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

meta-Directing Deactivators: –NO2, –CN, –CHO, –&NoBreak;CO2R, –COR, –CO2H

meta-Directing Deactivators: –NO₂, –CN, –CHO, –⁠CO₂R, –COR, –CO₂H

All meta-directing substituents are deactivating groups. These substituents withdraw electrons from the aromatic ring, making the ring less reactive toward electrophilic substitution. For example, the nitration of nitrobenzene is 100,000 times slower than that of benzene because of the deactivating effect of the nitro group. The first step in an electrophilic aromatic substitution is the addition of an electrophile to form a resonance-stabilized carbocation. The energy diagrams for...

2° Amines to N-Nitrosamines: Reaction with NaNO2

2° Amines to N-Nitrosamines: Reaction with NaNO₂

Secondary amines react with nitrous acid to form N-nitrosamines, as depicted in Figure 1. Nitrous acid, a weak and unstable acid, is formed in situ from an aqueous solution of sodium nitrite and strong acids, such as hydrochloric acid or sulfuric acid, in cold conditions. In the presence of an acid, the nitrous acid gets protonated. The subsequent loss of water results in the formation of the electrophile known as nitrosonium ion.

SN2 Reaction: Kinetics

S_N2 Reaction: Kinetics

Kinetic Studies and Significance
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...

SN2 Reaction: Mechanism

S_N2 Reaction: Mechanism

The kinetic studies of SN2 reactions suggest an essential feature of its mechanism: it is a single-step process without intermediates. Here, both the nucleophile and the substrate participate in the rate-determining step.
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...

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...

SN2 Reaction: Stereochemistry

S_N2 Reaction: Stereochemistry

In an SN2 reaction, the nucleophilic attack on the substrate and departure of the leaving group occurs simultaneously through a transition state. As the nucleophile approaches the substrate from the back-side, the configuration of the substrate carbon changes from tetrahedral to trigonal bipyramidal and then back to tetrahedral, leading to an inversion in the configuration of the product.
If the substrate is an achiral molecule at the α-carbon, the inversion of configuration is not...

You might also read

Related Articles

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

Sort by

Same author

Near-Infrared-Driven Multiplexed, Self-Powered Photoelectrochemical Sensor for Portable and Reliable Detection of Steroid Estrogens.

Analytical chemistry·2026

Same author

Perioperative serplulimab with neoadjuvant chemotherapy versus perioperative chemotherapy in PD-L1-positive gastric cancer (ASTRUM-006): a randomised, double-blind, multicentre, phase 3 study.

Lancet (London, England)·2026

Same author

Real-World Treatment Patterns, HER2 Testing Practices, and Clinical Outcomes in HER2-Positive Locally Advanced or Metastatic Gastric or Gastroesophageal Junction Cancer.

Advances in therapy·2026

Same author

Zanidatamab with and without Tislelizumab in HER2-Positive Gastroesophageal Cancer.

The New England journal of medicine·2026

Same author

Regional and national burden of six major digestive cancers in Asia, 1990-2023: An analysis of the GBD Study 2023.

iScience·2026

Same author

Aerobic extracellular electron transfer in Shewanella spp.

Bioresource technology·2026

Search research articles

Related Experiment Video

Updated: Feb 11, 2026

Synthesis and Functionalization of Nitrogen-doped Carbon Nanotube Cups with Gold Nanoparticles as Cork Stoppers

Synthesis and Functionalization of Nitrogen-doped Carbon Nanotube Cups with Gold Nanoparticles as Cork Stoppers

Published on: May 13, 2013

A gold-nanoparticle stoppered [2]rotaxane.

Anne Ulfkjær¹, Frederik W Nielsen, Hana Al-Kerdi

¹Department of Chemistry, University of Copenhagen, Universitetsparken 5, DK-2100 Copenhagen, Denmark. pittel@chem.ku.dk.

|May 4, 2018

Summary

This summary is machine-generated.

Scientists created a novel molecular machine by interfacing mechanically interlocked molecules with gold nanoparticles. This breakthrough mimics biological machinery using artificial nanostructures for advanced applications.

More Related Videos

Gold Nanoparticle Synthesis

Gold Nanoparticle Synthesis

Published on: July 10, 2021

Synthesis and Characterization of Amphiphilic Gold Nanoparticles

Synthesis and Characterization of Amphiphilic Gold Nanoparticles

Published on: July 2, 2019

Related Experiment Videos

Last Updated: Feb 11, 2026

Synthesis and Functionalization of Nitrogen-doped Carbon Nanotube Cups with Gold Nanoparticles as Cork Stoppers

Synthesis and Functionalization of Nitrogen-doped Carbon Nanotube Cups with Gold Nanoparticles as Cork Stoppers

Published on: May 13, 2013

Gold Nanoparticle Synthesis

Gold Nanoparticle Synthesis

Published on: July 10, 2021

Synthesis and Characterization of Amphiphilic Gold Nanoparticles

Synthesis and Characterization of Amphiphilic Gold Nanoparticles

Published on: July 2, 2019

Area of Science:

Supramolecular Chemistry
Nanotechnology
Molecular Engineering

Background:

Molecular machines are crucial for life's functions, inspiring artificial nanostructure development.
Mechanically interlocked molecules (MIMs) are key components in natural and synthetic molecular machines.
Integrating small-molecule components into functional devices remains a significant challenge.

Purpose of the Study:

To interface mechanically interlocked molecules with gold nanoparticles (AuNPs).
To develop a molecular wire with an insulating rotaxane layer, mimicking macroscopic electrical wires.
To create a functional nano-device using supramolecular chemistry principles.

Main Methods:

Preparation of a bis-thiol functionalized pseudo-rotaxane using cucurbit[7]uril (CB[7]) macrocycles.
Formation of AuNP-stoppered [2]rotaxanes in aqueous media.
Characterization using NMR spectroscopy, mass spectrometry, and electrochemistry.

Main Results:

A stable AuNP-stoppered [2]rotaxane was successfully synthesized in water.
The pseudo-rotaxane demonstrated extremely tight binding (association constant Ka > 10^13 M^-1).
Electrochemical studies revealed detailed guest-host interactions with and without CB[7] and AuNPs.

Conclusions:

This work presents a novel approach to constructing molecular machines by integrating MIMs and AuNPs.
The developed system offers a platform for studying and designing advanced functional nanostructures.
The findings pave the way for mimicking biological machinery with artificial components.