Red edge effect of chalcone derivatives and their application in Bio-sensing.

A series of chalcone-based compounds with varied functional groups were designed and synthesized through green chemistry. Polarity-tuned solvatochromic photophysical studies were thoroughly performed using steady-state absorption and emission spectroscopic techniques. These donor-acceptor structured chalcones were capable of exhibiting excitation dependent fluorescence (EDF), which is widely known as the red edge effect, with a large Stokes shift above 140 nm, making them capable of accessing the yellow to blue region of the spectrum. Furthermore, the ease of tuning the fluorescence property was utilized in the field of biosensors to obtain tunable brilliant blue to green colors for the first time. Computational studies indicated the presence of relatively compact states, which might be one of the key factors responsible for the red edge effect.