Ambient Stable Zwitterionic Perylene Bisimide‐Centered Radical

Abstract

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-Cl4 1 with the N-heterocyclic carbene 1,3-di-iso-propyl-imidazolin-2-ylidene ((i)Pr2Im 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)Pr2Im-PBI-Cl4 4 can be transferred reversibly to the corresponding anion and cation, respectively, even on a preparative scale.

Tuning the Energy Gap by Supramolecular Approaches: Towards Near‐Infrared Organic Assemblies and Materials

“…To obtain organic radicals with satisfying stability, great attempts have been made to covalently modify the corresponding organic compounds. [79][80][81] Generally, organic molecules substituted with strong electronwithdrawing moieties favor the formation of stable radical anions, while those substituted with strong electron-donating moieties favor the formation of stable radical cations. In the meantime, there are also several facile ways to realize the stabilization of organic radicals through noncovalent interactions.…”

Recent Advances in Organic Radicals and Their Magnetism

“…We have collated a list of diverse organic neutral radicals , radical anions , radical cations and zwitterionic radicals [132][133][134][135][136] in Charts 1-3 according to the year of their report. It is to be noted that the list is not exhaustive.…”

Perylene Bisimide Radicals and Biradicals: Synthesis and Molecular Properties

“…[11] In this regard, perylene-3,4:9,10-tetracarboxylic acid bisimides (PBIs) with an aromatic perylene core should, in principle,o ffer another promising scaffold for constructing stable functional open-shell systems.A long with other wellrecognized properties of PBIs,s uch as photostability and outstanding fluorescence behavior, [12] recent investigations on PBI derivatives have focused on their applications in photovoltaics and optoelectronic devices by virtue of their n-type semiconducting properties owing to the presence of two electron-withdrawing bisimide subunits. [13] Thec apability of these electron-deficient aromatic bisimides to form fairly stable reduced species [14] was exploited very recently for the isolation of ambient stable PBI radical anions [15] and dianions. [16] Although it is expected that the synthesis of PBI biradicals with open-shell electronic ground states should be feasible owing to the stabilizing effect of the polycyclic and electron deficient aromatic core,there has been no report on the formation and characterization of stable PBI biradicals thus far.…”