Ambient stable zwitterionic perylene bisimide-centered radical

David Schmidt; David Bialas; Frank Würthner

doi:10.1002/anie.201408067

Ambient stable zwitterionic perylene bisimide-centered radical

Angew Chem Int Ed Engl. 2015 Mar 16;54(12):3611-4. doi: 10.1002/anie.201408067. Epub 2014 Nov 12.

Authors

David Schmidt¹, David Bialas, Frank Würthner

Affiliation

¹ Universität Würzburg, Institut für Organische Chemie & Center for Nanosystems Chemistry, Am Hubland, 97074 Würzburg (Germany).

PMID: 25393879
DOI: 10.1002/anie.201408067

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.

Keywords: N-heterocyclic carbenes; dyes; perylene bisimides; pigments; radicals.