Mechanofluorochromism of heteropolycyclic donor–π-acceptor type fluorescent dyes
2010; Elsevier BV; Volume: 66; Issue: 36 Linguagem: Inglês
10.1016/j.tet.2010.07.018
ISSN1464-5416
AutoresYousuke Ooyama, Genta Ito, Hiroshi Fukuoka, Tomoya Nagano, Yusuke Kagawa, Ichiro Imae, Kenji Komaguchi, Yutaka Harima,
Tópico(s)Porphyrin and Phthalocyanine Chemistry
ResumoThis paper reports that mechanofluorochromism is found for a series of benzofuro[2,3-c]oxazolo[4,5-a]carbazole-type fluorophores (1a–5a) with different p-substituted phenyl groups as acceptor and dibutylamino groups as donor. Grinding of as-recrystallized dyes 1a–3a with strong electron-accepting group induces a fluorescent color change with an enhanced quantum yield and the fluorescent color is recovered by heating or exposure to solvent vapor. On the basis of experimental results and semi-empirical molecular orbital calculations (AM1 and INDO/S), we clarified that the mechanofluorochromism is attributed to a reversible switching between crystalline and amorphous states with changes of dipole–dipole interaction and intermolecular π–π interaction by changes of the densities of the solids before and after grinding.
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