Comparative studies on electronic spectra and redox behaviors of isomeric benzo[1,2-b:4,5-b']difurans and benzo[1,2-b:5,4-b']difurans.
Comparative studies on electronic spectra and redox behaviors of isomeric benzo[1,2-b:4,5-b']difurans and benzo[1,2-b:5,4-b']difurans.
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异构苯并[1,2-b:4,5-b]二呋喃和苯并[1,2-b:5,4-b]二呋喃的电子光谱和氧化还原行为的比较研究。
DOI：
10.1021/jp900898e
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发表时间：
2009
影响因子：
2.9
通讯作者：
Kengo Suzuki
中科院分区：
文献类型：
--
作者：
N. Hayashi;Y. Saito;H. Higuchi;Kengo Suzuki
研究了异构苯并[1,2-b:4,5-b']二呋喃 (1a) 和苯并[1,2-b:5,4-b']二呋喃 (2a) 及其 α,α'-二正丁基（1b 和 2b）和双（3,5-二己氧基苯基）衍生物（1c 和 2c）的电子吸收/发射光谱、绝对荧光量子产率和氧化电位。最长波长吸收最大值在1a和2a之间以及1b和2b之间非常接近；然而，由于后者的交叉共轭，1c 的最大吸收与 2c 相比显着红移。与相关化合物不同，顺式 (1a-c) 和反式 (2a-c) 异构体的荧光量子产率几乎相同。另一方面，顺式异构体的氧化电位显着低于反式异构体。分子轨道计算表明，这可能是苯并二呋喃的特征，因为 [1,2-b:4,5-b'] 和 [1,2-b:5,4-b'] 异构体的 HOMO 能级据估计在其他苯并二硫族元素酚中几乎相同。
Electronic absorption/emission spectra, absolute fluorescence quantum yields, and oxidation potentials of isomeric benzo[1,2-b:4,5-b']difurans (1a) and benzo[1,2-b:5,4-b']difurans (2a) along with their alpha,alpha'-di-n-butyl (1b and 2b) and bis(3,5-dihexyloxyphenyl) derivatives (1c and 2c) were studied. The longest wavelength absorption maxima were very close between 1a and 2a and between 1b and 2b; however, the maximum absorption of 1c was significantly red-shifted compared to that of 2c, due to cross-conjugation in the latter. Unlike related compounds, the fluorescence quantum yields of syn (1a-c) and anti (2a-c) isomers were virtually identical. On the other hand, the oxidation potentials of the syn isomers were significantly lower than those of the anti isomers. Molecular orbital calculations revealed that this is likely to be characteristic of benzodifurans, because HOMO energy levels of the [1,2-b:4,5-b'] and [1,2-b:5,4-b'] isomers were estimated to be virtually identical in the other benzodichalcogenophenes.