Ratiometric Fluorescence Acid Probes Based on a Tetrad Structure Including a Single BODIPY Chromophore

A series of tetrad BODIPY derivatives were synthesized. Each molecule was shown to contain phenyl groups at the 1- and 7-positions and a pyridyl or quinolyl group at the 8-position of the BODIPY chromophore. They exhibited fluorescence shifts in the presence of acids. These results imply the importance of controlled conjugation as well as shielding of the meso-substituent from solvents to achieve fluorescence shifts and efficiency through a tetrad structure including a single boron dipyrromethenes (BODIPY) chromophore.