Ylidenemalononitrile Enamines as Fluorescent “Turn-On” Indicators for Primary Amines

Ylidenemalononitrile enamines undergo rapid amine exchange followed by a cyclization with primary amines to yield fluorescent products with emission intensities as high as 900 times greater than the starting materials. After identifying the fluorescent species by X-ray crystallography, we demonstrate that the rate of amine exchange is substrate dependent and that by simple structural variation the fluorescence can be tuned over the entire visible spectrum. We further demonstrate their potential application in biomolecule labeling.

亚烷基丙二腈烯胺（Ylidenemalononitrile enamines）可快速发生胺交换反应，随后与伯胺发生环化反应，生成荧光产物，其荧光发射强度最高可达起始原料的900倍。通过X射线晶体学（X-ray crystallography）鉴定该荧光产物的结构后，我们证实胺交换反应的速率具有底物依赖性，且仅通过简单的结构修饰，即可将荧光发射波长调控至整个可见光光谱范围内。我们进一步验证了该类化合物在生物分子标记领域的应用潜力。