Intense absorption of azulene realized by molecular orbital inversion

Chem Commun (Camb). 2023 Aug 31;59(71):10604-10607. doi: 10.1039/d3cc02311g.

Abstract

The introduction of diarylamino groups at the 2- and 6-positions of azulene was found to invert the order of the orbital energy levels and allowed the HOMO-LUMO transition, resulting in a substantial increase in absorbance in the visible region. In addition, the stability of their one-electron oxidised species was improved by introducing bromine or methoxy groups at the 1- and 3-positions.