Synthesis of Pyridyl-Imine Complex of Iron(III) as a Fluorescent Sensor for Hydrazine Detection Based on Redox Chemistry

A six-coordinated iron(III) pyridyl-imine complex was synthesized by one-pot reaction and was demonstrated as a fluorescent sensor for the detection of hydrazine in solution based on the redox reaction. The fluorescence signal generated was attributed to the reduction of the oxidative iron-center of Fe(III) to Fe(II) by the reductive hydrazine. A good linear relationship for the analysis of hydrazine was obtained with the concentration range of 0.06–0.15 mM (R²=0.99114) in DMF solution. The limit of detection (LOD) estimated was 14.8 μM and the limit of quantitation (LOQ) was 49 μM. Moreover, the color change of the iron(III) pyridyl-imine complex solution from dark green to reddish brown was able to observed by naked eye, indicating that the Fe(III)-complex may be also utilized as a colorimetric sensor for hydrazine at millimolar level. The present study demonstrated an interesting fluorescent sensing system based on redox chemistry of an iron(III) complex that generated fluorescence response upon reacting with its redox pair such as the reducing agent hydrazine.