# Dynamics and Conformational Stability of Chiral Bay‐Phenolate‐Substituted Twisted Octaazaperopyrenedioxides (OAPPDOs)

## TL;DR

Researchers created stable chiral fluorophores by adding BINOL units to OAPPDOs, enabling the study of their chiroptical properties like CPL.

## Contribution

The paper introduces a new class of chiral fluorophores with conformational flexibility and high thermal stability.

## Key findings

- Chiral OAPPDO derivatives show remarkable thermal stability and low racemization.
- DFT modeling revealed an activation barrier above 170 kJ mol−1 for racemization.
- The fluorophores exhibit circular polarized luminescence with a g_lum of 2×10−4.

## Abstract

Configurationally stable chiral octaazaperopyrene dioxide (OAPPDO) derivatives were obtained by nucleophilic substitution of chiral BINOL and related fragments as bridging units onto the bay position. The addition of these phenolate derivatives has given rise to a new group of bright chiral fluorophores with remarkable thermal stability, which allowed the study of their chiroptical properties, in particular, their circular dichroism characteristics as well as circular polarized luminescence (CPL), albeit with a low dissymmetry factor (g
lum) in the range of 2*10−4. The introduction of the BINOL bridging groups in the bay position led to equilibria between chiral conformers in solution, the interconversion of which has been studied by DFT modeling, with the two lowest energy species being directly observable in situ by NMR. Insight into the stability of these derivatives with respect to overall racemization has been obtained by DFT modeling which established an overall activation barrier for the process of above 170 kJ mol−1.

Chiral octaazaperopyrenedioxide (OAPPDO) fluorophores were obtained by functionalizing with BINOL and related fragments bridging the bay position. They possess conformational flexibility but remarkable thermal stability with respect to racemization of the central chromophore, which allowed the study of their chiroptical properties, including circular polarized luminescence (CPL).