Improved Solvatochromism and Quantum Yields in Acridine through Polarity-Enhanced π-Conjugation
Jiancheng Zhou, Yan Jiang, Qingwei Jiang, Simin Lin, Zhouyu Chen, Mengyu Ji, Xinyu Gou, Lingya Peng, Yu Fang
Abstract
Fluorophores exhibiting strong solvatochromism are strongly desired for applications in cellular imaging, photodevices, and fluorescence sensing. However, achieving high quantum yields in increasingly polar environments remains a significant challenge due to the complex balance required between a high transition dipole moment and a low emission energy. In this study, we present an acridine derivative of pyrene, Ad-Py, which features a donor-π-acceptor (D-π-A) scaffold. Notably, this fluorophore demonstrated a strong solvatochromic property, exhibiting a red-shift of 113 nm, along with high quantum yields ( Φ f = 83.5–90.6%) from the less polar solvent n -hexane to the highly polar solvent dimethyl sulfoxide (DMSO). The incorporation of the pyrene moiety effectively extended the π-conjugation of Ad-Py in polar solvents and finely tuned the proportion of the charge transfer (CT) state, leading to enhanced quantum yields. Moreover, due to its sensitivity to microenvironmental changes, Ad-Py facilitated the visual measurement of SO 2, achieving a detection limit of <10 ppb.