five-membered chelate ring at the metal. 8 The structurally related imidazolium salts containing ArCH pyridyl) react with Ni(II) or Pd(II) salts in the presence of a base to give bis(carbene) complexes in which the doubly deprotonated imidazolium salt acts as a [C,N] − ligand.…”

“…Mesityl imidazolium salts containing different arylamidoethyl substituents ArC­(O)­NH­(CH 2 ) 2 have been previously reported as precursors toward palladium­(II)-, rhodium­(I)-, and lanthanide­(III)-NHC complexes. − In the palladium complexes, the NHC acts as a neutral C -donor ligand, while in the rhodium compounds, both a C -donor mode and a bidentate [ C , N ] − coordination mode (upon deprotonation of the amide) have been observed. ,, In the rare-earth complexes, the carbene acts as a monoanionic, tridentate [ C , N , O ] − ligand, forming one six- and one five-membered chelate ring at the metal . The structurally related imidazolium salts containing ArCH 2 NHC­(O)­CH 2 substituents (Ar = Ph, 2-pyridyl) react with Ni­(II) or Pd­(II) salts in the presence of a base to give bis­(carbene) complexes in which the doubly deprotonated imidazolium salt acts as a [ C,N ] − ligand. − There appear to be no examples containing platinum with this ligand system.…”