Chromogenic oxazines for cyanide detection

Massimiliano Tomasulo, Salvatore Sortino, Andrew J P White, Francisco Raymo

Research output: Contribution to journalArticle

248 Citations (Scopus)

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 union to the indoline fragment is responsible for these transformations. The chromogenic process is particularly fast for the methyl-substituted oxaxine and can be exploited to detect micromolar concentrations of cyanide in water. Furthermore, the colorimetric response of this compound to cyanide does not suffer the interference of the halide anions, which instead are known to complicate the detection of cyanide in conventional sensing protocols. Thus, our mechanism and compounds for the colorimetric identification of cyanide can lead to the development of practical strategies for the convenient determination of this toxic union in aqueous environments.

Original languageEnglish
Pages (from-to)744-753
Number of pages10
JournalJournal of Organic Chemistry
Volume71
Issue number2
DOIs
StatePublished - Jan 20 2006

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Oxazines
Chromogenics
Cyanides
Heterocyclic Compounds
Molecules
Poisons
Electric fuses
Chromophores
Nuclear magnetic resonance spectroscopy
Anions
Absorption spectra
Carbon
X rays
Atoms
Water

ASJC Scopus subject areas

  • Organic Chemistry

Cite this

Chromogenic oxazines for cyanide detection. / Tomasulo, Massimiliano; Sortino, Salvatore; White, Andrew J P; Raymo, Francisco.

In: Journal of Organic Chemistry, Vol. 71, No. 2, 20.01.2006, p. 744-753.

Research output: Contribution to journalArticle

Tomasulo, M, Sortino, S, White, AJP & Raymo, F 2006, 'Chromogenic oxazines for cyanide detection', Journal of Organic Chemistry, vol. 71, no. 2, pp. 744-753. https://doi.org/10.1021/jo052096r
Tomasulo, Massimiliano ; Sortino, Salvatore ; White, Andrew J P ; Raymo, Francisco. / Chromogenic oxazines for cyanide detection. In: Journal of Organic Chemistry. 2006 ; Vol. 71, No. 2. pp. 744-753.
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