Cover Picture: Synthesis and Characterization of Some Aza[5]helicenes (Eur. J. Org. Chem. 7/2005)

✍ Scribed by Cristina Bazzini; Sergio Brovelli; Tullio Caronna; Cristian Gambarotti; Matteo Giannone; Piero Macchi; Francesco Meinardi; Andrea Mele; Walter Panzeri; Francesco Recupero; Angelo Sironi; Riccardo Tubino

• Publisher: John Wiley and Sons
• Year: 2005
• Tongue: English
• Weight: 55 KB
• Volume: 2005
• Category: Article
• ISSN: 1434-193X
• DOI: 10.1002/ejoc.200590014

✦ Synopsis

Abstract

The cover picture shows the structure of 5‐aza[5]helicene (top) and the crystal packing (single enatiomers, bottom). This is one of the aza[5]helicenes reported in the paper that were synthesized by photochemical ring closure of suitable ethenyl derivatives. The photophysical properties (very long triplet‐state lifetime) and crystal packing (columnar arrangement) were studied and shown to be dependent on the nitrogen position. These molecules may be suitable for studies on π−π interactions and complexation with metal ions. The extremely long triplet lifetime that was observed (in the range of seconds) makes these molecules promising candidates for practical applications in photo‐ and optoelectronics. Details are discussed in the article by T. Caronna et al. on p. 1247 ff.