reSeArCH Letter
Extended Data Fig. 3 |^1 H NMR spectroscopy analysis of fjord-type
GNR 2. Observed^1 H NMR spectra of GNR 2 (in Cl 2 CDCDCl 2 at 120 °C)
and dimer 3a (in CD 2 Cl 2 at 22 °C). All of the peaks of 3a range from 7.2
to 7.9 p.p.m. Two doublet-of-doublet peaks appear at a higher magnetic
field (chemical shift δ = 7.2–7.3 p.p.m.), which are attributed to the most
shielded aromatic hydrogen atoms, in the orange-coloured fjord regions.
Other aromatic hydrogen atoms in the fjord regions next to the alkyl
substituents (red circle) are found as a singlet peak at 7.32 p.p.m. On the
other hand, the most deshielded aromatic hydrogen atoms in the bay and
cove regions appear at 7.8–7.9 p.p.m. The^1 H NMR spectrum of fjord-type
GNR 2 shows broadened peaks at 7.0–8.3 p.p.m., which is expected to
reflect the repeating [5]helicene structure.