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

SN2 Reaction: Transition State

S_N2 Reaction: Transition State

An SN2 reaction of an alkyl halide is a single-step process in which bond formation between the nucleophile and the substrate and bond breaking between the substrate and the halide occurs simultaneously through a transition state without forming an intermediate.
When the nucleophile approaches the electrophilic carbon with its lone pairs, the halide acts as a leaving group and moves away with the electron-pair bonded to the carbon. Dotted partial bonds represent the bonds being formed or broken...

Preparation and Reactions of Sulfides

Preparation and Reactions of Sulfides

Sulfides are the sulfur analog of ethers, just as thiols are the sulfur analog of alcohol. Like ethers, sulfides also consist of two hydrocarbon groups bonded to the central sulfur atom. Depending upon the type of groups present, sulfides can be symmetrical or asymmetrical. Symmetrical sulfides can be prepared via an SN2 reaction between 2 equivalents of an alkyl halide and one equivalent of sodium sulfide.

You might also read

Related Articles

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

Sort by

Same author

Effect of Salt Additives on Dinitrogen Activation Mediated by Boron-Based Compounds: Insights from Theory.

Inorganic chemistry·2026

Same author

Asymmetric α-Alkylation With Activated and Unactivated Electrophiles by a Highly Productive and Recyclable Lewis Acid/Imidazolium Catalyst.

Angewandte Chemie (International ed. in English)·2026

Same author

How to Train a Shallow Ensemble.

Journal of chemical theory and computation·2026

Same author

Fibroblast growth factor 23 is associated with cardiac disease severity in transthyretin amyloid cardiomyopathy.

Scientific reports·2026

Same author

Desorption dynamics of interstellar molecule on amorphous solid water investigated by machine learning potential-based PaCS-MD simulation.

The Journal of chemical physics·2026

Same author

Insights into the renin-angiotensin-aldosterone system in transthyretin amyloid cardiomyopathy.

European journal of heart failure·2026

Search research articles

Related Experiment Video

Updated: Jul 8, 2026

Synthesis of a Thiol Building Block for the Crystallization of a Semiconducting Gyroidal Metal-sulfur Framework

Synthesis of a Thiol Building Block for the Crystallization of a Semiconducting Gyroidal Metal-sulfur Framework

Published on: April 9, 2018

Superlinearly converging dimer method for transition state search.

Johannes Kästner¹, Paul Sherwood

¹Computational Science and Engineering Department, STFC Daresbury Laboratory, Daresbury, Warrington WA4 4AD, United Kingdom. j.kaestner@dl.ac.uk

The Journal of Chemical Physics

|January 15, 2008

Summary

This study enhances the dimer method for locating transition states using the L-BFGS optimizer, improving convergence and reducing computational cost. The optimized method efficiently finds transition states, especially in large systems, without needing Hessian calculations.

More Related Videos

Applying Cheminformatics to Develop a Structure Searchable Database of Analytical Methods

Applying Cheminformatics to Develop a Structure Searchable Database of Analytical Methods

Published on: June 6, 2025

Preparation of Contiguous Bisaziridines for Regioselective Ring-Opening Reactions

Preparation of Contiguous Bisaziridines for Regioselective Ring-Opening Reactions

Published on: July 28, 2022

Related Experiment Videos

Last Updated: Jul 8, 2026

Synthesis of a Thiol Building Block for the Crystallization of a Semiconducting Gyroidal Metal-sulfur Framework

Synthesis of a Thiol Building Block for the Crystallization of a Semiconducting Gyroidal Metal-sulfur Framework

Published on: April 9, 2018

Applying Cheminformatics to Develop a Structure Searchable Database of Analytical Methods

Applying Cheminformatics to Develop a Structure Searchable Database of Analytical Methods

Published on: June 6, 2025

Preparation of Contiguous Bisaziridines for Regioselective Ring-Opening Reactions

Preparation of Contiguous Bisaziridines for Regioselective Ring-Opening Reactions

Published on: July 28, 2022

Area of Science:

Computational Chemistry
Chemical Physics

Background:

The dimer method is a computational technique for finding transition states in chemical reactions.
Previous implementations relied on conjugate gradient algorithms, which could be slow to converge.

Purpose of the Study:

To improve the efficiency and convergence of the dimer method for transition state searches.
To reduce the computational cost associated with finding transition states, particularly for large molecular systems.

Main Methods:

Implemented the limited memory Broyden-Fletcher-Goldfarb-Shanno (L-BFGS) optimizer for dimer translation and rotation.
Utilized extrapolation of gradients during dimer rotations to decrease computational expense.
Applied the dimer method in internal coordinates with optional coordinate weighting.

Main Results:

The L-BFGS optimizer significantly improved convergence rates compared to conjugate gradient methods.
Computational cost was reduced, requiring fewer energy and gradient evaluations per iteration.
The method demonstrated efficiency in locating transition states without Hessian calculations, even in large systems.

Conclusions:

The enhanced dimer method offers a more efficient approach for transition state searches.
This method is particularly advantageous for large molecular systems where gradient evaluations are computationally expensive.
The improvements facilitate the study of reaction mechanisms in complex chemical systems.