Intrinsic Multicolor Emissive Aliphatic Linear Polyphosphate Esters From the Charge-Transfer-Induced Enhanced Spatial Electronic Communication

Unconventional fluorescent polymers are attracting increasing attention because of their excellent biocompatibility and wide applications. However, these polymers typically exhibit weak long-wavelength emission. Herein, three novel aliphatic linear polyphosphate esters are prepared via a one-pot polycondensation reaction. Such polymers can generate strong blue, green, yellow, and red fluorescence under different excitations. Experimental and theoretical results showed that the cluster of C═C and phosphate ester groups attracted the negative charge of isolated functional groups, and the alkane chains and hydrogen atoms also provided a negative charge for spatial electronic communication. Then, intrinsic fluorescence arises from the charge-transfer-induced enhanced spatial electronic communication. Additionally, these polymers show potential applications in fluorescence film, ion detection, bacteria imaging, and visualization of the NaCl crystallization process. This work provides a universal design strategy for developing strong long-wavelength emissive polymers and gains new insight into intrinsic emission mechanisms.