Selective photoinduced single or double electron reduction of perylenebisimides

Selective single and double electron reduction of two soluble perylenebisimides was performed by irradiating these compounds in benzonitrile solutions containing triethylamine 10−2 M. Lamp irradiation in the absence of oxygen generates, consecutively, the corresponding radical anion and dianion as persistent species, depending of the irradiation time. These negative PBI species were persistent long enough to be characterized by optical and EPR spectroscopies. Laser flash photolysis determines that the kinetics of PBI reduction follows two first order processes assigned to the presence of two different populations of solvated electrons in the medium. The fastest reduction takes place in tens of microseconds and the slowest occurs with a lifetime longer than hundred microseconds.

► Photolysis of a triethylamine solution in benzonitrile at 355 nm ejects electrons. ► Perylenebisimides act as electron acceptors and form persistent radical anions. ► Radical anions can be characterized by steady-state EPR spectroscopy. ► Radical anions can be further irradiated to perylene dianions.