Unprecedented Intramolecular Electron Transfer from Excited Perylenediimide Radical Anion

Abstract

Radical anions in the excited states can be treated as stronger reductants than those in the ground states. In this study, the intramolecular electron transfer (ET) processes from the excited perylene-3,4,9,10-tetracarboxydiimide radical anion (PDI•–*) were examined for the first time by applying the femtosecond laser flash photolysis to the dyads of PDI and acceptors (PDI-A). Efficient intramolecular ET from PDI•–* was detected upon the excitation of PDI•–-pyromellitimide (PI) and PDI•–-naphthalenediimide (NDI) because of the sufficient driving forces. In particular, unprecedented ET processes were confirmed in a PDI-PDI dimer. Excitation of PDI•–-PDI gave the shortest PDI•–* lifetime due to the fastest intramolecular ET. Surprisingly, an intramolecular disproportionation reaction generating the dianion of PDI and neutral PDI was confirmed upon the excitation of PDI•–-PDI•–. These processes successfully simulated the photocarrier (polaron and bipolaron) generations in PDI-based n-type semiconducting mate...