A Novel Class of Ruthenium Catalysts for Olefin Metathesis

N‐Heterocyclic Carbene Functionalized Iridium Phosphinidene Complex [Cp*(NHC)IrPMes*]: Comparison of Phosphinidene, Imido, and Carbene Complexes

“…Interestingly, the difference between the Ir C and Ir À C(NHC) distances of 0.08 ä in 6 is much less pronounced compared with NHC ligated Ru alkylidene complexes (0.23 ± 0.30 ä). [2,6] This suggests the NHC ligands to be tighter bound in the Ir complexes than in the Ru analogues.…”

“…[1,2] Neutral imidazol-2-ylidenes, which are now readily available from established synthetic procedures, [1,3] are thermally stable ligands that exhibit strong s-donor and negligible p-acceptor capabilities.…”

“…[4,6,7] Phosphine substitution in the established Rubased Grubbs catalysts [(PR 3 ) 2 Cl 2 RuCHR'] by imidazol-2-ylidenes, has already provided new catalytic systems with superior activities in olefin metathesis. [2,6] Interestingly, these Ru complexes represent the only known examples of a new class of compounds that contain both an alkylidene moiety as well as an N-heterocyclic carbene ligand. [2] Similar complexes of other transition metals have not yet been reported, and neither have N-heterocyclic carbene complexes that bear reactive metal ± ligand multiple bonds other than an alkylidene, such as imido (MNR) and phosphinidene (MPR) moieties.…”

Synthesis by self-assembly and structural characterization of a new co-crystal system {[Cu(NO3)2(H2O)2]L1(NO3)2} (L1 = 1,1′-dibenzyl-3,3′-butyl-diimidazolium-2,2′-diylidene) from copper nitrate and a carbene precursor

“…Recently carbene chemistry has become an active field of research towards applications in catalysis [1][2][3][4][5], NLO [6][7][8][9][10] and liquid crystals [11][12][13][14][15]. For liquid crystal applications, the imidazole rings in particular, provide an effective way to introduce large alkyl chains within the ligand and effectively tune the final properties of such compounds [16][17][18].…”

NHC Ruthenium Complexes as Second Generation Grubbs Catalysts

“…1,2 On the other hand, the achievements in the evolution of homogeneous catalysts for olefin metathesis have turned this reaction into a common C-C coupling process 3 with various possibilities including ring-opening metathesis polymerization (ROMP), ring-closing metathesis (RCM), acyclic diene metathesis polymerization (ADMET), ring-opening metathesis (ROM), and cross-metathesis (CM or XMET). Herrmann et al 4 were the first to synthesize a modified Grubbs catalyst that included N-heterocyclic carbene ligands. The bis(NHC)-substituted derivatives 2 showed a minor improvement in terms of catalytic activity compared to conventional Grubbs catalyst 1.…”