A series of shikimic acid derived pure organic room temperature phosphorescence (PORTP) molecules: Structure, phosphorescence, and versatile sensing applications.

The design of novel-structured pure organic room-temperature phosphorescent (PORTP) molecules and their application in sensing is a cutting-edge direction in RTP research. In this study, a series of molecules featuring an N-aryl benzoxazolone core (named SA series) were synthesized using shikimic acid as the starting material. Single crystals of SA series compounds were successfully grown and subjected to structural analysis. SA series compounds exhibited room-temperature phosphorescence (RTP) both in crystal state and PVA film, confirming the robust phosphorescent nature of the N-aryl benzoxazolone scaffold. The RTP emission wavelength and phosphorescence lifetime of SA series PORTP molecules were tuned by changing the substituents on the N-aryl ring. Notably, the phosphorescence intensity exhibited an inverse correlation with temperature. Specifically, the fluorinated derivative (SA-2) displayed both thermally activated delayed fluorescence (TADF) alongside RTP emission, and was employed for temperature sensing. Morevoer, these PORTP molecules were successfully applied in high-contrast phosphorescence bioimaging in live mice (SNR = 26.50 ± 3.44), advanced anti-counterfeiting technologies, and safety-indicator LEDs. In addtion, the phosphorescence mechanism was elucidated through single-crystal structure analysis, combined with RTP characterization and theoretical calculations.