title: Synthesis and crystallochromy of 1,4,7,10-tetraalkyltetracenes: tuning of solid-state optical properties of tetracenes by alkyl side-chain length.
abstract: We synthesized a series of 1,4,7,10-tetraalkyltetracenes using a new 2,6-naphthodiyne precursor and 2,5-dialkylfurans as starting materials (alkyl=methyl to hexyl). Surprisingly, the solid-state color of the tetracenes ranges through yellow, orange, and red. Both yellow and red solids are obtained for the butyl derivative. Optical properties in solution show no marked differences; however, those in the solid state show characteristics that vary with alkyl side-chain length: methyl, propyl, and pentyl derivatives are orange; ethyl and butyl derivatives are yellow; and another butyl and hexyl derivative are red. X-ray analyses reveal that the molecular structures are planar, semi-chair, or chair forms; the chair form takes a herringbone-like arrangement and the other forms take slipped parallel arrangements. The mechanism of crystallochromy is discussed in terms of molecular structure, crystal packing, and calculations that take account of exciton coupling.
authors: Department of Materials Science and Chemistry, University of Hyogo, 2167 Shosha, Himeji, Hyogo 671-2280, Japan. kitamura@eng.u-hyogo.ac.jp
authors: Chitoshi
authors: C
authors: Kitamura
authors: Yasushi
authors: Y
authors: Abe
authors: Takuya
authors: T
authors: Ohara
authors: Akio
authors: A
authors: Yoneda
authors: Takeshi
authors: T
authors: Kawase
authors: Takashi
authors: T
authors: Kobayashi
authors: Hiroyoshi
authors: H
authors: Naito
authors: Toshiki
authors: T
authors: Komatsu