Triphasic circularly polarized luminescence switch quantum simulation of a topologically chiral catenane

Abstract

The realm of molecular topology has witnessed a profound paradigm shift with the emergence of chiral catenanes, and their interactions with circularly polarized light are opening new perspectives in the study of chirality. Recently, the first mechanically interlocked platform based on catenane architecture acting as a multi-sequence switch of circularly polarized luminescence (CPL) was expertly designed. This unique chiral luminophore offered us the opportunity to survey the connection between the topological features and its chiral emission properties. In these terms, a theoretical DFT protocol for this CPL spectral prediction is urgent. Herein, we present a robust but accessible computational workflow able to accurately predict a triple-responsive CPL switch (on, off, and boosted signals). Taking advantage of a preliminary DFT benchmark, we decided to use the LC-wHBPE functional to realize a conformational analysis of the pyrene excimer installed in the catenane structure (for the three switchable forms) in the first excited state by means of Born–Oppenheimer molecular dynamics. Consequently, an exhaustive TD-DFT treatment demonstrated the PW6B95D3/6-311G(d,p) level to be the most valuable method to capture skillfully both the band positions and intensities for the on, off and enhanced CPL outputs generated by the interlaced molecular system.