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.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.

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.

The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.
References in periodicals archive ?
Colotin, Poly(Schiff base)s containing 1, 1'-binaphthyl moieties: synthesis and characterization, Macromol Chem.
As the effort towards the synthesis of metal based therapeutic agents, here we report the preparation and characterization of new complex derivative of Schiff base ligand: (E)-2-((3-(bezyloxypyridinylimino) methyl)-4-bromophenol (HL).
The promyelocytic and T-cell leukemic cell lines (HL-60 and SKW-3 cells, respectively) were generally more sensitive to the a-aminophosphonates A-3 and A-4 than to the Schiff bases, whereas the latter exerted substantially stronger cytotoxic effects against the B-cell lymphoma cell line (REH).
The phenolic -OH stretching frequency at 1267 [cm.sup.-1] found in the spectrum of the Schiff base was absent in the spectra of metal complexes and might be due to the coordination of the phenol oxygen atom involved in complexation as C-O-M at ~1224[cm.sup.-1] [46].
Recently, Al-Shemary and Zaidan [5] reported the successful synthesis and characterization of a new tetradented Schiff base ligand known as 2,2'(1E,1'E)-(ethane-1,2-diylbis (azan-1-yl-1-ylidene))bis(phenylmethan-1-yl-1-ylidene)dibenzoic acid (EDA2Bb) and its [Cu.sup.II], [Ni.sup.II], [Mn.sup.II], [Co.sup.II], and [Hg.sup.II] complexes.
With due regard to the secondary lipid peroxidation products, the level of triene conjugates and Schiff bases remains approximately constant with a pronounced minimum at [N.sub.2][M.sub.1] regardless the histological type of a tumor.
In conclusion, we successfully obtained two new Co(II)-coordination compounds (1 and 2) by employing two different flexible Schiff base ligands.
Synthesis Procedure for N,N-Disubstituted Schiff Bases. Compounds 1a, 1b, and 1c were synthesized according to the report of Przybylski et al.
Schiff bases forms an important class of organic compounds and are widely studied for various biological applications over the decades [1-3].