Tridentate, anionic tethered N-heterocyclic carbene of Pd(II) complexes

Binuclear meta‐xylyl‐linked Ag(I)‐N‐heterocyclic carbene complexes of N‐alkyl/aryl‐alkyl‐substituted bis‐benzimidazolium salts: synthesis, crystal structures and in vitro anticancer studies

“…Both bromide and hexafluorophosphate salts were characterized by NMR spectral method over the range δ 0–12. In the 1 H NMR spectra of the salts, a characteristic downfield resonance in the range δ 10.18–10.31 corresponding to the NCHN proton indicated the successful formation of benzimidazolium salts . Spectra also evidenced the presence of a set of peaks in the range δ 7.4–7.9 and 5.7–6.1, ascribed to the resonance of aromatic and benzyl protons, respectively.…”

A new C2-symmetric azolium compound for Cu-catalyzed asymmetric conjugate addition of R2Zn to cyclic enone

“…Treatment of 6 with Bu 2 Zn in DMA gave (S)-12 with a somewhat lower ee value (Run 2). Reaction of a cyclic enone consisting of a seven-membered ring such as 2-cyclohepten-1-one (13) increased the stereoselectivity (Runs 3e6). For example, cyclic enone 13 efficiently underwent 1,4-addition with Et 2 Zn in DMA to afford (S)-3-ethylcycloheptanone (14) in 96% yield and 85% ee (Run 4).…”

“…Note that the Pd(II) complex derived from a chiral b-amino alcohol catalyzes an asymmetric oxidative Heck-type reaction with excellent enantioselectivity. Encouraged by this success, we developed an efficient route to a huge variety of chiral NHC precursors, such as azolium salts and the tridentate, anionic tethered NHCePd(II) complexes [13]. Ligand precursors, such as azolium chlorides, have also been tested in the Cu-catalyzed asymmetric conjugate addition of dialkylzincs to cyclic enones.…”

Benzimidazole‐based silver(I)–N‐heterocyclic carbene complexes as anti‐bacterials: synthesis, crystal structures and nucleic acids interaction studies

“…[37] Finally, a sharp band at around 2237 cm À1 is assigned to ν(C ≡ N) of the nitrile functionality. [38] The 1 H NMR spectra of benzimidazolium salts 1-5 in DMSO-d 6 exhibit a characteristic NCHN proton resonance at ca 10.00-10.10 ppm, suggesting the successful formation of the desired salts. This is quite consistent with data for other benzimidazole-based NHC precursors.…”

“…This is quite consistent with data for other benzimidazole-based NHC precursors. [38][39][40] The 1 H NMR spectra of all compounds display signals for the terminal hydrogen atoms of the allyl group at ca 4.36 and 4.53 ppm with typical J HH coupling constants ( 3 J HH =10.2-11.0 Hz cis and 3 J HH =17.0-17.2 Hz trans). In addition, the resonances of aliphatic protons of the alkyl chain are consistent in the range ca 0.86-4.50 ppm, which is in agreement with similar structures found in the literature.…”