A Novel, Dual-Response Chemosensor Based on Ferrocene Derivative for the Selective Detection of Al3+ Ions : Fluorescence and Electrochemical Signaling

A new Chemosensor, 5-ferrocenylsalicylaldehyde-2-pyridinehydrazone ( SP-Fc ), was designed and synthesized by condensing 5-ferrocenylsalicylaldehyde with 2-hydrazinopyridine. Its structure was characterized by 1 H NMR, 13 C NMR and HRMS. SP-Fc could be used to identify Al 3+ through dual optical and electrochemical responses. Upon addition of Al 3+ , The probe exhibited a significant fluorescence enhancement attributed to CHEF and the inhibition of both PET and ESIPT processes. The probe specifically regonized Al 3 +  in a wide pH range and had a well linear range (0-200 µM). Job’s plot analysis revealed that the interaction of SP-Fc with Al 3+ was 1:1 binding stoichiometry. The detection limit of probe for Al 3+ was observed as low as 1.30 × 10 − 7 M. The response mechanism of SP-Fc to Al 3 +  was confirmed through NMR titration experiment. Additionally, the electrochemical signals of SP-Fc in the presence of the Al 3+ was shifted significantly compared with those of the other metal cations tested. Moreover, Confocal fluorescence microscopy imaging demonstrated that SP-Fc can monitor Al 3+ in living MCF-7 cells with low cytotoxicity. This showcases SP-Fc ’s promise for biological system and analytical chemistry, providing a robust tool for Al 3 +  detection in diverse settings.