Preparation of Viscosity-Sensitive Isoxazoline/Isoxazolyl-Based Molecular Rotors and Directly Linked BODIPY–Fulleroisoxazoline from the Stable meso-(Nitrile Oxide)-Substituted BODIPY

We developed a simple methodology for the preparation of stable meso-(nitrile oxide)-substituted BODIPYs, which were characterized by spectroscopic methods and X-ray crystallography. These compounds were used for the preparation of isoxazoline– or isoxazolyl–BODIPYs by 1,3-dipolar cycloaddition reaction with dipolarophiles. Several BODIPYs possess molecular rotor behavior, including viscosity-dependent fluorescence. Transient absorption spectroscopy and time-resolved fluorescence are indicative of a 3 orders of magnitude difference in the excited-state lifetime for dichloromethane and glycerol solutions.