Synthesis and aggregation-induced fluorescence emission properties of boron-containing derivatives that respond to viscous alcohols

Abstract

A series of boron-complex-type fluorophores, with enhanced fluorescence emission in the solid state, have been synthesized. When introducing electronic-withdrawing fluorine or electronic-donating phenyl/4-methoxy-phenyl groups on the boron atom, the emissions of these dye compounds in the solid state change from yellow to red. Furthermore, these emissions are affected by viscous alcohols due to their inhibition of the fluorophore's intramolecular rotations. The intensity of the emission is enhanced with increasing viscosity of the alcohol fluids. These dyes with aggregation-induced emission effects are thus expected to find application in estimating the viscosity of transparent viscous fluids.