Related Experiment Video
Updated: Feb 25, 2026
Efficient Synthesis of All-Carbon Quaternary Centers via the Conjugate Addition of Functionalized Monoorganozinc Bromides
Published on: May 26, 2019
Analysis of Reaction Processes On the Basis of the Evolution of Dynamic Orbital Forces: Examples of Cycloadditions,
Patrick Chaquin1, Franck Fuster1
1Laboratoire de Chimie Théorique, LCT, Sorbonne Universités, UPMC Univ Paris 06, CNRS UMR 7616, Paris, F-75005, France.
Abstract:
The derivative of the energy of a canonical molecular orbital (MO) [or dynamical orbital forces (DOFs)] with respect to a bond length provides a reliable index of the bonding/antibonding character of this MO on this bond. The DOFs of selected MOs as a function of the reaction coordinate were computed for a panel of model reaction mechanisms: [2+4] (Diels-Alder) cycloaddition, [2+2] cycloaddition, second-order nucleophilic substitution (SN 2), nucleophilic addition to a carbonyl group, and [1,2] hydrogen transposition. The results highlight the nature of the reorganization of the main MOs and the stage of the reaction coordinate (RC) at which it occurs. For instance, in the Diels-Alder reaction, one can identify a part of the reaction that is dominated by repulsive four-electron interactions and another part dominated by attractive two-electron interactions. Also, the shape of the DOF as a function of the reaction coordinate reveals the existence of avoided MO crossings and their location on the RC. Even for spontaneous reactions with monotonic variation in the potential energy, extrema of the MO energy and sudden electron rearrangements can be put into evidence. This study provides quantitative support to classical MO analyses of reactivity such as correlation diagrams and frontier approximation.
More Related Videos
![Mizoroki-Heck Cross-coupling Reactions Catalyzed by Dichloro{bis[1,1',1''-phosphinetriyltripiperidine]}palladium Under Mild Reaction Conditions](/_next/image?url=https%3A%2F%2Fcloudfront.jove.com%2FCDNSource%2Fteasers%2F51444.jpg&w=3840&q=50)
11:44Mizoroki-Heck Cross-coupling Reactions Catalyzed by Dichloro{bis[1,1',1''-phosphinetriyltripiperidine]}palladium Under Mild Reaction Conditions
Published on: March 20, 2014
10:52Line Shape Analysis of Dynamic NMR Spectra for Characterizing Coordination Sphere Rearrangements at a Chiral Rhenium Polyhydride Complex
Published on: July 27, 2022
Related Concept Videos
01:16Cycloaddition Reactions: Overview
02:34Nucleophilic Substitution Reactions
In 1896, the German chemist Paul Walden discovered that he could interconvert pure enantiomeric (+) and (-) malic acids through a series of reactions. This conversion suggested the involvement of optical inversion during the substitution reaction. Further, in 1930, Sir Christopher Ingold described for the first time two different forms of nucleophilic substitution reactions, which are known as SN1 (nucleophilic substitution unimolecular) and SN2 (nucleophilic substitution...
01:16Cycloaddition Reactions: MO Requirements for Thermal Activation
02:14SN2 Reaction: Kinetics
In a chemical reaction, a relationship exists between the concentration of reactants and the rate at which the reaction proceeds. The study to measure this relationship is known as the kinetics of a chemical reaction. Kinetic studies are used to deduce the rate law of a chemical reaction, which provides information about the species involved during the transition state of the rate-determining step. Thus, kinetic studies help to derive the mechanism of a...
01:17Pericyclic Reactions: Introduction
Pericyclic reactions can be classified into three categories: electrocyclic reactions, cycloaddition reactions, and sigmatropic rearrangements. Electrocyclic reactions and sigmatropic...
02:27SN2 Reaction: Mechanism
The presence of the more electronegative halogen in the substrate creates a polarized carbon-halide bond. The halide pulls the electron cloud generating an electrophilic center at the carbon atom. Thus, the carbon atom carries a partial positive charge while the halide has a...