Pyrene-cored blue-light emitting [4]helicenes: synthesis, crystal structures, and photophysical propertiesElectronic supplementary information (ESI) available: 1H/13C NMR spectra of 6a-c, 7a-d, 8 and 9, TGA curves of 7a-c and 9, packing diagram of 7b, 7c and 9, normalized emission spectra of 7a-c and 9 recorded in thin neat films, cyclic voltammogram (CV) of 7a-c and 9, and summary of crystal data of 7b, 7c and 9. CCDC 778372 (7b), 870212 (7c) and 870213 (9). For ESI and crystallographic data in

• Main Authors: Hu, Jian-Yong, Paudel, Arjun, Seto, Nobuyuki, Feng, Xing, Era, Masanao, Matsumoto, Taisuke, Tanaka, Junji, Elsegood, Mark R. J, Redshaw, Carl, Yamato, Takehiko
• Format: Journal Article
• Language: English
• Published: 06.03.2013
• ISSN: 1477-0520; 1477-0539
• DOI: 10.1039/c3ob27320b

The synthesis, crystal structures and photophysical properties of two types of pyrene-cored blue-light emitting [4]helicenes ( 7 and 9 ) are reported. The chemical structures of all synthesized compounds were fully confirmed by 1 H and 13 C NMR spectra, mass spectroscopy as well as elemental analysis. Single-crystal X-ray analysis of these [4]helicenes revealed that there are two types of laterally naphthalene annulated helical architectures, which are clearly influenced by different R substituents. The photophysical properties of the [4]helicenes ( 7 and 9 ) were fully investigated in both solutions and films, along with the pre-cyclization products, 4,9- and 4,10-bis(phenylethenyl)pyrenes ( 6 and 8 ). Notable optical features were obtained in these compounds, which make them promising candidates for several important applications in modern electronic and optoelectronic devices, such as blue emitters in organic light-emitting devices (OLEDs), or as models for further exploring the development of a new generation of organic materials based on pyrene. Two types of pyrene-cored blue-light emitting [4]helicenes are reported, in which two naphthalene rings of condensed pyrenes were constructed resulting in helical architectures.