Jove
Visualize
Contact Us
JoVE
x logofacebook logolinkedin logoyoutube logo
ABOUT JoVE
OverviewLeadershipBlogJoVE Help Center
AUTHORS
Publishing ProcessEditorial BoardScope & PoliciesPeer ReviewFAQSubmit
LIBRARIANS
TestimonialsSubscriptionsAccessResourcesLibrary Advisory BoardFAQ
RESEARCH
JoVE JournalMethods CollectionsJoVE Encyclopedia of ExperimentsArchive
EDUCATION
JoVE CoreJoVE BusinessJoVE Science EducationJoVE Lab ManualFaculty Resource CenterFaculty Site
Terms & Conditions of Use
Privacy Policy
Policies

Related Concept Videos

Basicity of Heterocyclic Aromatic Amines01:25

Basicity of Heterocyclic Aromatic Amines

Heterocyclic amines, where the N atom is a part of an alicyclic system, are similar in basicity to alkylamines. Interestingly, the heterocyclic amine having a nitrogen atom as part of an aromatic ring has much less basicity than its corresponding alicyclic counterpart. For this reason, as presented in Figure 1, piperidine (pKb = 2.8) is significantly more basic than pyridine (pKb = 8.8).
Structure of Amines01:19

Structure of Amines

The hybridized nitrogen atom in amines possesses a lone pair of electrons and is bound to three substituents with a bond angle of around 108°, which is less than the tetrahedral angle of 109.5°. However, the C–N–H bond angle is slightly larger at 112°, with a carbon–nitrogen bond length of 147 pm. This carbon–nitrogen bond length of of amines is longer than the carbon–oxygen bond of alcohols (143 pm) but shorter than alkanes’ carbon–carbon bond (154 pm). These aspects are illustrated in Figure...
Basicity of Aliphatic Amines01:21

Basicity of Aliphatic Amines

Amines can behave as Brønsted–Lowry bases by accepting a proton from the acid to form corresponding conjugate acids. Due to a lone pair of nonbonding electrons, aliphatic amines can also act as Lewis bases by forming a covalent bond with an electrophile.
To measure the basicity of amines, two conventions are generally used. The first defines Kb as the basicity constant for the deprotonation reaction of water by the amine, as presented in Figure 1. Conventionally, lower Kb indicates higher...
Physical Properties of Amines01:26

Physical Properties of Amines

Amines with low molecular weight are usually gaseous at room temperature, while those with high molecular weight are liquid or solids in nature. Usually, low molecular weight amines have a rotten fish-like smell. Diamines typically have a pungent smell. For instance, cadaverine and putrescine, depicted in Figure 1, are two molecules responsible for decaying tissue.
Aldehydes and Ketones with Amines: Imine Formation Mechanism01:23

Aldehydes and Ketones with Amines: Imine Formation Mechanism

Imine formation involves the addition of carbonyl compounds to a primary amine. It begins with the generation of carbinolamine through a series of steps involving an initial nucleophilic attack and then several proton transfer reactions. The second part includes the elimination of water, as a leaving group, to give the imine.
Imines are formed under mildly acidic conditions. A pH of 4.5 is ideal for the reaction.
If the pH is low or the solution is too acidic, the reaction slows down in the...
Basicity of Aromatic Amines01:18

Basicity of Aromatic Amines

The basicity of aromatic amines is much weaker than that of aliphatic amines due to the involvement of the lone pair of electrons over the N atom in resonance with the aryl rings. Generally, the electron-donating ability of any substituents on the aryl ring of aromatic amines increases the basicity of the amine by increasing electron density, and hence the availability of lone pair on the nitrogen. On the other hand, electron-withdrawing functional groups on the aryl ring of amines decrease the...

You might also read

Related Articles

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

Sort by
Same author

Primitive Basic Amino Acids Promote Mineral-Catalyzed Electrochemical Reduction of H<sup>+</sup> and CO<sub>2</sub>.

The journal of physical chemistry. C, Nanomaterials and interfaces·2026
Same author

Preserved Antegrade Pulmonary Blood Flow in Bidirectional Glenn: Outcomes and Considerations for Staged Palliation.

