Silver(i) N-Heterocyclic Carbenes

Silver(I) complexes of mono- and bidentate N-heterocyclic carbene ligands: Synthesis, crystal structures, and in vitro antibacterial and anticancer studies

“…Furthermore, spectra also evidenced the peaks in the range δ 17.9-18.7, 48.5-50.0 and δ 128.1-131.0 ppm, which are assignable to resonance of methyl, benzylic and aromatic carbon nuclei. These spectral assignments are in well accord with the similar reported compounds [14].…”

Platinum(ii) N-heterocyclic carbene complexes: coordination and cyclometallation.

“…Silver NHC salts were then prepared via the reaction of imidazolium salt with silver oxide in DCM. 5,6,8 …”

“…3 Relatively simple synthetic procedures leading to precursor imidazolium salts have been elucidated, 4 and many routes that allow the introduction of an NHC ligand to a metal centre have been developed. The reaction of imidazolium salts with silver oxide giving an NHC complex of silver, which serves as a useful trans-metallating reagent, has proved particularly popular, [5][6][7][8] and we use it in this paper. Other interesting methods include the utilisation of an electron-reservoir complex, together with air, to generate NHCs, 9 or the use of imidazolium-2-carboxylates which lose CO 2 to generate NHCs, 10 though, increasingly, direct reaction of the imidazolium salt with the metal has found favour.…”

Catalytic asymmetric boron–boron addition to unsaturated molecules

“…Despite using the chiral imidazolylidene ligand, we observed no asymmetric induction on the reaction products, presumably because the chiral center is far from the metal. Also, the lability of the AgeC carbene bond could favor some equilibrium between [(mentimid) 2 Ag] AgCl 2 and [(mentimid)AgCl] [28], and thus makes it difficult to establish what the real catalytic species is. Alternatively, using chiral diboranes such as bis(diethyl-D-tartrateglycolato)diboron and bis(diisopropyl-D-tartrateglycolato)diboron and bis((þ)-pinanediolato) diboron resulted in a totally inhibited diboration reaction, making bis(catecholato)diboron the specific diborating reagent for this reaction with [(mentimid) 2 Ag]AgCl 2 .…”