Synthesis, optical properties, and application of novel chalcone skeleton as pH fluorescent probe: Based AIE + ESIPT strategy.

[Display omitted] • A series of chalcone skeleton were synthesized with high yield up to 97%. • The molecules were based on AIE + ESIPT stagey. • The compound could be used as "On-Off" probe for basic system. • The compound showed excellent selectivity and sensitivity for pH. • The compound exhibited low biotoxicity and stability in cell. A series of "turn off" pH fluorescence probes with chalcone skeleton for basic system have been developed. The molecules emitted bright yellow fluorescence under acidic condition, resulting AIE coupled ESIPT characteristic and ICT process. What's more, the compounds exhibited excellent sensitivity and selectivity for detecting pH as a facile "On-Off" fluorescence probe, and the fluorescence of them were quenched with the ESIPT process interrupted under alkaline condition. Theoretical calculation for the related compounds also performed to verify the electron effect on photophysical properties and confirm the rational speculation on the mechanism. [ABSTRACT FROM AUTHOR]