title: Photocontrol over self-assembled nanostructures of π-π stacked dyes supported by the parallel conformer of diarylethene.
abstract: Diarylethenes (DAEs) have rarely been used in the design of photoresponsive supramolecular assemblies with a well-defined morphology transition owing to rather small structural changes upon photoisomerization. A supramolecular design based on the parallel conformation of DAEs enables the construction of photoresponsive dye assemblies that undergo remarkable nanomorphology transitions. The cooperative stacking of perylene bisimide (PBI) dyes was used to stabilize the parallel conformer of DAE through complementary hydrogen bonds. Atomic force microscopy, UV/Vis spectroscopy, and molecular modeling revealed that our DAE and PBI building blocks coassembled in nonpolar solvent to form well-defined helical nanofibers featuring J-type dimers of PBI dyes. Upon irradiating the coassembly solution with UV and visible light in turn, a reversible morphology change between nanofibers and nanoparticles was observed. This system involves the generation of a new self-assembly pathway by means of photocontrol.
authors.affiliation: Department of Applied Chemistry and Biotechnology, Graduate School of Engineering, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba 263-8522 (Japan); CREST, JST, Chiyoda-ku 102-0075 (Japan). yagai@faculty.chiba-u.jp.
authors.forename: Shiki
authors.initials: S
authors.lastname: Yagai
authors.forename: Kazunori
authors.initials: K
authors.lastname: Iwai
authors.forename: Mitsuaki
authors.initials: M
authors.lastname: Yamauchi
authors.forename: Takashi
authors.initials: T
authors.lastname: Karatsu
authors.forename: Akihide
authors.initials: A
authors.lastname: Kitamura
authors.forename: Shinobu
authors.initials: S
authors.lastname: Uemura
authors.forename: Masakazu
authors.initials: M
authors.lastname: Morimoto
authors.forename: Hao
authors.initials: H
authors.lastname: Wang
authors.forename: Frank
authors.initials: F
authors.lastname: Würthner
keywords: diarylethenes; perylene dyes; photochromism; self-assembly; supramolecular chemistry