Figure 3.

UV‐vis‐NIR spectra of the tetrahydro‐precursor 3 (green) (3×10⁻⁵ M) and the time‐dependent absorption changes of the 7‐PA (red) in dry toluene at RT under Ar (in the absence of light). The insets show the magnified view of NIR region and the absorbance (at 812 nm) of the 7‐PA (under argon) at different time intervals. The 7‐PA was in situ generated by mixing toluene solution of 3 with 2.5 equiv DDQ.