Exploring Dual Solvatochromic Traits in Novel Fluorescent Benzanthrone Ethynyl Derivatives

Motivated by the scarcity of prior research, in this study we report the synthesis and photophysical characteristics of newly obtained benzanthrone ethynyl derivatives. Fourier-transform infrared spectroscopy, ¹H and ¹³C nuclear magnetic resonance spectroscopy and high-resolution mass spectrometry elucidated the structures of the compounds. To study photophysical characteristics, absorbance and emission spectra were measured in solvents with different polarities. Photofading proved high stability of the synthesized compounds (up to 96% of initial absorption after irradiation for 4 h). The analyzed compounds are fluorescent (quantum yields from 0.01 to 0.74 in ethanol) with a significant solvatochromic effect (from 466 nm in benzene to 720 nm in dimethyl sulfoxide). Based on these findings, there is a correlation between the electronic nature of substituents and photophysical parameters. Hence, these compounds could find applications as probes in fluorescence microscopy and sensors to detect polarity variations.