o-Fluoroazobenzenes as Readily Synthesized Photoswitches Offering Nearly Quantitative Two-Way Isomerization with Visible Light
o-Fluoroazobenzenes as Readily Synthesized Photoswitches Offering Nearly Quantitative Two-Way Isomerization with Visible Light
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DOI：
10.1021/ja310323y
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发表时间：
2012-12-26
影响因子：
15
通讯作者：
Hecht, Stefan
中科院分区：
文献类型：
--
作者：
Bleger, David;Schwarz, Jutta;Hecht, Stefan
用邻氟原子官能化的偶氮苯具有较低的 Z 异构体 n 轨道能量，导致 E 和 Z 异构体的 n -> pi* 吸收带分离。引入对位取代基可以进一步调节邻氟偶氮苯的吸收光谱。特别是，吸电子酯基团导致 n ->pi* 跃迁间隔 50 nm。因此，绿光和蓝光可分别用于诱导 E -> Z 和 Z -> E 异构化。邻氟偶氮苯支架很容易合成，并且可以通过其芳基末端插入到更大的结构中。这些新型偶氮苯衍生物可以以两种方式进行转换，具有高光转化率，并且它们的 Z 异构体表现出非常长的热半衰期。
Azobenzene fimctionalized with ortho-fluorine atoms has a lower energy of the n-orbital of the Z-isomer, resulting in a separation of the E and Z isomers' n ->pi* absorption bands. Introducing para-substituents allows for further tuning of the absorption spectra of o-fluoroazobenzenes. In particular, electron-withdrawing ester groups give rise to a 50 nm separation of the n ->pi* transitions. Green and blue light can therefore be used to induce E -> Z and Z -> E isomerizations, respectively. The o-fluoroazobenzene scaffold is readily synthesized and can be inserted into larger structures via its aryl termini. These new azobenzene derivatives can be switched in both ways with high photoconversions, and their Z-isomers display a remarkably long thermal half-life.