The Annals of thoracic surgery·2026
Same author

<sup>16</sup>O poor cosmic spherules from near-Earth CY chondrite asteroids.

Science advances·2026
Same author

An amperometric l-citrulline biosensor.

Bioelectrochemistry (Amsterdam, Netherlands)·2026
Same author

When wet meets dry: An Ivuna-like impactor triggered volatile loss on the angrite parent body.

Science advances·2026
Same author

Pyrrhotite-driven early-stage terrestrial alteration in Ryugu grains.

Nature communications·2026

Related Experiment Video

Updated: Jun 3, 2026

Preparation of Functional Silica Using a Bioinspired Method
08:04

Preparation of Functional Silica Using a Bioinspired Method

Published on: August 1, 2018

Acid-base equilibria inside amine-functionalized mesoporous silica.

Akira Yamaguchi1, Manato Namekawa, Toshio Kamijo

  • 1College of Science and Frontier Research Center for Applied Atomic Sciences, Ibaraki University, 2-1-1 Bunkyo, Mito, Ibaraki 310-8512, Japan. yakira@mx.ibaraki.ac.jp

Analytical Chemistry
|March 23, 2011
PubMed
Summary

This study investigated proton concentration within trimethyl ammonium (TMAP)-modified silica mesopores using fluorescence. Results show pore pH differs from bulk pH, indicating altered acid-base equilibria in confined environments.

More Related Videos

A Synthetic Methodology for Preparing Impregnated and Grafted Amine-Based Silica Composites for Carbon Capture
08:00

A Synthetic Methodology for Preparing Impregnated and Grafted Amine-Based Silica Composites for Carbon Capture

Published on: September 29, 2023

Imine Metathesis by Silica-Supported Catalysts Using the Methodology of Surface Organometallic Chemistry
09:37

Imine Metathesis by Silica-Supported Catalysts Using the Methodology of Surface Organometallic Chemistry

Published on: October 18, 2019

Related Experiment Videos

Last Updated: Jun 3, 2026

Preparation of Functional Silica Using a Bioinspired Method
08:04

Preparation of Functional Silica Using a Bioinspired Method

Published on: August 1, 2018

A Synthetic Methodology for Preparing Impregnated and Grafted Amine-Based Silica Composites for Carbon Capture
08:00

A Synthetic Methodology for Preparing Impregnated and Grafted Amine-Based Silica Composites for Carbon Capture

Published on: September 29, 2023

Imine Metathesis by Silica-Supported Catalysts Using the Methodology of Surface Organometallic Chemistry
09:37

Imine Metathesis by Silica-Supported Catalysts Using the Methodology of Surface Organometallic Chemistry

Published on: October 18, 2019

Area of Science:

  • Materials Science
  • Physical Chemistry
  • Nanotechnology

Background:

  • Mesoporous silica materials offer unique confinement effects.
  • Surface modification of silica can alter chemical properties.
  • Understanding confined acid-base chemistry is crucial for applications.

Purpose of the Study:

  • To investigate acid-base equilibria and effective proton concentration within trimethyl ammonium (TMAP)-modified silica mesopores.
  • To compare the behavior of pH indicator dyes in confined mesopores versus bulk solution.
  • To establish relationships between bulk solution pH and the effective pore pH.

Main Methods:

  • Steady-state fluorescence spectroscopy was employed.
  • Anionic fluorescence indicator dyes (pyranine, APTS, TPPS, 2NT) were used.
  • Mesoporous silica was functionalized with a dense TMAP layer.

Main Results:

  • Acid-base equilibria of dyes within TMAP-modified mesopores differed significantly from bulk water.
  • A specific relationship was found between bulk pH and effective pore pH for pyranine.
  • The TMAP-modified mesopore interior exhibited a weakly acidic to neutral condition across a wide bulk pH range.

Conclusions:

  • The effective proton concentration inside TMAP-modified silica mesopores is distinct from bulk solution.
  • Established relationships between bulk and pore pH explain the behavior of various pH indicators.
  • This work provides insights into confined chemical environments within functionalized nanomaterials.