Azacalixquinarenes: From Canonical to (Poly-)Zwitterionic Macrocycles

Simon Pascal (1) , Lucien Lavaud (1) , Cloé Azarias (2) , Alexandre Varlot , Gabriel Canard (1) , Michel Giorgi , Denis Jacquemin (2) , Olivier Siri (1)

1 CINaM - Centre Interdisciplinaire de Nanoscience de Marseille
2 CEISAM - Chimie Et Interdisciplinarité : Synthèse, Analyse, Modélisation

Azacalixquinarenes, a new family of macrocycles constituted of diaminobenzoquinone diimine units linked by dinitrobenzene rings are synthesized by selected oxidation of the parent azacalixarenes. Crystallographic analyses of two compounds demonstrated the presence of (uncharged) canoni-cal and zwitterionic quinones within a single structure. The electron-withdrawing nature of the dinitrobenzene moieties can trigger the intramolecular H-transfer that generates zwitterionic-ground state quinones. The nature of the N-substituents and the polarity of the solvent have a crucial impact on the equilibrium between the canonical and zwitterionic forms that present distinct optical and electrochemical properties. Thus, within [4]-and [6]-membered macrocycles, poly-zwitterionic structures can be reached, as demonstrated experimentally and theoretically using first-principle approaches .

Domaines: Cristallographie; Chimie organique; Chimie théorique et/ou physique

Simon Pascal, Lucien Lavaud, Cloé Azarias, Alexandre Varlot, Gabriel Canard, et al.. Azacalixquinarenes: From Canonical to (Poly-)Zwitterionic Macrocycles. Journal of Organic Chemistry, 2019, 84 (3), pp.1387-1397. ⟨10.1021/acs.joc.8b02847⟩. ⟨hal-02003222⟩