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Related Concept Videos

Electrophilic Aromatic Substitution: Nitration of Benzene01:20

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.
2° Amines to N-Nitrosamines: Reaction with NaNO201:20

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.
1° Amines to Diazonium or Aryldiazonium Salts: Diazotization with NaNO2 Overview01:26

1° Amines to Diazonium or Aryldiazonium Salts: Diazotization with NaNO2 Overview

Nitrous acid and nitric acids are two types of acids containing nitrogen, among which nitrous acid is weaker than nitric acid. Nitrous acid with a pKa value of 3.37 ionizes in water to give a nitrite ion and the hydronium ion.
The nitrous acid is unstable. Hence, it is formed in situ from a solution of sodium nitrite and cold aqueous acids such as hydrochloric or sulfuric acid. In an acidic solution, the –OH group of nitrous acid undergoes protonation to give oxonium ion, followed by water loss...
1° Amines to Diazonium or Aryldiazonium Salts: Diazotization with NaNO2 Mechanism01:37

1° Amines to Diazonium or Aryldiazonium Salts: Diazotization with NaNO2 Mechanism

Nitrous acid is a relatively weak and unstable acid prepared in situ by the reaction of sodium nitrite and cold, dilute hydrochloric acid. In an acidic solution, the nitrous acid undergoes protonation when it loses water to form a nitrosonium ion—an electrophile. Nitrous acid reacts with primary amines to give diazonium salts. The reaction is called diazotization of primary amines.
Diazonium Group Substitution: –OH and –H01:19

Diazonium Group Substitution: –OH and –H

Nitrous acid, a weak acid, is prepared in situ via the reaction of sodium nitrite with a strong acid under cold conditions. This nitrous acid prepared in situ reacts with primary arylamines to form arenediazonium salts. Such reactions are known as diazotization reactions. As shown in Figure 1, the formation of arenediazonium salts begins with the decomposition of nitrous acid in an acidic solution to give nitrosonium ions.
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.

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A Direct, Regioselective and Atom-Economical Synthesis of 3-Aroyl-N-hydroxy-5-nitroindoles by Cycloaddition of 4-Nitronitrosobenzene with Alkynones
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A Direct, Regioselective and Atom-Economical Synthesis of 3-Aroyl-N-hydroxy-5-nitroindoles by Cycloaddition of 4-Nitronitrosobenzene with Alkynones

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3-Nitro-benzene-1,2-diamine.

Richard Betz1, Thomas Gerber

  • 1Nelson Mandela Metropolitan University, Summerstrand Campus, Department of Chemistry, University Way, Summerstrand, PO Box 77000, Port Elizabeth 6031, South Africa.

Acta Crystallographica. Section E, Structure Reports Online
|July 15, 2011
PubMed
Summary
This summary is machine-generated.

This study details the crystal structure of a C(6)H(7)N(3)O(2) compound, an o-phenyl-enediamine derivative. Molecules form undulating sheets via hydrogen bonds, with no observed pi-stacking in the crystal lattice.

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Area of Science:

  • Crystallography
  • Organic Chemistry
  • Materials Science

Background:

  • o-phenyl-enediamine derivatives are important in various chemical applications.
  • Understanding molecular symmetry and intermolecular interactions is crucial for predicting material properties.

Purpose of the Study:

  • To elucidate the crystal structure of the title compound, C(6)H(7)N(3)O(2).
  • To analyze the molecular symmetry and hydrogen bonding network within the crystal lattice.
  • To investigate the presence or absence of pi-stacking interactions.

Main Methods:

  • Single-crystal X-ray diffraction was employed to determine the molecular and crystal structure.
  • Analysis of bond angles and distances to assess molecular geometry.
  • Identification and characterization of intermolecular and intramolecular hydrogen bonds.

Main Results:

  • The molecule exhibits near non-crystallographic C(s) symmetry.
  • Intermolecular N-H⋯O and N-H⋯N hydrogen bonds form undulating sheets perpendicular to the a axis.
  • A weak intramolecular N-H⋯O hydrogen bond was identified; no pi-stacking was observed.

Conclusions:

  • The crystal structure is stabilized by a network of hydrogen bonds, forming sheet-like arrangements.
  • The absence of pi-stacking suggests specific packing forces dominate.
  • The findings provide a structural basis for understanding the physical properties of this o-phenyl-enediamine derivative.