Colorimetric and fluorimetric detection of cysteine: Unexpected Michael addition-elimination reaction

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• 作者：Hao-Ran Qu^a ; Zi-You Zhang^a ; Nan Wang^a ; Qian Sun^a ; Shan-Shan Liu^a ; Wei-Bing Zhang^a ; Jun-Hong Qian^a ; ^b ; ^{junhongqian@ecust.edu.cn" class="auth_mail" title="E-mail the corresponding author}
• 关键词：Michael addition ; Sulfur-containing compounds ; Cysteine ; Fluorescent probe
• 刊名：Chinese Chemical Letters
• 出版年：2015
• 出版时间：October 2015
• 年：2015
• 卷：26
• 期：10
• 页码：1249-1254
• 全文大小：951 K

文摘

The synthesis of three isomers based on Michael addition mechanism for the detection of sulfur-containing species in aqueous solution is described. These compounds are constructed by conjugating an enone to a coumarin fluorophore. A substituted-phenyl (o, m, or p-) was appended at the carbonyl carbon to adjust the reactivity. The experimental results showed that (E)-7-(diethylamino)-3-(3-(3-hydroxyphenyl)-3-oxoprop-1-en-1-yl)-2H-chromen-2-one (m-QPS) and (E)-7-(diethylamino)-3-(3-(4-hydroxyphenyl)-3-oxoprop-1-en-1-yl)-2H-chromen-2-one (p-QPS) barely react with sulfur-containing nucleophiles, while (E)-7-(diethylamino)-3-(3-(2-hydroxyphenyl)-3-oxoprop-1-en-1-yl)-2H-chromen-2-one (o-QPS) exhibited a fast response toward sulfite, sulfide and thiols in DMSO/phosphate buffer (2:1). The above results are probably due to the intramolecular H-bonding activated Michael addition. More interestingly, cysteine triggered unusual photophysical responses of o-QPS: the original absorption (488 nm) and emission peaks (573 nm) underwent significant blue shifts initially and then recovered, which might be caused by the Michael addition and elimination reaction, respectively.