Related Experiment Video
Updated: Mar 26, 2026

Palladium N-Heterocyclic Carbene Complexes: Synthesis from Benzimidazolium Salts and Catalytic Activity in Carbon-carbon Bond-forming Reactions
Published on: July 30, 2017
Half-sandwich nickel complexes with ring-expanded NHC ligands - synthesis, structure and catalytic activity in
Ł Banach1, P A Guńka, W Buchowicz
1Faculty of Chemistry, Warsaw University of Technology, Noakowskiego 3, 00-664 Warsaw, Poland. wbuch@ch.pw.edu.pl.
Abstract:
The general synthesis of [Ni(Cp)(X)(NHC)] complexes from a nickel halide, CpLi, and a carbene solution is reported. This procedure yields unprecedented complexes with ring-expanded NHC ligands (RE-NHC) of six- (1a, 1b), seven- (1c), and eight-membered (1d) heterocycles. The NMR spectra of 1a-1d are consistent with the hindered rotation of Ni-Ccarbene and N-CMes bonds, while X-ray analyses of 1b, 1c, and 1d reveal a pronounced trans influence of the RE-NHC ligands. Complexes 1a-1e are efficient pre-catalysts in Kumada-Tamao-Corriu coupling with the maximum efficiency observed for complexes bearing the six-membered NHC.
More Related Videos
Related Concept Videos
Catalysis
Diazonium Group Substitution with Halogens and Cyanide: Sandmeyer and Schiemann Reactions
Heterogeneous Catalysis
Reduction of Alkenes: Asymmetric Catalytic Hydrogenation
The metal catalyst used can be either heterogeneous or homogeneous. When hydrogenation of an alkene generates a chiral center, a pair of enantiomeric products is expected to form. However, an enantiomeric excess of one of the products can be facilitated using an enantioselective reaction or an...
[4+2] Cycloaddition of Conjugated Dienes: Diels–Alder Reaction
Thermal Electrocyclic Reactions: Stereochemistry
Selection Rules: Thermal Activation
Conjugated systems containing an even number of π-electron pairs undergo a conrotatory ring closure. For example, thermal electrocyclization of (2E,4E)-2,4-hexadiene, a conjugated diene containing two π-electron pairs, gives trans-3,4-dimethylcyclobutene.

