Abnormal NHC ruthenium catalysts: mechanistic investigations of their preparation and steric influence on catalytic performance

Abstract

The bis-abnormal N-heterocyclic carbene (aNHC) ruthenium complexes [Ru(OAc)(aNHC-ethyl-PPh2)2]Br 1 and 3 are obtained from Ru(OAc)2(PPh3)2 with the ligands 1-(2-diphenylphosphino-ethyl)-3-aryl-imidazolium bromide (aryl = phenyl, di-iso-propylphenyl) LPh and LDipp in THF at...

Piano‐stool dinuclear ruthenium (II) complexes of pyrazine‐carboxylate/carboxamide ligands: Structural studies and catalytic transfer hydrogenation of ketones

“…However, complexes Ru1–Ru4 showed lower catalytic activities in relation to the dinuclear Ru (II) catalysts reported by Yu et al, 18,19 which display TOFs as high as 2.1 × 10 8 h. −1 Notably, a number of highly active mononuclear Ru (II) catalysts reported in literature show TOFs in the range of 10,000 to 550,000 h −1 (Table 3). For example, the Ru (II) complexes reported by Baratta 62 and Zhao 63 display TOFs of 550,000 h −1 (Table 3, entry 2) and 10,300 h −1 , respectively, in comparison with the TOF of 3000 h −1 achieved by the most active complex Ru4 , in this current study. On the other hand, catalysts Ru1–Ru4 displayed superior activities when compared to some previously reported mononuclear Ru (II) catalysts.…”

Synthesis, crystallographic structure, theoretical analysis, molecular docking studies, electronic properties and biological activity evaluation of ruthenium-complex bearing N-heterocyclic carbene ligand

“…Ru-NHC complexes have broad catalytic potential in a wide range of synthetic applications, including transfer hydrogenation of ketones, 29,30 metathesis reactions, 31 secondary oxidation of alcohols, 32 N-alkylation of amines, amides oxidation, and sulfonamides 33,34 and Oppenauer-type oxidations. 35,36 In previous studies, we introduced various substituents into ruthenium complexes, and synthesized four ruthenium complexes with MIC values ranging from 0.003 to 0.050 mg mL À1 against Staphylococcus aureus. Currently, we have developed two complexes based on benzimidazolium salts, aiming to develop new ruthenium complexes with higher antibacterial activity.…”

Cyclometalated C^N diphosphine ruthenium catalysts for Oppenauer-type oxidation/transfer hydrogenation reactions and cytotoxic activity

“…[27][28][29][30] Conversely, the Oppenauer-type oxidation of alcohols with acetone, which is the reverse reaction of TH, allows the preparation of carbonyl compounds from alcohols, avoiding the use of hazardous high-valent metal oxides. [31][32][33][34][35] These metal catalyzed equilibrium reactions, ruled by the redox potential of the carbonyl-alcohol couple, 36 are benign and straightforward processes that prevent the tedious workup steps of the original Al iso-propoxide procedures. [37][38][39][40][41] It is worth noting that more recently, ruthenium TH catalysts have also been investigated in cancer therapy aiming to disturb the NADH/NAD + and pyruvate/lactate redox homeostasis.…”

“…K): δ = 184.2 (s; COCH 3 ), 161.8 (dd,2 J CP = 18.2 Hz, 2 J CP = 8.4 Hz; C11-Ru), 148.0 (d; 3 J CP = 3.6 Hz; C10), 145.4 (s, ipso-C6), 141.1-125.9 (m; phenyl carbon atoms), 137.0 (s; C5), 123.4 (s; C3), 122.6 (s; C9), 119.5 (s; C8), 110.7 (s; C7), 106.4 (d, J CP = 3.1 Hz; C4), 30.3 (d,1 J CP = 25.9 Hz; PCH 2 ), 27.2 (d,1 J CP = 30.9 Hz; PCH 2 ), 25.7 (s; CH 2 ), 24.1 (s; OCOCH 3 ), 22.0 ppm (s; CH 2 ) 31. P{ 1 H}4 NMR (162.0 MHz, CD 2 Cl 2 , 298 K): δ = 58.0 (d, 2 J PP = 39.1 Hz), 53.4 ppm (d, 2 J PP = 39.1 Hz).…”