Synthetic Potentials of Heptamethine Merocyanine Dyes Containing an Active Chlorine Atom: Reactivity towards Nucleophiles

The reactivity of heptamethine merocyanine dyes that contain an active chlorine atom at a meso position of the polymethine chain towards nucleophiles is investigated for the first time. The reactivity differs completely from that of cationic cyanine dyes and is consistent with a concerted SNAr addition–elimination mechanism. This mechanism is additionally supported by the performed DFT calculations in the gas phase and in solution. The observed dependence of the reaction on the type of the nucleophilic agents is dis