Rananaware Anushri, Samanta Mousumi, Bhosale Rajesh S, Al Kobaisi Mohammad, Roy Biswajit, Bheemireddy Varun, Bhosale Sidhanath V, Bandyopadhyay Subhajit, Bhosale Sheshanath V
School of Applied Sciences, RMIT University, GPO Box 2476, Melbourne, VIC-3001, Australia.
Department of Chemical Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur, Nadia WB 741246, India.
Sci Rep. 2016 Mar 8;6:22928. doi: 10.1038/srep22928.
The discovery of photoswitchable azobenzene-systems that undergo trans-to-cis photoisomerisation was a milestone in supramolecular chemistry. Such photoswitches have possible applications in data storage, stimuli responsive delivery systems, and molecular machines due to fast and selective switching. However, the light induced cis isomer of azobenzene is rather unstable and reverts thermally and photochemically to the thermodynamically stable trans configuration. We report, for the first time, controlled photoswitching of an azo-naphthalenediimide (azo-NDI) which can be achieved upon binding of fluoride ions through anion-π interaction. This NDI-F-NDI "sandwich" stabilises the cis configuration through the generation of an NDI(•-) radical anion, and a dianionic, NDI(2-) species that becomes unusually stable in the cis form. The sandwiched cis form reverts to the trans form only upon decomplexation of F(-). A model pollutant was successfully degraded using the photogenerated NDI-F-NDI sandwich. This opens a wide range of applications in molecular and supramolecular nanotechnology.
可进行反式到顺式光异构化的光开关偶氮苯体系的发现是超分子化学领域的一个里程碑。由于其快速且选择性的开关特性，这类光开关在数据存储、刺激响应递送系统和分子机器等方面具有潜在应用。然而，偶氮苯的光诱导顺式异构体相当不稳定，会通过热和光化学过程恢复到热力学稳定的反式构型。我们首次报道了一种偶氮萘二亚胺（azo-NDI）的可控光开关，它可通过氟离子与阴离子-π相互作用结合来实现。这种NDI-F-NDI“三明治”结构通过生成一个NDI(•-)自由基阴离子和一种双阴离子NDI(2-)物种来稳定顺式构型，该双阴离子在顺式形式下变得异常稳定。只有当F(-)解络合时，夹在中间的顺式形式才会恢复为反式形式。使用光生NDI-F-NDI“三明治”成功降解了一种模型污染物。这为分子和超分子纳米技术开辟了广泛的应用前景。
