Pyrrolo[3,2-b]pyrroles-From Unprecedented Solvatofluorochromism to Two-Photon Absorption.
Pyrrolo[3,2-b]pyrroles-From Unprecedented Solvatofluorochromism to Two-Photon Absorption.
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DOI：
10.1002/chem.201502762
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发表时间：
2015-12-07
期刊：
影响因子：
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通讯作者：
Gryko DT
中科院分区：
文献类型：
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作者：
Friese DH;Mikhaylov A;Krzeszewski M;Poronik YM;Rebane A;Ruud K;Gryko DT
对具有高富电子杂环核的一系列四极性分子吡咯[3,2-b]吡咯的双光子吸收特性进行了实验和理论结合研究。与量子化学计算结果一致，在波长650 ~ 700 nm处观察到较大的双光子吸收（2PA）截面值σ2PA ~ 102 ~ 103 GM (1GM = 1050 cm4 s photon−1)，对应于允许双光子跃迁而禁止单光子跃迁。计算还预测，通过去除两个n取代基，增加了分子的平面度，导致σ2PA值进一步增加。令人惊讶的是，最具四极性的吡咯[3,2-b]衍生物在2位和5位上含有两个4-硝基苯取代基，表现出很强的溶剂化荧光致色效应，在环己烷中荧光量子产率高达0.96，而在DMSO中荧光消失。
A combined experimental and theoretical study of the two-photon absorption properties of a series of quadrupolar molecules possessing a highly electron-rich heterocyclic core, pyrrolo[3,2-b]pyrrole is presented. In agreement with quantum-chemical calculations, we observe large two-photon absorption (2PA) cross-section values, σ2PA ~ 102–103 GM (1GM = 1050 cm4 s photon−1) at wavelengths 650–700 nm, corresponding to the 2-photon allowed but 1-photon forbidden transitions. The calculations also predict that increased planarity of this molecule via removal of two N-substituents leads to further increase in the σ2PA values. Surprisingly, the most quadrupolar pyrrolo[3,2-b]pyrrole derivative bearing two 4-nitrophenyl substituents at positions 2 and 5 demonstrates very strong solvatofluorochromic effect, with the fluorescence quantum yield as high as 0.96 in cyclohexane, while the fluorescence vanishes in DMSO.