Oxindole-Terminated Quinoidal Compounds with Ultrahigh Electron Affinity: Synthesis and Applications.

Six quinoidal compounds terminated by oxindole have been synthesized via selective nucleophilic addition, dehydroxylation, and oxidation. Through the modification of the quinoidal core and terminal benzene rings with fluoride atoms or cyano groups, the LUMO energy levels of the quinoidal compounds can be tuned within the range -4.05 to -4.54 eV. The quinoidal molecules exhibited electron transport behavior and can be used as dopants to dope an oligo(ethylene glycol)-substituted polythiophene.