A Non‐Hydrolysis Reaction‐Based Imine for Fluorescence Response toward Al3+ Ions with Extremely High Selectivity.

Designing an imine‐based fluorescent probe capable of greatly suppressing the tendency of intrinsic hydrolysis reaction is an attractive topic in the field of chemo‐/biosensing. In this work, hydrophobic 1,1'‐binaphthyl‐2,2'‐diamine containing two amine groups was introduced to synthesize probe R‐1 bearing two imine bonds linked by two salicylaldehyde (SAs). The hydrophobicity of binaphthyl moiety and the unique clamp‐like structure formed from double imine bonds and from ortho‐OH on SA part make probe R‐1 is able to function as an ideal receptor to coordinate with Al3+ ions, leading to the fluorescence originated from the complex rather than from the assumed hydrolyzed fluorescent amine is turned on. Further study revealed that, when Al3+ ions were introduced, both the hydrophobic binaphthyl moiety and the clamp‐like double imine structure in the designed imine‐based probe showed important contributions to suppress the intrinsic hydrolysis reaction, resulting in generating a stable coordination complex with an extremely high selectivity in fluorescence response. [ABSTRACT FROM AUTHOR]