Related Experiment Video
Updated: Oct 25, 2026

Isolating Free Carbenes, their Mixed Dimers and Organic Radicals
Published on: April 19, 2019
N-Heterocyclic Carbene-Carbodiimide (NHC-CDI) Adducts as a Tunable Scaffold for Distonic Radical Cation and Dication
Rolando Calderón-Oliver1, Le Dung Pham1, Anthony W Schlimgen1
1Department of Chemistry, University of Minnesota-Twin Cities, 207 Pleasant Street SE, Minneapolis, Minnesota55455, United States.
Abstract:
Reactive organic intermediates─particularly radical cations and dications─possess unique structural and electronic properties significant for the advancement of fundamental chemistry and materials. However, stabilizing motifs for these highly reactive species have limited synthetic accessibility and tunability. N-Heterocyclic carbene-carbodiimide (NHC-CDI) adducts are a promising platform to stabilize these intermediates due to their tunability and synthetic accessibility. Herein, we report a simple NHC-CDI framework─containing substituted diphenyl CDIs with one radical stabilizer (4-dimethylamino) and one tunable handle─that can stabilize distonic radical cation and dication species. We synthesized six systematically varied adducts that undergo two sequential oxidations with half-wave potentials (E1/2,1 = -0.528 to -0.205 V; E1/2,2 = -0.005 to +0.115 V) correlating strongly to the electronics of the CDI (i.e., Hammett (σp) parameters). Electrochemical studies confirmed each redox event as a reversible, one-electron, and diffusion-controlled process. Additionally, spectroscopic experiments of a chemically oxidized NHC-CDI support the formation and stability of the radical cation and dication species. The facile synthetic tunability and accessibility make this platform promising for the study and development of reactive intermediates for catalysis and energy materials.
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
Aromatic Hydrocarbon Cations: Structural Overview
Removing one hydrogen from the intervening CH2 group with both...
Carbocations
[4+2] Cycloaddition of Conjugated Dienes: Diels–Alder Reaction
Radicals: Electronic Structure and Geometry
Accordingly, the structure of a trivalent radical lies between the geometries of carbocations and carbanions. An sp2-hybridized carbocation is trigonal planar, while an sp3-hybridized carbanion is trigonal pyramidal. Here, the difference in geometry is...
Radical Reactivity: Steric Effects
Along with electronic factors, steric factors also account...
Radical Reactivity: Intramolecular vs Intermolecular