The Role of Hydrazine in Colorimetric Probes Based on Ferrocene Derivative

Two colorimetric and fluorescent probes based on ferrocene derivatives have been designed and synthesized. Among studied anions (F − , AcO − , H 2 PO 4 − , Cl − , Br − and I − ), probe 1 with p -nitrophenyl hydrazine structure has the strongest binding ability for F − , as well as probe 2 for H 2 PO 4 − . It had strong binding ability and was not affected by other anions. The determination limit of 1 toward F − was 5.0×10 −6 mol⋅L −1 which can be used for the trace detection of F − . The interacted process of host–guest accompanied by colorimetric changes and increment in fluorescent intensity of the probes. A 1 H-NMR titration experiment and theoretical investigation indicated that −NH in hydrazine participated in the interaction, and the hydrogen-bonding formed between the probes and anions. These results provided an essential clue to the developing the colorimetric probe based on hydrazine participation.