Arylazopyrazole-functionalized photoswitchable octanuclear Zn(Ⅱ)-silsesquioxane nanocage

• 作者: Kai Sheng Ya-Nan Liu Rakesh Kumar Gupta Mohamedally Kurmoo Di Sun
• 来源期刊: 中国科学：化学（英文版）
• 年，卷（期）: 2021,（3）
• 所属期刊栏目: ARTICLES
• 页码范围: 419-425
• 页数: 7页
• 语种: 英文

摘要

Photoswitchable organic materials have shown significant advancement for photonic applications,however,the polynuclear metal clusters conjugated with photoswitching properties are still formidable.Herein,a novel octanuclear Zn(Ⅱ) nanocage {[Zn8-(Me4Si4O8)2(azopz)8]·4CH2Cl2·MeOH·MeCN} (SD/Zn8) (Hazopz=3,5-dimethyl-4-(phenyldiazenyl)-1H-pyrazole),based on multidentate silsesquioxane and pyrazole modified by photoisomerizable azo group has been designed and synthesized to realize the reversible photoswitching behavior.X-ray crystallographic study reveals that the unique metal core consists of two annular Me4Si4O84-sandwiching a ring of eight Zn atoms where the pyrazole end of azopz-bridges them together.The azopz-ligands diverge above and below the plane defined by eight Zn atoms.Importantly,SD/Zn8 shows quick trans-to-cis transformation upon 365 nm light irradiation,which can be easily changed back by 450 nm light,but slow cis-to-trans reversibility at room temperature as confirmed by UV-Vis and 1H NMR spectroscopies.This process,which presumably regulates the spaces,acts like a pump and is completely repetitive.As such,it can be considered as a molecular pump energized by light.Importantly,the molecule is an energy reservoir where it absorbs the light energy and releases it slowly with time.