N -Annulated [5]Helicenes: Syntheses, (Anti)Aromaticity and Properties
Abstract
N -Annulated [5]helicene ( NH5 ) and its dibenzo-extended derivatives are synthesized by cycloisomerization and Scholl-type cyclodehydrogenation methods, respectively. Nitrogen-bridging of fjord -carbons 1 and 14 of [5]helicene endows saddle-like NH5 featuring an antiaromatic azepine core with enhanced orbital overlap between nitrogen and the carbon π-system. N -Annulation results in less stabilized HOMO, a smaller HOMO–LUMO energy gap, red-shifted absorption, fluorescence, paratropic ring current over the azepine unit, and tunable aromaticity of the core relative to pristine [5]helicene. The NH5 derivatives exhibit space-charge-limited current hole mobility on the order of 10 –3 cm 2 V –1 s –1, which is higher than that of N -annulated PAH, like N -annulated perylene.
Fields of Study & Subjects
Synthesis and Properties of Aromatic Compounds
Photochromic and Fluorescence Chemistry
Fullerene Chemistry and Applications
Publication details
- Journal / source
- Organic Letters
- Publisher
- American Chemical Society (ACS)
- Volume
- 28
- Issue
- 7
- Pages
- 2260–2265
- Publication date
- 9 February 2026
- Language
- EN