A planar chelating bitriazole N-heterocyclic carbene ligand and its rhodium(iii) and dirhodium(ii) complexes

Abstract

The new ligand bitriazole-2-ylidene (bitz) reliably chelates to Rh under very mild conditions, providing an NHC analogue of 2,2'-dipyridyl ligand.

Recent developments in homobimetallic reagents and catalysts for organic synthesis

“…This complex was found to be catalytically active in the transfer hydrogenation of acetophenone and benzophenone with i-PrOH/t-BuOK. The reactivity is similar to that of the monorhodium complex 87 [96].…”

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

“…[121] In a subsequent paper, [122] the same group expanded the linker and the resulting Ir complex was applied to the transfer hydrogenation of aldehydes (a more challenging reaction due to possible decarbonylation and aldol side reactions in the presence of base) at low catalyst loading (0.1 mol-%). Finally, other chelating bis(carbene) complexes were tested in transfer hydrogenation, [123] notably a bitriazole NHC, [124] however activities were low. An intriguing tripodal NHC complex of Rh III (78, Scheme 10) was described by Peris, displaying good activities (loadings down to 0.001 mol-%) for a range of substrates including imines.…”

Mono‐, Bi‐ and Tridentate N‐Heterocyclic Carbene Ligands for the Preparation of Transition‐Metal‐Based Homogeneous Catalysts

“…[31] Scheme 5. cal versatility and was recently coordinated to Rh, Ru and Pd. [32,33] For the coordination of 16 to Rh, different products were obtained, depending on the conditions employed (17, 18 and 19, Scheme 8). [32,33] Interestingly, the reaction of 16 with [Rh(OAc)(CO) 2 ] 2 yielded the dirhodium(II) species 20 (Scheme 9).…”