Mechanofluorochromism of carbazole-type D-pi-A fluorescent dyes

作者：Ooyama Yousuke; Yamaguchi Naoya; Inoue Shogo; Nagano Tomoya; Miyazaki Eigo; Fukuoka Hiroshi; Imae Ichiro; Komaguchi Kenji; Ohshita Joji; Harima Yutaka^*

来源：Tetrahedron, 2012, 68(2): 529-533.

DOI：10.1016/j.tet.2011.11.012

We have newly designed and synthesized unsymmetrical carbazole-type D-pi-A fluorescent dyes. The dyes show a bathochromic shift-type mechanofluorochromism (MFC): grinding of as-recrystallized dyes induces a bathochromic shift of fluorescent color and the fluorescent color is recovered by heating or exposure to solvent vapor. In order to clarify the MFC mechanism for the carbazole-type D-pi-A fluorescent dyes, time-resolved fluorescence spectroscopy, X-ray powder diffractometry, single-crystal X-ray structural analysis, IR spectroscopy, and differential scanning calorimetry are performed before and after grinding of the solids. On the basis of experimental results and semi-empirical molecular orbital calculations (AM1 and INDO/S), we have revealed that the MFC is attributed to a reversible switching between crystalline and amorphous states with changes of intermolecular hydrogen bonding and pi-pi interaction.

• 出版日期2012-1-14