Bicarbazoles: Systematic Structure–Property Investigations on a Series of Conjugated Carbazole Dimers

• Published in: Journal of organic chemistry Vol. 77; no. 20; pp. 9120 - 9133
• Main Authors: Kato, Shin-ichiro, Noguchi, Hiroto, Kobayashi, Atsushi, Yoshihara, Toshitada, Tobita, Seiji, Nakamura, Yosuke
• Format: Journal Article
• Language: English
• Published: WASHINGTON American Chemical Society 19.10.2012; Amer Chemical Soc
• Subjects: Carbazoles - chemical synthesis; Carbazoles - chemistry; chemical reactions; Chemistry; Chemistry, Organic; Dimerization; electrochemistry; Exact sciences and technology; fluorescence; Heterocyclic compounds; Heterocyclic compounds with only one n hetero atom and condensed derivatives; Models, Molecular; moieties; Molecular Structure; Organic chemistry; organic compounds; Physical Sciences; Preparations and properties; Science & Technology; spectral analysis; ultraviolet-visible spectroscopy; X-ray diffraction; LIGHT-EMITTING-DIODES; ELECTROCHEMICAL PROPERTIES; BIPOLAR HOST; COUPLING REACTIONS; BLUE; HOST MATERIALS; TRIPLET EMITTERS; POLY(2,7-CARBAZOLE); PHOTOPHYSICAL PROPERTIES; OLIGOMERS; Acetylenic compound; Molecular structure; Nitrogen heterocycle; Carbazole derivatives; Theoretical study; Fluorescence; Quantum yield; McMurry coupling reaction; X ray diffraction; Suzuki coupling; Cyclic voltammetry; Sonogashira coupling; Electrochemical properties; Olefin; Fluorescence yield; Optical properties; Dimer; Property structure relationship; Conjugated compound; Spectrophotometry; Chemical synthesis; Ethylenic compound; Electron donor; Ultraviolet visible spectrometry
• ISSN: 0022-3263; 1520-6904; 1520-6904
• DOI: 10.1021/jo3016538

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.