The advantages of N-heterocyclic carbene’s as ..
The ability to tune the emission is attributed to electronic transitions of mixed ligand-to-metal-metal-charge-transfer (IPr → AuM2) and interligand (IPr → E) phosphorescence character, as revealed by time-dependent density functional theory computations.N-heterocyclic carbenes (NHCs) have been applied as ancillary ligands in the synthesis of luminescent gold(I) chalcogenide clusters and this approach allows for unprecedented selectivity over the metal and chalcogen ions present within a stable octanuclear framework.
N-Heterocyclic Carbenes in Catalytic Organic Synthesis
Nickel carbene complexes are potential cost-saving alternatives to Pd-catalysts. However, only few nickel carbene complexes have been reported so far due to the lack of synthetic procedures for their preparation. We have developed a one-pot approach for the synthesis of the first benzimidazolin-2-ylidene complexes of nickel(II) using ammonium salts as ionic liquids. With this methodology, a library of nickel(II) NHC complexes of different steric demands have been synthesized and structurally characterized. The dependence of sterically demanding substituents on the catalytic activities of these complexes is currently under investigation. Some of the complexes exhibit rare preagostic C-H xxx Ni interactions.
Hello Halo! An unprecedented highly enantioselective, Brønsted base catalyzed [4+2] cycloaddition of α-haloaldehydes and electron-deficient cyclic enones has been developed. A series of fused bicyclic dihydropyrans featuring a halogenated quaternary stereocenter was synthesized in excellent yields with up to >99 % ee under mild reaction conditions. These products were further transformed into spirocyclopropanes having two vicinal all-carbon quaternary centers.
N-Heterocyclic Carbenes (RSC Publishing)
New chiral C2 symmetric N-heterocyclic carbene (NHC) ligands with a binaphthyl backbone have been synthesized. X-ray crystallographic analysis of the new NHC-AuCl complex revealed that the phenyl groups of the binaphthyl backbone sterically regulated the direction of the nitrogen substituents of the imidazolylidene which would induce enantioselectivity in reactions. The new cationic NHC-Au(I) complexes efficiently catalyzed the cyclization of a 1,6-ene-yne and the intermediate of the cyclization was trapped by MeOH to afford the final product in high yields with up to 44% ee.
N-Heterocyclic Carbenes - Yumpu
Mixed dicarboxylato-bis(carbene) complexes of palladium(II) belong to an interesting novel class of complexes, which are scarcely investigated so far. We have shown that mono- and dicarbenes can stabilize the Pd-carboxylato moiety efficiently and therefore prevent reductive decomposition and auto-ionization processes - two important side-reactions that lead to catalysts deactivation of phosphine-carboxylato complexes. The preferably cis-configured complexes are highly active in the Mizoroki-Heck reaction.
N-heterocyclic carbenes - Revolvy
Giovanna Bosica is a researcher at the Department of Chemical Sciences of the University of Camerino. She received her Laurea in chemistry in 1993 from the University of Camerino and, four years later, from the same institution her doctoral degree in chemical sciences, working under the supervision of Prof. R. Ballini. She spent a research period in the laboratories of Prof. B. Zwanenburg (University of Nijmegen, The Netherlands, 1995). Her research interests concern the use of nitro compounds in new synthetic methodologies, functional groups interconversion, synthesis of biologically active natural products, and green chemistry.
Nolan "N-Heterocyclic Carbenes in Synthesis ..
Roberto Ballini received an S.B. degree in chemistry from the University of Camerino, Italy. After an experience in the petrochemical industry (ENI-ANIC, Ravenna), he began his academic career in 1975 at the University of Camerino as a Research Fellow. He became Assistant Professor in 1978, was promoted to Associate Professor of Organic Chemistry, and then to full Professor (organic chemistry) in 2000. His recent research interests include the chemistry of aliphatic nitrocompounds, the formation and cleavage of C−C bonds, the studies and application of heterogeneous catalysis, the synthesis of natural products, and the use of aqueous media in organic reactions.