A highly selective fluorescence probe for Al3+ based on a new diarylethene with a 6-(hydroxymethyl)picolinohydrazide unit

A new asymmetrical photochromic diarylethene with a 6-(hydroxymethyl)picolinohydrazide unit has been synthesized. Its multichromism behaviors induced by base/acid and light were investigated. The compound exhibited high selectivity and sensitivity toward Al3+, and the fluorescence intensity of the diarylethene was remarkably enhanced by 95-fold and the emission peak was blue-shifted from 585 nm to 542 nm with a concomitant color change from dark to bright green triggered by Al3+. The complexation-decomplexation reaction between the diarylethene and Al3+ was reversible with a binding constant of 1.22 × 104 L mol−1, and the detection limit was determined to be 2.88 × 10−8 mol L−1. Our experimental results demonstrated that the diarylethene could be served as a selective fluorescent sensor for the recognition of Al3+ with high sensitivity and selectivity in methanol.

A novel asymmetrical photochromic diarylethene with a 6-(hydroxymethyl)picolinohydrazide unit was synthesized. Its properties, such as photochromism, multichromism, fluorescence switch and recognition of metal cations were investigated in detail.168