Tri-(2-picolyl)amine-modificated triarylborane: Synthesis, photophysical properties and distinguish for cyanide and fluoride anions in aqueous solution.

We designed and synthesized a tri-(2-picolyl) amine (TPA) functionalized triarylborane, 1-(6-(4-(dimesitylboryl)phenyl)pyridin-2-yl)-N,N-bis(pyridin-2-ylmethyl)methanamine (PB2). The photophysical properties of PB2 were thoroughly explored. Moreover, PB2 can capture CN- and F- in aqueous solution through strong chelation induced by the synergy of a boron atom and metal ion gripped by TPA to display entirely different fluorogenic responses such as fluorescence enhancement for CN- and fluorescence quenching for F- . The results of TOF-MS-EI analysis and theoretical calculations indicate that the complexing of PB2 with CN- formed a 2-to-2 adduct with a stabilized configuration, resulting in strong emission. The complexing of PB2 with F- formed a 1-to-1 adduct with a loose configuration, resulting in weak emission. In pure water, the detection limit of PB2 for CN- is 0.79 μM, and in H2 O/THF (1:9 v/v) system, the detection limits of PB2 for CN- and F- can reach 0.39 and 2.12 μM, respectively, indicating its potential application for effective detection and discrimination of CN- and F- .