Related Experiment Video
Updated: Jul 15, 2025

Isolating Free Carbenes, their Mixed Dimers and Organic Radicals
Published on: April 19, 2019
Reactivity of free N-heterocyclic carbenes in dichloromethane
Magnus R Buchner1, Deniz F Bekiş1
1Anorganische Chemie, Nachwuchsgruppe Berylliumchemie, Fachbereich Chemie, Philipps-Universität Marburg, Hans-Meerwein-Straße 4, 35032 Marburg, Germany. magnus.buchner@chemie.uni-marburg.de.
Abstract:
The reactivity of free 1,3-diisopropyl-4,5-dimethylimidazol-2-ylidene (MeIPr) and 1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene (IDipp) in dichloromethane was investigated. MeIPr reacts relatively slowly and selectively with the solvent under the formation of imidazolium salt [MeIPrH]Cl, which was characterised through NMR and IR spectroscopy as well as single crystal X-ray diffraction. Through deuterium labelling experiments the reaction rate was determined. In contrast IDipp reacts unselectively to various imidazolium salts. Due to the slow decomposition rates of MeIPr and IDipp in CH2Cl2, reactions of the free carbenes with BeBr2 to [(MeIPr)BeBr2], [(MeIPr)2BeBr2] and [(IDipp)BeBr2] can be performed.
More Related Videos
12:19Photogeneration of N-Heterocyclic Carbenes: Application in Photoinduced Ring-Opening Metathesis Polymerization
Published on: November 29, 2018
19:58Palladium N-Heterocyclic Carbene Complexes: Synthesis from Benzimidazolium Salts and Catalytic Activity in Carbon-carbon Bond-forming Reactions
Published on: July 30, 2017
Related Concept Videos
Nucleophilic Aromatic Substitution: Elimination–Addition
Halogenation of Alkenes
Consider the bromination of cyclopentene. Molecular bromine is polarized in the proximity of the π electrons of cyclopentene. An electrophilic bromine atom adds across the double bond, forming a cyclic bromonium ion intermediate.
Electrophilic Aromatic Substitution: Chlorination and Bromination of Benzene
Carboxylic Acids to Methylesters: Alkylation using Diazomethane
Radical Substitution: Halogenation of Alkanes and Alkyl Substituents
In the initiation step of the reaction, the chlorine molecule undergoes homolytic cleavage in the presence of light or heat, forming two highly reactive chlorine radicals. Propagation occurs in two...
ortho–para-Directing Activators: –CH3, –OH, –⁠NH2, –OCH3