Nitropyrene Photoprobes: Making Them, and What Are They Good for?
Nitropyrene Photoprobes: Making Them, and What Are They Good for?
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DOI：
10.1002/ejoc.201501339
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发表时间：
2016-01-01
影响因子：
2.8
通讯作者：
Vullev, Valentine I.
中科院分区：
文献类型：
--
作者：
Espinoza, Eli M.;Xia, Bing;Vullev, Valentine I.
芘类化合物是应用最广泛的有机荧光光探针之一。其中许多是用于空穴注入的光敏剂。然而，吡喃主要是紫外线吸收剂，限制了它们在光子应用中的用途。芘的硝化作用使其吸收转移到可见光区。相反，已经为共价标记衍生化的芘的硝化反应会产生难以分离的异构体混合物。我们提出了一种获得异构化纯硝基吡喃的可靠方法。核磁共振分析提供了区域异构体和双取代的硝基吡喃的结构的明确归属。添加的取代基对硝基吡喃的电子性质影响可以忽略不计。光激发的硝基吡喃具有高效的三重态形成能力，使其成为三重态敏化剂和光氧化剂的理想选择。因此，简单可靠地制备二取代的硝基吡喃为探索它们的电子和光子用途提供了场所。
Pyrene derivatives are among the most widely used organic fluorescent photoprobes. Many of them are photosensitizers for hole injection. Pyrenes, however, are mostly UV absorbers, limiting their utility for photonic applications. Nitration of pyrene shifts its absorption to the visible region. Conversely, nitration of pyrene that is already derivatized for covalent labeling, produces mixtures of isomers that are challenging to separate. We present a robust procedure for attaining isomerically pure nitropyrenes. NMR analysis provides unequivocal assignments of the regioisomers and of the structures of the disubstituted nitropyrenes. The added substituents negligibly affect the electronic properties of the nitropyrenes. Photoexcited nitropyrenes undergo efficient triplet formation, making them an attractive choice for triplet sensitizers and photooxidants. Hence, facile and reliable preparation of disubstituted nitropyrenes provides venues for exploring their electronic and photonic utility.