Penty Samuel E, Appleby Martin V, Zwijnenburg Martijn A, Black Dominic J, Hartmann Denis, Chekulaev Dimitri, Weinstein Julia, Pal Robert, Barendt Timothy A
School of Chemistry, University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK.
Department of Chemistry, University of Durham, South Road, Durham, DH1 3LE, UK.
Chemistry. 2025 Sep 19;31(53):e01734. doi: 10.1002/chem.202501734. Epub 2025 Aug 22.
Chiroptical switches exhibit stimuli-induced changes in the sign or strength of their circular dichroism (CD) or circularly polarized luminescence (CPL) and are materials with significant potential for chiroptical sensing and biological imaging. However, the chromophores used in chiroptical materials usually require excitation by ultraviolet or visible light, which results in higher cytotoxicity and lower penetration compared to near-infrared (NIR) photoexcitation. This can be overcome by multiphoton excitation, yet multiphoton CPL (MP-CPL) has been challenging to measure in organic emitters. Core-twisted perylene diimides (PDIs) are excellent chromophores with which to develop MP-CPL emitters due to a chiral π-system capable of two-photon absorption. Furthermore, the integration of these chiral PDIs into stimuli-responsive macrocycles affords configurational stability and the potential for chiroptical switching, due to the chromophore's tuneable chiral conformation. In this work we report a chiral bis-PDI macrocycle with stable, yet conformationally dynamic, enantiomers, and in doing so realize a novel chiroptical material that combines switchable CD and MP-CPL for the first time.
手性光开关在其圆二色性（CD）或圆偏振发光（CPL）的符号或强度上表现出刺激诱导的变化，是在手性光传感和生物成像方面具有巨大潜力的材料。然而，手性光材料中使用的发色团通常需要紫外光或可见光激发，与近红外（NIR）光激发相比，这会导致更高的细胞毒性和更低的穿透率。这可以通过多光子激发来克服，然而在有机发光体中测量多光子CPL（MP-CPL）一直具有挑战性。由于手性π-体系能够进行双光子吸收，核心扭曲苝二酰亚胺（PDI）是开发MP-CPL发光体的优秀发色团。此外，由于发色团可调节的手性构象，将这些手性PDI整合到刺激响应大环中可提供构型稳定性和手性光开关的潜力。在这项工作中，我们报道了一种具有稳定但构象动态的对映体的手性双PDI大环，并在此过程中首次实现了一种结合了可切换CD和MP-CPL的新型手性光材料。
