Delocalisation in conjugated triazene chromophores: Insights from theory

The structures and electronic spectra of four conjugated triazenes have been investigated with a combination of the time-dependent density functional theory and the polarisable continuum model. Aside from reproducing the experimental geometries and absorption wavelengths, the proposed theoretical scheme allows (i) to assess the delocalisation of the triazeno pattern (ii) to explain the shape of the experimental absorption bands (iii) to unravel an excited-state switching when using push–pull auxochroms.