Substituent effects on fluorescent properties of imidazo[1,2-α] pyridine-based compounds
Substituent effects on fluorescent properties of imidazo[1,2-α] pyridine-based compounds
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DOI：
10.1246/bcsj.72.1327
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发表时间：
1999-06-01
影响因子：
4
通讯作者：
Araki, K
中科院分区：
文献类型：
--
作者：
Tomoda, H;Hirano, T;Araki, K
为了寻找新型的荧光有机化合物，合成了20个咪唑并[1，2-a]吡啶（1）衍生物，并对其荧光性质进行了研究。虽然母体化合物1（λ（f1）= 370.5nm，Phi = 0.57，在乙醇中）在环境温度下为液态，2-苯基咪唑并[1，2-a]吡啶（5）、2-（2-萘基）咪唑并[1，2-a]吡啶（16）、7-甲基咪唑并[1，2-a]吡啶（3）、7-甲基-2-苯基咪唑并[1，2-a]吡啶（12）和7-甲基-2-苯基咪唑并[1，2-a]吡啶（14）。发现（2-萘基）咪唑并[1，2-a]吡啶（17）得到热稳定的固体化合物（mp 55-19 ℃），而对母体化合物的荧光性质没有太大影响（λ（f1）= 374-381 nm，Phi = 0.50-0.78，在乙醇中）。在4 ′-取代的2-苯基衍生物中，发现强给电子氨基和二甲氨基的引入（2-（4-氨基苯基）咪唑并[1，2-a]吡啶（7）和2- [4-（三氟甲基）苯基]咪唑并[1，2-a]吡啶（二甲氨基）苯基]咪唑并[I，Za]吡啶（8）使其荧光明显红移（λ（f1）分别为445和446 nm，在乙醇中），从而提供了调节IP衍生物的荧光颜色的方法。7和8的荧光红移归因于激发态分子内电荷转移态的贡献。
In order to search for novel fluorescent organic compounds, 20 derivatives of imidazo[1,2-a]pyridine (1) were synthesized, and their fluorescent properties were studied. Though the parent compound 1 (lambda(fl) = 370.5 nm, Phi = 0.57 in ethanol) was in the liquid state at ambient temperature, 2-phenylimidazo[1,2-a]pyridine (5), 2-(2-naphthyl)imidazo[1,2-a]pyridine (16), 7-methylimidazo[1,Za]pyridine (3), 7-methyl-2-phenylimidazo[ 1,2-a]pyridine (12), and 7-methyl-2-(2-naphthyl)imidazo[ 1,2-a]pyridine (17) were found to give thermally stable solid compounds (mp 55-19 degrees OC) without much affecting the fluorescent properties of the parent compound (lambda(fl) = 374-381 nm, Phi = 0.50-0.78 in ethanol). Among the 4'-substituted 2-phenyl derivatives, it was found that the introduction of the strong electron-donating amino and dimethylamino groups (2- (4-aminophenyl)imidazo [1,2-a]pyridine (7) and 2- [4-(dimethylamino)phenyl] imidazo[I,Za]pyridine (8), respectively) caused marked red shift of their fluorescence (lambda(fl) = 445 and 446 nm, respectively, in ethanol), thus providing the way for tuning the fluorescence color of the IP derivatives. The observed red shift of the fluorescence of 7 and 8 was ascribed to the contribution of the excited intramolecular charge transfer state.