title: Charge transfer (CT) mechanochromism: dramatic CT absorption change of crystalline π-conjugated oligomers containing TCNQ upon mechanical grinding.
abstract: New π-conjugated oligomers with high crystallinity were prepared from the simple solvothermal reaction of squaric acid and diaminopyrenes. The oligomers were bonded at the 1,3- and 1,6-positions of the pyrene units, oligo(sq-alt-1,3py) and oligo(sq-alt-1,6py), which greatly affected their planar configuration and resulting mechanochromic properties. Oligomers containing a charge transfer (CT) complex were selectively synthesized in one step. Upon mechanical grinding in the solid state, the color changed from orange to deep metallic green.
authors.affiliation: Department of Materials Molecular Science, Institute for Molecular Science, National Institutes of Natural Sciences, 5-1 Higashiyama, Myodaiji, Okazaki 444-8787, Japan. nagai@ims.ac.jp.
authors.forename: Atsushi
authors.initials: A
authors.lastname: Nagai
authors.forename: Yuki
authors.initials: Y
authors.lastname: Okabe