Mechanical force induced reversible fluorescence switching of two 3-aryl-2-cyano acrylamide derivatives
作者:Qingbao Song、Kang Chen、Jingwei Sun、Yongsheng Wang、Mi Ouyang、Cheng Zhang
DOI:10.1016/j.tetlet.2014.04.024
日期:2014.5
Two structural-simple 3-aryl-2-cyano acrylamide derivatives (CDPA-E and CDPA-P) were synthesized and characterized by NMR, MS, IR, and single crystal. It was found that both of them exhibited obvious piezofluorochromic properties. The as-prepared yellow-green compounds were both converted to orange-red after grinding with a spatula. All the ground samples can be recovered to its original color by heating at 80 degrees C over 5 min or fuming with solvents like DCM, ethanol, ethyl acetate etc. The changes in fluorescence color can be attributed to the phase transition between crystalline (order) state and amorphous (disorder) state according to the Powder XRD spectrum. At the molecular level, the extension of the conjugation length and the formation of excimers are confirmed to account for the color transition of CDPA-P and CDPA-E, respectively. In addition, CDPA-P exhibited AIE activity which was caused by the restricted rotation of the molecules in the crystal state. (C) 2014 Elsevier Ltd. All rights reserved.