Synthesis, characterization, and evaluation of rhodamine based sensors for nerve gas mimics

Six new rhodamine-B based compounds were synthesized (1–6) and used as fluorescent turn-ON sensors for diethyl chlorophosphate (DCP) in aqueous media at pH 7.0. Compound 1 and 3 gave high fluorescent enhancement with DCP compared to the other compounds. Very high selectivity and sensitivity were observed as these compounds did not show significant fluorescent enhancement with dimethyl methylphosphonate (DMMP), HCl, and metal ions, such as Na+, K+, Ca2+, Cr3+, Mn2+, Fe2+, Co2+, Ni2+, Cu2+, Zn2+, Cd2+, Hg2+, Pb2+. Depending on the way the sensor is presented, results are instantaneous or observed over some minutes.