Blue-red emitting materials based on a pyrido[2,3-b]pyrazine backbone: design and tuning of the photophysical, aggregation-induced emission, electrochemical and theoretical properties

Abstract

Tuning of opto-electrochemical and theoretical properties of D–A–D-based pyrido[2,3-b]pyrazine amine derivatives by modulating donor groups.

D−A Based 2,3‐di(pyridin‐2‐yl)pyrido[2,3‐b]pyrazine Amine derivatives as Blue‐Orange Emitting Materials: Tuning of Opto‐electrochemical and Theoretical properties

“…The HOMO is mainly located on a donor carbazole ( 7 th position) while LUMO is confined on 2,3‐di(pyridin‐2‐yl ) pyrido[2,3‐ b ]pyrazine acceptor (Figure 8). This observed high separation of HOMO–LUMO and less overlapping between their HOMO–LUMO wave function for this dye is consisted with the principle that ΔE ST value of molecule decreases as the overlap diminishes [15c,d,39b,40a–c] . Further dyes 2 (0.56 eV), 3 (0.57 eV), 4 (0.52 eV), 5 (0.53 eV) and 7 (0.68 eV) showed moderately large ΔE ST values due to D−A induced less significant HOMO and LUMO localization, which leads to a significantly larger singlet–triplet energy gap and a corresponding reduction in the TADF contribution [40d] …”

Oxidized Bis(indolyl)methane Derivatives with Diverse Signaling Units: An Excitation-Dependent Fluorescence Response toward Heavy Metal Pollutants in an Aqueous Medium

“…Interestingly, along with the red-shifted absorption band, prominent tailing was observed in the low-energy region in the aqueous medium (λ abs : 504 nm). This kind of residual absorbance on the longer-wavelength side of the absorption spectrum was probably attributed to the Mie scattering effect, which is common in the case of colloidal nanoaggregates . Moreover, the small red-shifts in the absorption maxima of compounds, upon self-assembly in the aqueous medium, might be attributed to exciton coupling .…”