Schiff Base


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Schiff base

[′shif ‚bās]
(organic chemistry)
RR′C=NR″ Any of a class of derivatives of the condensation of aldehydes or ketones with primary amines; colorless crystals, weakly basic; hydrolyzed by water and strong acids to form carbonyl compounds and amines; used as chemical intermediates and perfume bases, in dyes and rubber accelerators, and in liquid crystals for electronics.

Schiff Base

 

any one of a class of organic compounds with the general formula RR′C═NR″, where R and R′ represent hydrogen, an alkyl, or an aryl and R″ is an alkyl or aryl; in the latter case, Schiff bases are also called anils.

Schiff bases are crystalline or oily substances that are insoluble in water and soluble in organic solvents. They are weak bases, forming salts with acids in an anhydrous medium; in aqueous acid solutions they undergo hydrolysis to yield an amine and aldehyde. The majority of Schiff bases are stable in alkaline solutions. Schiff bases undergo hydrogenation to give secondary amines (RR′CH—NHR″) and add on many compounds containing mobile hydrogen, such as (β-dicarbonyl compounds, ketones, and imines. They are produced mainly by the condensation of aldehydes or ketones with primary amines.

The reaction was first completed by H. Schiff in 1864 (hence the name of the compounds). Schiff bases are valuable intermediate products of organic synthesis, for example, in the preparation of secondary amines and various heterocyclic compounds. The Schiff bases known as azomethine dyes are used for dyeing acetate and synthetic fibers; they are also used in color photography to reduce the photosensitivity of photographic emulsions.

References in periodicals archive ?
Khan, New Antimicrobial Agents: The Synthesis of Schiff Base Polymers Containing Transition Metals and their Characterization and Applications, J.
In this work synthesis and application of a new Schiff base ligand (L) (Figure 1) as modifier of an octadecyl silica membrane disk for preconcentration and determination of copper and cadmium in various media by flame atomic absorption spectrometry have been reported.
The peaks appeared in the lower wavelength zones might be due to aromatic nature of Schiff base ligand and the peaks in the higher wavelength could be due to the presence of C=N or C=O or a combination of them.
Two novel homologous polyphosphoesters containing anthracene- and furan-derived aminophosphonate moieties, poly[oxyethylene(aminophosphonate-co-H-phosphonate)]s P-12 and P-13, were synthesized through an addition of poly (oxyethylene H-phosphonate) 1 to the Schiff base 9-anthrylidene-furfurylamine S-2.
Li, "An unexpected cobalt(III) complex containing a Schiff base ligand: Synthesis, crystal structure, spectroscopic behavior, electrochemical property and SOD-like activity," Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, vol.
The study of infrared spectra of the furan Schiff base H-MFMAQ comparing to their metal complexes (1-7) (Table 4; Figure 3) foremost revealed that the ligand is tetradentately coordinated to the metal ions.
Metal-free methods in the synthesis of macrocyclic Schiff bases. Chem Rev 2007; 107: 46-79, doi: 10.1021/cr0683616.
aureus suggests that the linked hydrazine might significantly improve the antibacterial activity of N,N-disubstituted Schiff bases. Similarly, the phenyl group was inserted to form the salicylaldehyde-o-phenylenediamine Schiff base (compound 1c) that exhibited a potent inhibition on the growth of leukemia cells, which may play an essential role in this selective anticancer activity.