(E)-N'-(2-Hydr-oxy-4-methoxy-benzyl-idene)isonicotinohydrazide monohydrate
Acta Crystallographica. Section E, Structure Reports Online
|January 5, 2011
Summary
This study details the synthesis and structural analysis of a novel Schiff base compound. The research reveals its non-planar molecular structure and intricate hydrogen bonding network in the crystal lattice.
Area of Science:
- Organic Chemistry
- Crystallography
Background:
- Schiff bases are versatile organic compounds with diverse applications.
- Understanding the structure-property relationships of Schiff bases is crucial for their development.
Purpose of the Study:
- To synthesize a novel Schiff base from 4-methoxy-salicylaldehyde and isonicotinohydrazide.
- To characterize the synthesized compound's molecular and crystal structure.
- To investigate the hydrogen bonding interactions within the crystal.
Main Methods:
- Chemical synthesis involving the reaction of 4-methoxy-salicylaldehyde and isonicotinohydrazide in ethanol.
- Structural analysis of the resulting Schiff base compound.
- X-ray crystallography to determine the molecular and crystal structure, including dihedral angles and hydrogen bonding.
Main Results:
- The Schiff base compound, C(14)H(13)N(3)O(3)·H(2)O, was successfully synthesized.
- The molecule exhibits a non-planar structure with an E configuration around the methylidene unit.
- A dihedral angle of 36.8(2)° was observed between the benzene and pyridine rings.
- Intramolecular O-H⋯N and intermolecular O-H⋯O, O-H⋯N, N-H⋯O hydrogen bonds were identified, forming layered structures.
Conclusions:
- The synthesized Schiff base possesses a unique non-planar geometry.
- The study elucidates the significant role of hydrogen bonding in stabilizing the crystal structure.
- This structural insight is valuable for designing related compounds with specific properties.
Related Concept Videos
01:11Nomenclature of Carboxylic Acid Derivatives: Amides and Nitriles
Naming Amides
The IUPAC and common names of amides are derived from the parent carboxylic acid, by replacing the suffix “oic acid” and “ic acid,” respectively, with “amide.” In the following example, the IUPAC name ethanamide is derived from ethanoic acid, and the common name, acetamide, is obtained from acetic acid.
The IUPAC and common names of amides are derived from the parent carboxylic acid, by replacing the suffix “oic acid” and “ic acid,” respectively, with “amide.” In the following example, the IUPAC name ethanamide is derived from ethanoic acid, and the common name, acetamide, is obtained from acetic acid.
01:19Diazonium 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.
01:19Nitrosation of Enols
The nitrosation reaction is one of the methods of preparing 1,2-diketones. The enol tautomer of the starting ketone reacts with sodium nitrite in hydrochloric acid, generating the 1,2-diketone after hydrolysis.
01:371° 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.
01:261° 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...
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...
01:32Aldehydes and Ketones with HCN: Cyanohydrin Formation Overview
Cyanohydrins are compounds that contain –CN and –OH groups on the same carbon atom. They are formed by the nucleophilic addition of the cyanide ions to the carbonyl group. Cyanide ions are highly basic and nucleophilic and can be generated from HCN under aqueous conditions. However, since HCN is a weak acid, the number of cyanide ions generated is very small. Hence, a small amount of base or KCN/NaCN is added to HCN to increase the concentration of the cyanide ions in the reaction mixture.