Insights for vibronic effects on spectral shapes of electronic circular dichroism and circularly polarized luminescence of aza[7]helicene

Achieving high circularly polarized luminescence with push–pull helicenic systems: from rationalized design to top-emission CP-OLED applications

“…However, structural and electronic factors that govern the CPL of chiral compounds are still poorly understood even if a few studies have recently tried to rationalize and establish molecular guidelines to obtain high g lum values. 6 …”

CPL calculations of [7]helicenes with alleged exceptional emission dissymmetry values

“…68 Moreover, CAM-B3LYP has been widely employed in CPL calculations of helicenes and helicenoids. 14,37,39,42–44,49…”

“…Our approach is based on time-dependent density functional theory (TD-DFT), 35,36 which in recent years has demonstrated good capability of reproducing CPL data of SOMs, including several helicenes and heterohelicenes. 14,[37][38][39][40][41][42][43][44][45][46][47][48][49][50][51] Conversely, CPL calculations of intramolecular excimers or exciplexes are still relatively limited in number. [52][53][54][55][56] Moreover, with respect to the most common calculation approach, we treated the influence of the solvent by means of the vertical excitation method (VEM), a state-specific (SS) approach to the polarizable continuum model (PCM) for excited states, for which the excited state energy gradients are available, 57,58 going well beyond other SS or the standard linear response (LR) schemes in the PCM.…”

Origin of Chiroptic Amplification in Perylene-Diimide Helicenes

“…37 Vibronic calculations of the electronic spectra of helicenes have already been reported but only for smaller systems and very few electronic states. 38,39 To perform exciton ECD calculations, we defined suitable molecular models made up of different interacting species and computed the couplings between their local excitations with Gaussian 16 as a Coulombic interaction of the transition densities. The ECD spectrum was then obtained with the EXAT program interfaced with Gaussian 16 (additional details in section S8 of the Supporting Information).…”

“…Absorption and ECD spectra have been computed, including the vibronic contributions in Franck–Condon (FC) with the vertical gradient (VG) harmonic model (FC|VG), with the code FCclasses 3.0 by considering the first 50 excited electronic states for both NPDH and NP3H . Vibronic calculations of the electronic spectra of helicenes have already been reported but only for smaller systems and very few electronic states. , …”