Small Panchromatic and NIR Absorbers from Quinoid Zwitterions
Angélina Torres Ruiz, Manon H. E. Bousquet, Simon Pascal, Gabriel Canard, Valérie Mazan, Mourad Elhabiri, Denis Jacquemin, Olivier Siri
Abstract
The transamination of oxoaminobenzoquinonemonoimine (BQI derivatives), an unconventional zwitterionic quinone, allows isolation of a series of compounds featuring electron-donating aryl auxochromes. The substitution has a very strong impact on the electrochemical and optical features, which is rationalized by theoretical calculations. Protonation and alkylation of the BQIs toward the corresponding cations lead to surprising red-shifts of the absorption, especially in the instance of the most electron-rich dyes that exhibit panchromatic absorption spanning up to the near-infrared (NIR) region, a remarkable achievement for such small molecules.