Related Experiment Video
Updated: Jul 6, 2026

A Two-Step Protocol for Umpolung Functionalization of Ketones Via Enolonium Species
Published on: August 16, 2018
Tuning the nucleophilicity in cyclopropenylidenes
Wolfgang W Schoeller1, Guido D Frey, Guy Bertrand
1Fakultät für Chemie der Universität, Universität Bielefeld, Bielefeld, Germany. wolfgang.schoeller@ucr.edu
Cyclopropenylidenes, aromatic pi systems with carbene centers, exhibit significant singlet-triplet energy gaps influenced by substituents. These compounds can be stabilized to prevent dimerization and tuned for enhanced nucleophilicity.
Area of Science:
- Organic Chemistry
- Computational Chemistry
- Quantum Chemistry
Background:
- Cyclopropenylidenes are Hückel aromatic pi systems featuring a carbene center.
- Understanding their electronic structure and reactivity is crucial for synthetic applications.
Purpose of the Study:
- To investigate the electronic properties and stability of cyclopropenylidenes using computational methods.
- To explore the influence of substituents on the singlet-triplet energy gap and dimerization potential.
- To assess the potential for tuning cyclopropenylidenes' nucleophilicity.
Main Methods:
- Density Functional Theory (DFT) calculations.
- Coupled-Cluster (CC) calculations for high accuracy.
- Investigation of various substituents (alkyl, silyl, amino, etc.).
Main Results:
- A sizeable energy separation exists between singlet and triplet states of cyclopropenylidenes.
- Amino groups increase this energy gap, while electron-withdrawing groups decrease it.
- Substituents can stabilize cyclopropenylidenes against kinetically driven dimerization to triafulvalenes.
Conclusions:
- Cyclopropenylidenes' stability and reactivity are tunable via substituent choice.
- Strategic substitution can enhance cyclopropenylidenes' nucleophilicity beyond imidazol-2-ylidenes.
- These findings open avenues for designing novel reactive intermediates.
More Related Videos
09:45Accessing Valuable Ligand Supports for Transition Metals: A Modified, Intermediate Scale Preparation of 1,2,3,4,5-Pentamethylcyclopentadiene
Published on: March 20, 2017
10:17Efficient Construction of Drug-like Bispirocyclic Scaffolds Via Organocatalytic Cycloadditions of α-Imino γ-Lactones and Alkylidene Pyrazolones
Published on: February 7, 2019
Related Concept Videos
Conformations of Cycloalkanes
Cycloaddition Reactions: Overview
Aromatic Hydrocarbon Anions: Structural Overview
Due to the absence of continuous overlap of p...
Diels–Alder Reaction: Characteristics of Dienophiles
Characteristics of Dienophiles
Generally, the best dienophiles are alkenes containing electron-withdrawing substituents such as carbonyl, nitrile, and nitro groups. The feasibility of a Diels–Alder reaction depends on...
ortho–para-Directing Activators: –CH3, –OH, –⁠NH2, –OCH3
Prochirality