Photoinduced Bending of a Large Single Crystal of a 1, 2‐Bis(4‐pyridyl)ethylene‐Based Pyridinium Salt Powered by a [2+2] Cycloaddition1. (21st May 2013) - Sun, Jian‐Ke; Li, Wei; Chen, Cheng; Ren, Cai‐Xia; Pan, Dan‐Mei; Zhang, Jie