Anion response of symmetric hydrazide derivatives: Dependence on the number of hydrazide units

Two symmetric hydrazide derivatives with different numbers of hydrazide groups were synthesized, and their anion responsive behaviors were studied. The UV-vis spectra showed that the compounds with only one hydrazide group can allow highly selective fluoride detection, whereas the compound with two hydrazide groups can respond to F− and AcO−. This is due to the difference in the acidity of the compounds, which is caused by the quantity of hydrazide. This demonstrates that altering the number of hydrazide groups can realize the effective adjustment and control of the anionic recognition ability of compounds.