Otto-Diels Institut für Organische Chemie, Christian-Albrechts-Universität zu Kiel, Otto-Hahn-Platz 4, 24418 Kiel, Germany.
Beilstein J Org Chem. 2013;9:1-7. doi: 10.3762/bjoc.9.1. Epub 2013 Jan 2.
Azobenzenes are robust, reliable, and easy to synthesize photochromic switches. However, their high conformational flexibility is a disadvantage in machine-like applications. The almost free rotation of the phenyl groups can be restricted by bridging two ortho positions with a CH(2)CH(2) group, as realized in the dihydrodibenzo diazocine framework. We present the synthesis and properties of 3,3'-amino- and 3,3'-acetamido substituted diazocines. Upon irradiation with light of 405 and 530 nm they isomerize from the cis to the trans configuration and back, and thereby perform a pincer-like motion. In the thermodynamically more stable cis isomer the lone pairs of the amino nitrogen atoms point towards each other, and in the trans form they point in opposite directions. The distance between the amino nitrogen atoms changes between 8 Å (cis) and 11 Å (trans isomer).
偶氮苯是坚固、可靠且易于合成的光致变色开关。然而，其高构象灵活性在类机器应用中是一个缺点。通过用 CH(2)CH(2)基团桥接两个邻位位置，可以限制苯基的几乎自由旋转，这在二氢二苯并氮杂环辛烷骨架中得到了实现。我们介绍了 3,3'-氨基和 3,3'-乙酰胺基取代的重氮化合物的合成和性质。用 405nm 和 530nm 的光照射时，它们从顺式向反式构型异构化，然后再返回，从而进行类似钳子的运动。在热力学上更稳定的顺式异构体中，氨基氮原子的孤对电子彼此指向对方，而在反式异构体中则指向相反的方向。氨基氮原子之间的距离在 8Å（顺式）和 11Å（反式异构体）之间变化。
