BODIPY-based catenane: Synthesis and optical properties

Abstract

The syntheses of unprecedented bis-triazolyl BODIPY dyes displaying high quantum yields are described. The synthetic approach involves a key alkene metathesis step after templating the two bis-triazolyl dipyrromethenes with Zn, promoting the catenane structure at the expense of the mono-macrocyclic structure. The optical properties of the open form, macrocyclic, and [2]-catenane derivatives are compared. Interestingly, if the fluorescence of both the open and the macrocyclic structure displayed excellent fluorescent properties in dichloromethane, the fluorescence is quenched for the catenane analogue. However, the fluorescence of the catenane can be restored in toluene. A putative explanation for the strong solvent effect is proposed.