Qingdao Institute of Energy, Chinese Academy of Sciences: New progress in the synthesis of new artificial muscle modules

Recently, researcher Wan Xiaobo, who was selected as the "Hundred Talents Program" of the Bio-Energy and Process Research Institute of the Chinese Academy of Sciences in Qingdao and a researcher of the bio-based polymer materials team, developed a new diazocine synthesis method. Published in the latest issue of Organic Letters (A Rapid and Efficient Access to Diaryl-ibenzo[b,f][1,5]diazocines, Org. Lett., 2011). Diazocine is an antiaromatic heterocyclic ring with 8 π-electron structures. It is in the ship-like conformation in the neutral state, but it can obtain 2 electrons in the electrochemical reduction state, and it becomes aromatic. The heterocyclic ring in the planar conformation, and this process is reversible. During the transition from the ship-like conformation to the plane conformation, the linear distance between the two ends of the diazocine molecule will change, and therefore, it can be regarded as a basic building block for a new artificial muscle. Diazocine is generally prepared by 2-aminobenzophenone through a conventional condensation reaction, but this process requires a long period of reflux and water removal, and the yield is greatly affected by the substrate. In addition, the preparation of 2-aminobenzophenone itself is cumbersome and expensive, thus limiting the study of the properties of diazocine molecules. Wan Xiaobo et al. used phthalic anhydride and substituted benzene as starting materials to obtain diazasulfonine through a three-step reaction. Among them, the key reaction step is the cyclization reaction of 2-acyl azide benzophenone under acidic conditions. This reaction does not require long reflux and water removal, and the reaction is rapid and the yield is high. At the same time, Wan Xiaobo et al. also studied the mechanism of the ring reaction, and determined that this is a novel [2+2] ring reaction. At present, the team is working on the synthesis of artificial muscles of diazaocin that are based on the results of this study.