Correspondingly, the UV-Vis absorption spectrum of ADBr/TEA also developed into a profile that is almost identical to ADBr alone in CH2Cl2 upon HCl titration, with an isosbestic point at 325 nm (Figure ). However, the two doublet peaks at 5.69 and 5.44 ppm in the NMR spectrum of ADBr/TEA also suggest two alternative possible nucleophilic addition sites as shown in Scheme 1, which then produce a set of protons attached to non-aromatic double bonds.