title: Bicarbazoles: systematic structure-property investigations on a series of conjugated carbazole dimers.
abstract: A large series of conjugated carbazole dimers, namely bicarbazoles 1-12, were synthesized by Suzuki-Miyaura, Sonogashira, Hay, and McMurry coupling reactions. In 1-12, the two carbazole moieties are linked at the 1-, 2-, or 3-position directly or via an acetylenic or olefinic spacer. The structure-property relationships, particularly the effects of the conjugation connectivity and the π-conjugated spacers on the electronic, photophysical, and electrochemical properties of 1-12, were studied by extensive UV-vis and fluorescence spectroscopic measurements, cyclic voltammetry (CV), and theoretical calculations as well as X-ray crystallographic analyses. The connection at the 1-position of carbazole ensures high extent of π-conjugation, while that at the 3-position enhances the electron-donating ability. Both acetylenic and olefinic spacers allow the extension of π-conjugation, and the latter also causes the increase of the donor ability. Moreover, the structural variations were found to affect the fluorescence quantum yields significantly, which are up to 0.84.
authors.affiliation: Department of Chemistry and Chemical Biology, Graduate School of Engineering, Gunma University, 1-5-1 Tenjin-cho, Kiryu, Gunma 376-8515, Japan.
authors.forename: Shin-ichiro
authors.initials: S
authors.lastname: Kato
authors.forename: Hiroto
authors.initials: H
authors.lastname: Noguchi
authors.forename: Atsushi
authors.initials: A
authors.lastname: Kobayashi
authors.forename: Toshitada
authors.initials: T
authors.lastname: Yoshihara
authors.forename: Seiji
authors.initials: S
authors.lastname: Tobita
authors.forename: Yosuke
authors.initials: Y
authors.lastname: Nakamura
mesh_terms: D002227:Carbazoles / Q000138:chemical synthesis / Q000737:chemistry*; D019281:Dimerization; D008958:Models, Molecular; D015394:Molecular Structure
chemical_list: D002227:Carbazoles; C041514:carbazole