Carbo-quinoids: stability and reversible redox-proaromatic character towards carbo-benzenes

Kévin Cocq; Valérie Maraval; Nathalie Saffon-Merceron; Alix Saquet; Corentin Poidevin; Christine Lepetit; Remi Chauvin

doi:10.1002/anie.201407889

Carbo-quinoids: stability and reversible redox-proaromatic character towards carbo-benzenes

Angew Chem Int Ed Engl. 2015 Feb 23;54(9):2703-6. doi: 10.1002/anie.201407889. Epub 2015 Jan 21.

Authors

Kévin Cocq¹, Valérie Maraval, Nathalie Saffon-Merceron, Alix Saquet, Corentin Poidevin, Christine Lepetit, Remi Chauvin

Affiliation

¹ CNRS, LCC (Laboratoire de Chimie de Coordination), 205 route de Narbonne, BP44099, 31077 Toulouse Cedex 4 (France); Université de Toulouse, UPS, ICT-FR 2599, 31062 Toulouse Cedex 9 (France).

PMID: 25612252
DOI: 10.1002/anie.201407889

Abstract

The carbo-mer of the para-quinodimethane core is stable within in a bis(9-fluorenylidene) derivative. Oxidation of this carbo-quinoid with MnO2 in the presence of SnCl2 and ethanol affords the corresponding p-bis(9-ethoxy-fluoren-9-yl)-carbo-benzene. The latter can be in turn converted back into the carbo-quinoid by reduction with SnCl2 , thus evidencing a chemical reversibility of the interconversion between a pro-aromatic carbo-quinoid and an aromatic carbo-benzene, and is reminiscent of the behavior of the benzoquinone/hydroquinone redox couple (in the red-ox opposite sense).

Keywords: X-ray diffraction; alkynes; aromaticity; heterocycles; quinodimethanes.