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Related Concept Videos

Aryldiazonium Salts to Azo Dyes: Diazo Coupling01:11

Aryldiazonium Salts to Azo Dyes: Diazo Coupling

The reaction of weakly electrophilic aryldiazonium (also called arenediazonium) salts with highly activated aromatic compounds leads to the formation of products with an —N=N— link, called an azo linkage. This reaction, presented in Figure 1, is known as diazo coupling and occurs without the loss of the nitrogen atoms of the aryldiazonium salt. Highly activated aromatic compounds such as phenols or arylamines favor the diazo coupling reaction. The coupling generally occurs at the para position.
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.
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.
Carboxylic Acids to Methylesters: Alkylation using Diazomethane01:33

Carboxylic Acids to Methylesters: Alkylation using Diazomethane

Carboxylic acids react with diazomethane in an ether solvent via alkylation at the carboxylate oxygen atom to give methyl esters of the corresponding acid with excellent yields.
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...

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Related Experiment Video

Updated: Jun 1, 2026

Continuous Flow Chemistry: Reaction of Diphenyldiazomethane with p-Nitrobenzoic Acid
07:06

Continuous Flow Chemistry: Reaction of Diphenyldiazomethane with p-Nitrobenzoic Acid

Published on: November 15, 2017

Piperazinediium dioxamate.

S Murugavel, R Selvakumar, S Govindarajan

    Acta Crystallographica. Section E, Structure Reports Online
    |May 18, 2011
    PubMed
    Summary
    This summary is machine-generated.

    This study details the crystal structure of a compound containing piperazinium cations and dioxamate anions. Hydrogen bonds between these ions stabilize the overall crystal structure.

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    Published on: November 15, 2017

    Synthesis of pH Dependent Pyrazole, Imidazole, and Isoindolone Dipyrrinone Fluorophores using a Claisen-Schmidt Condensation Approach
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    Preparation of Stable Bicyclic Aziridinium Ions and Their Ring-Opening for the Synthesis of Azaheterocycles
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    Preparation of Stable Bicyclic Aziridinium Ions and Their Ring-Opening for the Synthesis of Azaheterocycles

    Published on: August 22, 2018

    Area of Science:

    • Crystallography
    • Supramolecular Chemistry
    • Organic Chemistry

    Background:

    • Piperazine derivatives are important in various chemical applications.
    • Understanding hydrogen bonding networks is crucial for crystal engineering.
    • Dioxamate anions offer unique coordination and hydrogen bonding capabilities.

    Purpose of the Study:

    • To elucidate the crystal structure of the title compound.
    • To characterize the interactions between piperazinium cations and dioxamate anions.
    • To investigate the role of hydrogen bonding in stabilizing the crystal lattice.

    Main Methods:

    • Single-crystal X-ray diffraction was employed to determine the crystal structure.
    • Analysis of bond lengths, angles, and intermolecular interactions.
    • Conformational analysis of the piperazinium dication.

    Main Results:

    • The crystal structure consists of doubly protonated piperazinium cations and dioxamate anions.
    • The piperazinium dication adopts a chair conformation.
    • A network of N-H⋯O hydrogen bonds stabilizes the crystal structure, involving both cation-anion and anion-anion interactions.

    Conclusions:

    • The crystal structure provides insight into the packing and interactions of piperazinium and dioxamate ions.
    • Hydrogen bonding plays a critical role in the self-assembly and stability of this crystalline material.
    • This study contributes to the understanding of supramolecular assembly in organic salts.