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

Structure of Benzene: Kekulé Model

Structure of Benzene: Kekulé Model

In 1865, August Kekule suggested the structure of benzene according to the structural theory of organic chemistry based on the three assertions—formula of benzene is C6H6, all the hydrogens of benzene are equivalent, and each carbon must have four bonds due to its tetravalency.
He proposed that benzene has a cyclic structure of six carbon atoms attached to one hydrogen atom each, with three alternating pi bonds.

NMR Spectroscopy of Benzene Derivatives

NMR Spectroscopy of Benzene Derivatives

Simple unsubstituted benzene has six aromatic protons, all chemically equivalent. Therefore, benzene exhibits only a singlet peak at δ 7.3 ppm in the 1H NMR spectrum. The observed shift is far downfield because the aromatic ring current strongly deshields the protons. Any substitution on the benzene ring makes the aromatic protons nonequivalent, and the protons split each other. The peak is, therefore, no longer a singlet and the splitting pattern and their associated coupling constants depend...

Benzene to 1,4-Cyclohexadiene: Birch Reduction Mechanism

Benzene to 1,4-Cyclohexadiene: Birch Reduction Mechanism

Birch reduction uses solvated electrons as reducing agents. The reaction converts benzene to 1,4-cyclohexadiene. The reaction proceeds by the transfer of a single electron to the ring to form a benzene radical anion. This anion is highly basic—it abstracts a proton from the alcohol to form a cyclohexadienyl radical. Another single electron transfer gives the cyclohexadienyl anion. A proton transfer from the alcohol forms 1,4-cyclohexadiene. Since this reduction occurs via radical anion...

Electrophilic Aromatic Substitution: Nitration of Benzene

Electrophilic Aromatic Substitution: Nitration of Benzene

The nitration of benzene is an example of an electrophilic aromatic substitution reaction. It involves the formation of a very powerful electrophile, the nitronium ion, which is linear in shape. The reaction occurs through the interaction of two strong acids, sulfuric and nitric acid.

Electrophilic Aromatic Substitution: Sulfonation of Benzene

Electrophilic Aromatic Substitution: Sulfonation of Benzene

Sulfonation of benzene is a reaction wherein benzene is treated with fuming sulfuric acid at room temperature to produce benzenesulfonic acid. Fuming sulfuric acid is a mixture of sulfur trioxide and concentrated sulfuric acid.

Nucleophilic Aromatic Substitution: Elimination–Addition

Nucleophilic Aromatic Substitution: Elimination–Addition

Simple aryl halides do not react with nucleophiles. However, nucleophilic aromatic substitutions can be forced under certain conditions, such as high temperatures or strong bases. The mechanism of substitution under such conditions involves the highly unstable and reactive benzyne intermediate. Benzyne contains equivalent carbon centers at both ends of the triple bond, each of which is equally susceptible to nucleophilic attack. This 50–50 distribution of products is confirmed through isotopic...

You might also read

Related Articles

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

Sort by

Same author

Isolation, Antioxidant Activity, and Reaction Mechanism of Chamazulene from <i>Artemisia selengensis</i> Turcz. ex Besser Essential Oil.

ACS omega·2026

Same author

Solvatofluorochromic Behavior of Naphthalene-Based π-Conjugated Compounds Governed by Intramolecular Charge Transfer.

Chemistry, an Asian journal·2026

Same author

Comprehensive Bibliometric Analysis of Uremic Toxin Research.

Toxins·2025

Same author

Direct Hemoperfusion with Polymethylmethacrylate for Hemodialysis Patients with Dialysis-Related Amyloidosis.

Blood purification·2025

Same author

Ectopic Production of Parathyroid Hormone and Production of Parathyroid Hormone-related Protein in Dedifferentiated Endometrial Carcinoma Induced Severe Hypercalcemia.

Internal medicine (Tokyo, Japan)·2024

Same author

Circularly polarised luminescence from intramolecular excimer emission of bis-1,8-naphthalimide derivatives.

Organic & biomolecular chemistry·2024

Search research articles

Related Experiment Video

Updated: Jun 19, 2026

Palladium N-Heterocyclic Carbene Complexes: Synthesis from Benzimidazolium Salts and Catalytic Activity in Carbon-carbon Bond-forming Reactions

Palladium N-Heterocyclic Carbene Complexes: Synthesis from Benzimidazolium Salts and Catalytic Activity in Carbon-carbon Bond-forming Reactions

Published on: July 30, 2017

pi Complexes in benzidine rearrangement.

Shinichi Yamabe¹, Hazuki Nakata, Shoko Yamazaki

¹Department of Chemistry, Nara University of Education, Takabatake-cho, Nara 630-8528, Japan. yamabes@nara-edu.ac.jp

Organic & Biomolecular Chemistry

|October 30, 2009

Summary

This study reveals the unknown mechanism of the title rearrangement using DFT calculations. It identifies transient intermediates and clarifies the reaction pathway, reviving a previously dismissed pi complex theory.

More Related Videos

Isolating Free Carbenes, their Mixed Dimers and Organic Radicals

Isolating Free Carbenes, their Mixed Dimers and Organic Radicals

Published on: April 19, 2019

[(DPEPhos)(bcp)Cu]PF6: A General and Broadly Applicable Copper-Based Photoredox Catalyst

[(DPEPhos)(bcp)Cu]PF₆: A General and Broadly Applicable Copper-Based Photoredox Catalyst

Published on: May 21, 2019

Related Experiment Videos

Last Updated: Jun 19, 2026

Palladium N-Heterocyclic Carbene Complexes: Synthesis from Benzimidazolium Salts and Catalytic Activity in Carbon-carbon Bond-forming Reactions

Palladium N-Heterocyclic Carbene Complexes: Synthesis from Benzimidazolium Salts and Catalytic Activity in Carbon-carbon Bond-forming Reactions

Published on: July 30, 2017

Isolating Free Carbenes, their Mixed Dimers and Organic Radicals

Isolating Free Carbenes, their Mixed Dimers and Organic Radicals

Published on: April 19, 2019

[(DPEPhos)(bcp)Cu]PF6: A General and Broadly Applicable Copper-Based Photoredox Catalyst

[(DPEPhos)(bcp)Cu]PF₆: A General and Broadly Applicable Copper-Based Photoredox Catalyst

Published on: May 21, 2019

Area of Science:

Computational Chemistry
Organic Reaction Mechanisms
Physical Organic Chemistry

Background:

The title rearrangement, a classical reaction known since 1862, possesses an largely unknown reaction mechanism.
Complexities include variable rate orders, product distribution, and difficult-to-interpret kinetic isotope effects for substituted hydrazobenzenes.

Purpose of the Study:

To elucidate the detailed reaction mechanism of the title rearrangement for the first time.
To investigate the role of transient intermediates and explore proposed reaction pathways, including Dewar's pi complex.

Main Methods:

Density Functional Theory (DFT) calculations were employed to model the reaction.
A specific reaction model incorporating hydronium ions (H3O+) and water molecules (H2O) was utilized to trace the reaction path.

Main Results:

Transient intermediates were identified during the main reaction pathway, leading to the formation of the diphenyline product.
The Claisen shift pathway was found for H+ protonation, while Dewar's proposed pi complex was not observed in the parent system.
However, the calculations revealed the presence of a pi complex in dimethoxyhydrazobenzene, suggesting a revival of Dewar's theory.

Conclusions:

The study provides unprecedented insight into the mechanism of the title rearrangement.
DFT calculations clarify the formation of diphenyline and offer a re-evaluation of Dewar's pi complex theory in specific substituted systems.