Conjugated Polymers That Respond to Oxidation with Increased Emission
Conjugated Polymers That Respond to Oxidation with Increased Emission
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DOI：
10.1021/ja1019063
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发表时间：
2010-06-09
影响因子：
15
通讯作者：
Swager, Timothy M.
中科院分区：
文献类型：
--
作者：
Dane, Eric L.;King, Sarah B.;Swager, Timothy M.
含硫醚的聚（对亚苯基-乙炔基）（PPE）共聚物在溶液中暴露于氧化剂时，由于硫醚取代基选择性转化为亚砜和砜，显示出强烈的荧光开启响应。我们提出，氧化时荧光量子产率（Phi（F））的增加是荧光速率（k（F））增加的结果，这是由于氧化材料中前线分子轨道的空间重叠更大，以及荧光寿命（tau（F））的增加，由于非辐射衰减速率的降低。与已建立的文献相反，所报道的亚砜并不总是充当荧光猝灭剂。氧化伴随着聚合物的吸收和发射的光谱变化，当氧化导致共聚物获得供体-受体相互作用时，这是显著的。氧化的聚合物在固态下具有高荧光量子产率，其中一些具有增加的光稳定性。在氧化催化剂的存在下，在有机溶剂中对过氧化氢的开启荧光响应表明含硫醚的材料用于氧化剂传感的潜力。报道的聚合物显示出作为新材料在光稳定性重要的应用中的前景，其中期望在可见光谱范围内发射的可调谐性，并且其中有效发射是一个优势。
Thioether-containing poly(para-phenylene-ethynylene) (PPE) copolymers show a strong fluorescence turn-on response when exposed to oxidants in solution as a result of the selective conversion of thioether substituents into sulfoxides and sulfones. We propose that the increase in fluorescence quantum yield (Phi(F)) upon oxidation is the result of both an increase in the rate of fluorescence (k(F)), as a result of greater spatial overlap of the frontier molecular orbitals in the oxidized materials, and an increase in the fluorescence lifetime (tau(F)), due to a decrease in the rate of nonradiative decay. Contrary to established literature, the reported sulfoxides do not always act as fluorescence quenchers. The oxidation is accompanied by spectral changes in the absorption and emission of the polymers, which are dramatic when oxidation causes the copolymer to acquire a donor-acceptor interaction. The oxidized polymers have high fluorescence quantum yields in the solid state, with some having increased photostability. A turn-on fluorescence response to hydrogen peroxide in organic solvents in the presence of an oxidation catalyst indicates the potential of thioether-containing materials for oxidant sensing. The reported polymers show promise as new materials in applications where photostability is important, where tunability of emission across the visible spectrum is desired, and where efficient emission is an advantage.