Formation of two isomers in the replacement reactions of bay area dibromine atoms in perylene diimides

Abstract

Three reaction mechanisms were reported in the replacement reaction of bay area dibromine atoms in perylene diimide derivatives in previous studies. However, the effect of the reaction solvents and intermediate compound (perylene diimide radical anion) on the reaction mechanisms and product structure had not been reported. Here, we report the role of the reaction solvents and the perylene diimide radical anion in replacement reactions of bay area dibromine atoms of perylene diimide. Two isomers in the replacement reactions of bay area dibromine atoms in perylene diimides were found when using proton solvents (such as ethanol), and presenting the about 41% 1-bromo-7- ethoxy substituted perylene diimide derivative changed into 1,6- diethoxy substutent perylene diimide derivative in double substituted reaction. In polar non-proton solvents, inorganic base (K2CO3) can induce dibromo perylene diimide to form its radical anion. Further, the substitution reactions is a SN1 mechanism in proton solvents, and the substitution reactions is belong to a SN2 and SRN1 mechanism in polar non-proton solvents.