Niko Yosuke, Sasaki Shunsuke, Kawauchi Susumu, Tokumaru Katsumi, Konishi Gen-Ichi
Department of Organic and Polymeric Materials, Tokyo Institute of Technology, O-okayama, Tokyo 152-8552 (Japan), Fax: (+81) 3-5734-2321.
Chem Asian J. 2014 Jul;9(7):1797-807. doi: 10.1002/asia.201402088. Epub 2014 May 6.
We designed, synthesized, and evaluated environmentally responsive solvatochromic fluorescent dyes by incorporating weak push-pull moieties. The quantum yields of the push (alkyl)-pull (formyl) pyrene dyes were dramatically enhanced by the introduction of alkyl groups into formylpyrene (1-formylpyrene: Φ(F) =0.10; 3,6,8-tri-n-butyl-1-formylpyrene: Φ(F) =0.90; in MeOH). The new dyes exhibited unique sensitivity to solvent polarity and hydrogen-bond donor ability, and specific fluorescence turn-on/off properties (e.g., 3,6,8-tri-n-butyl-1-formylpyrene: Φ(F) =0.004, 0.80, 0.37, and 0.90 in hexane, chloroform, DMSO, and MeOH, respectively). Here, the alkyl groups act as weak donors to suppress intersystem crossing by destabilizing the HOMOs of 1-formylpyrene while maintaining weak intramolecular charge-transfer properties. By using alkyl groups as weak donors, environmentally responsive, and in particular, pH-responsive fluorescent materials may be developed in the future.
我们通过引入弱推拉基团设计、合成并评估了对环境响应的溶剂化变色荧光染料。通过将烷基引入甲酰基芘中，推电子（烷基）-拉电子（甲酰基）芘染料的量子产率显著提高（1-甲酰基芘：Φ(F)=0.10；3,6,8-三正丁基-1-甲酰基芘：Φ(F)=0.90；在甲醇中）。这些新染料对溶剂极性和氢键给体能力表现出独特的敏感性，以及特定的荧光开启/关闭特性（例如，3,6,8-三正丁基-1-甲酰基芘在己烷、氯仿、二甲基亚砜和甲醇中的Φ(F)分别为0.004、0.80、0.37和0.90）。在这里，烷基作为弱供体，通过使1-甲酰基芘的最高占据分子轨道不稳定来抑制系间窜越，同时保持弱的分子内电荷转移性质。通过使用烷基作为弱供体，未来可能开发出对环境响应，特别是对pH响应的荧光材料。
