Topic
Substituent
About: Substituent is a research topic. Over the lifetime, 42877 publications have been published within this topic receiving 516716 citations. The topic is also known as: side chain & side group.
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TL;DR: The finding that transferrin does not bind Fe3+ at the specific metal binding sites in the absence of carbonate and synergistic anions emphasizes the fundamental importance of the anion binding site to the chemistry of Fe3-transferrin-CO32-.
268 citations
268 citations
04 Apr 2007
266 citations
TL;DR: The mechanism and compounds for the colorimetric identification of cyanide can lead to the development of practical strategies for the convenient determination of this toxic anion in aqueous environments.
Abstract: We have designed two heterocyclic compounds for the colorimetric detection of cyanide. The skeleton of both molecules fuses a benzooxazine ring to an indoline fragment and can be assembled efficiently in three synthetic steps starting from commercial precursors. The two compounds differ in the nature of the substituent on the carbon atom at the junction of the fused heterocycles, which can be either a methyl or a phenyl group. In the presence of cyanide, both molecules are converted quantitatively into cyanoamines with the concomitant appearance of an intense band in the visible region of the absorption spectrum. The developing absorption is a result of the opening of the benzooxazine ring with the formation of a 4-nitrophenylazophenolate chromophore. Nuclear magnetic resonance spectroscopy and X-ray crystallographic analyses demonstrate that the covalent attachment of a cyanide anion to the indoline fragment is responsible for these transformations. The chromogenic process is particularly fast for the me...
265 citations
01 Jan 1976
264 citations