Chromogenic oxazines for cyanide detection
Chromogenic oxazines for cyanide detection
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DOI：
10.1021/jo052096r
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发表时间：
2006-01-20
影响因子：
3.6
通讯作者：
Raymo, FM
中科院分区：
文献类型：
--
作者：
Tomasulo, M;Sortino, S;Raymo, FM
我们设计了两种用于氰化物比色检测的杂环化合物。这两种分子的骨架融合了一个苯并恶嗪环和一个吲哚片段，并且可以从商业前体开始在三个合成步骤中有效地组装。这两种化合物的不同之处在于稠合杂环连接处碳原子上取代基的性质，其可以是甲基或苯基。在氰化物的存在下，这两种分子定量转化为氰胺，同时在吸收光谱的可见光区出现一个强带。显色吸收是苯并恶嗪环打开形成4-硝基苯偶氮酚发色团的结果。核磁共振光谱和X-射线晶体学分析表明，共价连接的氰阴离子的吲哚片段是负责这些转换。显色过程是特别快的甲基取代的恶嗪，并可用于检测微摩尔浓度的氰化物在水中。此外，该化合物对氰化物的比色响应不会受到卤素阴离子的干扰，而已知卤素阴离子会使常规传感方案中氰化物的检测复杂化。因此，我们的机制和化合物的氰化物的比色鉴定可以导致实用的策略，方便地测定这种有毒阴离子在水环境中的发展。
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-nitrophenyl azophenolate 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 methylsubstituted oxazine 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 anion in aqueous environments.