Conformationally Restricted α, α Directly Linked BisBODIPYs as Highly Fluorescent Near-Infrared Absorbing Dyes

A new family of α, α directly linked bisBODIPYs was developed through a MoCl5-mediated intramolecular oxidative reaction. Due to the coplanar structure of the two conformationally locked BODIPY units, these bisBODIPYs showed well-extended conjugations and gave strong near-infrared absorptions and emissions with maxima around 760 and 780 nm, respectively, with high fluorescence quantum yields of ≤0.84. These dyes were successfully applied for in vitro and in vivo fluorescence imaging by taking advantage of their beneficial photophysical properties.