Ultrafast and reversibly cyclization/cycloreversion of 4-imino-4H-Quinolizine-1-Carbonitrile: A new strategy for fluorescence modulation in pH sensing in living cells

Reversible chemically stimulated cyclization/cycloreversion reactions are of great interest and highly demanding for developing molecular switches, such as fluorescent probes. Herein, ultrafast and reversible cyclization/cycloreversion reactions of 4-imino-4H-quinolizine-1-carbonitrile (IMQU) derivatives, induced by H+/OH−, were developed as a new strategy for pH sensing. 1H NMR, HRMS techniques and quantum chemical methods applied to the pH...