Thiophene-based organic dye with large Stokes shift and deep red emission for live cell NAD(P)H detection under varying chemical stimuli.

We report a novel method for synthesizing red and deep red cyanine dyes with large Stokes shifts, probes A and B, for live cell NAD(P)H detection. The probes were prepared using thiophene-based organic dyes featuring a π-conjugated bridge of thiophene and 3,4-ethylenedioxythiophene units linking the 1-methylquinolinium acceptor and formyl acceptor, respectively. These probes display weak absorption peaks at 315 nm (A) and 334 nm (B) and negligible fluorescence in the absence of NADH.