A Nitrogen‐Doped Hexapole [7]Helicene versus Its All‐Carbon Analogue

Two synthetic nanographenes (NGs), N‐H7H and C‐H7H, were prepared. N‐H7H is doped with nitrogen, and C‐H7H is the all‐carbon analogue. Both are hexapole [7]helicenes (H7Hs), and their structures were identified by single‐crystal X‐ray diffraction. Sharp contrasts in absorption (absλmax, 683 vs. 593 nm), emission (emλmax, 894 vs. 777 nm), and electrochemical behavior (oxE1, 0.28 vs. 0.53 V) were observed between N‐H7H and C‐H7H, and the origin of these differences was rationalized by theoretical calculations. Studies on N‐H7H and C‐H7H set a clear example to elucidate the remarkable effects of N‐doping on the physical properties of NGs. Nitrogen doping: A pair of synthetic nanographenes (NGs), nitrogen‐doped N‐H7H and its all‐carbon congener C‐H7H, were investigated (see picture). Their comparison illustrates the effects of N‐doping on the physical properties of NGs, with minimized interference from shape, size, and functional groups.