Ambient Stable Zwitterionic Perylene Bisimide-Centered Radical

The unexpected introduction of a cationic imidazolium substituent in the 2-position of a tetrachloro-substituted perylene-3,4: 9,10-tetracarboxylic acid bisimide (PBI) by the reaction of PBI-Cl-4 1 with the N-heterocyclic carbene 1,3-diiso- propyl-imidazolin-2-ylidene ((i)Pr(2)Im 2) enables the isolation of an ambient stable zwitterionic radical. The remarkable stability of this unprecedented PBI-centered radical facilitates the complete characterization by several spectroscopic methods as well as single crystal structure analysis. Redox studies revealed that (i)Pr(2)Im-PBI-Cl-4 4 can be transferred reversibly to the corresponding anion and cation, respectively, even on a preparative scale.