Synthesis, structure and photophysical properties of NIR aza-BODIPYs with F/N3/NH2 groups at 1,7-positions

Aza-difluoroboradiaza-s-indacenes were prepared by installation of withdrawing/donating groups at the 1,7-positions. Surprisingly, the effect of the fluorine atom to photophysical properties of dyes 3-6 is trifling, however N3/NH2-containing dyes 9 and 10 resulted in a remarkable bathochromic shift. Aza-BODIPY 10 could be used as a turn-on fluorescent probe for pH value.