Fig. 4. Representative properties of (12,12)-NpNT.

a Absorption and fluorescence spectra of (12,12)-NpNT (1.2 × 10⁻⁶ M in CH₂Cl₂, 25 °C). b Histogram sorting 213 orbitals of (12,12)-NpNT by energy on the basis of the DFT calculations. Orbitals originating from pyridine units are coloured in red (occupied) and blue (unoccupied). See Supplementary Fig. 9 for details. c Representative Kohn–Sham orbitals. d Absorption and fluorescence spectra of (12,12)-NpNT (1.2 × 10⁻⁶ M in CH₂Cl₂, 25 °C) in the presence of trifluoroacetic acid (7.4 × 10⁻³ M).