Near-Infrared Sensing Properties of Dimethlyamino-Substituted BF₂−Azadipyrromethenes

The synthesis and sensing characteristics of a new class of organic colorimetric and fluorometric chemosensor which operates in the 850−650 nm spectral region is outlined. Judicious placing of amine substituents on the BF₂-chelated tetraarylazadipyrromethene chromophore generates a triple absorption and emission responsive sensor. Dramatic pH responsive absorption and fluorescence changes can be observed across a broad acidity range, from pH 5 to 6 M HCl, in conjunction with a visible colorimetric change from red to purple to blue.