Search research articles

ABOUT JoVE

Overview Leadership Blog JoVE Help Center

AUTHORS

Publishing Process Editorial Board Scope & Policies Peer Review FAQ Submit

LIBRARIANS

Testimonials Subscriptions Access Resources Library Advisory Board FAQ

RESEARCH

JoVE Journal Methods Collections JoVE Encyclopedia of Experiments Archive

EDUCATION

JoVE Core JoVE Business JoVE Science Education JoVE Lab Manual Faculty Resource Center Faculty Site

Terms & Conditions of Use

Related Concept Videos

Halogens

Halogens

Group 17 elements, known as halogens, are nonmetals. At room temperature, fluorine and chlorine are gases, bromine is a liquid, and iodine a solid. Astatine is a highly unstable radioactive element, so currently, most of its properties are unknown due to its short half-life. Tennessine is a synthetic element also predicted to be in this group.

Formation of Halohydrin from Alkenes

Formation of Halohydrin from Alkenes

An alkene, such as propene, reacts with bromine in the presence of water to yield a halohydrin. Halohydrins contain a halogen and a hydroxyl group attached to adjacent carbons. When the halogen is bromine, it is called a bromohydrin, while a chlorohydrin has chlorine as the halogen.

Radical Halogenation: Thermodynamics

Radical Halogenation: Thermodynamics

The thermodynamic favorability of a reaction is determined by the change in Gibbs free energy (ΔG). ΔG has two components- enthalpy (ΔH) and entropy (ΔS). The entropy component is negligible for alkane halogenation because the number of reactants and product molecules are equal. In this case, the ΔG is governed only by the enthalpy component. The most crucial factor that determines ΔH is the strength of the bonds. ΔH can be determined by comparing the energy...

ortho–para-Directing Deactivators: Halogens

ortho–para-Directing Deactivators: Halogens

Halogens are ortho–para directors. They are more electronegative than carbon. Therefore, as ring substituents, they can withdraw electrons through the inductive effect and deactivate the aromatic ring towards electrophilic substitution. Halogens also have an electron-donating resonance effect on the ring, which influences the orientation of the incoming electrophile. If an electrophile attacks at the ortho or the para position, the halogen donates electrons and stabilizes the intermediate...

Halogenation of Alkenes

Halogenation of Alkenes

Halogenation is the addition of chlorine or bromine across the double bond in an alkene to yield a vicinal dihalide. The reaction occurs in the presence of inert and non-nucleophilic solvents, such as methylene chloride, chloroform, or carbon tetrachloride.
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 1,2- and 1,4-Addition of X2 to 1,3-Butadiene

Electrophilic 1,2- and 1,4-Addition of X₂ to 1,3-Butadiene

Electrophilic addition of halogens to alkenes proceeds via a cyclic halonium ion to form a 1,2-dihalide or a vicinal dihalide.

You might also read

Related Articles

Articles linked to this work by shared authors, journal, and citation graph.

Sort by

Same author

Examining mindfulness as a strategy to improve the exercise experience.

Journal of sports sciences·2024

Same author

Beyond Rubik: The Embodiment-Presence-Interactivity Cube applied to exercise.

Psychology of sport and exercise·2024

Same author

Synthesis of Heterocycle-Substituted Bicyclo[3.1.1]heptanes and Aza-bicyclo[3.1.1]heptanes via Photocatalytic Minisci Reaction.

Organic letters·2024

Same author

A systematic narrative review of extrinsic strategies to improve affective responses to exercise.

Frontiers in sports and active living·2023

Same author

Affective Responses to Increasing- and Decreasing-Intensity Resistance Training Protocols.

Journal of sport & exercise psychology·2023

Same author

Green and Pleasant Lands: The Affective and Cerebral Hemodynamic Effects of Presence in Virtual Environments During Exercise.

Perceptual and motor skills·2022

Search research articles

Related Experiment Video

Updated: Mar 22, 2026

From Molecules to Materials: Engineering New Ionic Liquid Crystals Through Halogen Bonding

From Molecules to Materials: Engineering New Ionic Liquid Crystals Through Halogen Bonding

Published on: March 24, 2018

Modeling a halogen dance reaction mechanism: A density functional theory study.

Leighton Jones¹, Benjamin J Whitaker¹

¹School of Chemistry, University of Leeds, LS2 9JT, United Kingdom.

Journal of Computational Chemistry

|April 15, 2016

Summary

This study reveals the halogen dance (HD) reaction mechanism using density functional theory (DFT). SN 2 transition states are favored, with thermodynamics driving the reaction and kinetics controlling the path.

Keywords:

aromatic substitution density functional calculations molecular modeling transition states

More Related Videos

Coulomb Explosion Imaging as a Tool to Distinguish Between Stereoisomers

Coulomb Explosion Imaging as a Tool to Distinguish Between Stereoisomers

Published on: August 18, 2017

A Scalable Balz-Schiemann Reaction Protocol in a Continuous Flow Reactor

A Scalable Balz-Schiemann Reaction Protocol in a Continuous Flow Reactor

Published on: February 10, 2023

Related Experiment Videos

Last Updated: Mar 22, 2026

From Molecules to Materials: Engineering New Ionic Liquid Crystals Through Halogen Bonding

From Molecules to Materials: Engineering New Ionic Liquid Crystals Through Halogen Bonding

Published on: March 24, 2018

Coulomb Explosion Imaging as a Tool to Distinguish Between Stereoisomers

Coulomb Explosion Imaging as a Tool to Distinguish Between Stereoisomers

Published on: August 18, 2017

A Scalable Balz-Schiemann Reaction Protocol in a Continuous Flow Reactor

A Scalable Balz-Schiemann Reaction Protocol in a Continuous Flow Reactor

Published on: February 10, 2023

Area of Science:

Organic Chemistry
Computational Chemistry

Background:

The halogen dance (HD) reaction has been known for over 60 years.
Its reaction mechanism has not been previously explored using theoretical methods.

Purpose of the Study:

To investigate the halogen dance reaction mechanism using computational modeling.
To elucidate the role of lithium-halogen exchange and transition states in the HD reaction.

Main Methods:

Density functional theory (DFT) was employed to model the potential energy surface.
A thiophene substrate was used to study the reaction mechanism.

Main Results:

The lithium-halogen exchange mechanism is crucial for understanding HD.
SN 2 transition states (TS) are favored over four-center TS for lithium-bromine exchange.
Thermodynamics drives the overall HD reaction, while temperature controls the kinetic pathway.
The second SN 2 lithium-bromide TS is the rate-limiting step.
The HD reaction proceeds via a pseudo-clock mechanism involving bromide catalysis.

Conclusions:

DFT modeling provides critical insights into the HD reaction mechanism.
The reaction pathway is governed by a combination of thermodynamic and kinetic factors.
Understanding the rate-limiting step and catalytic cycle is key to controlling HD reactions.