Click Chemistry Derived Hexa-ferrocenylated 1,3,5-Triphenylbenzene for the Detection of Divalent Transition Metal Cations

Abstract

The 1,3-dipolar cycloaddition reaction (click chemistry approach) was employed to create a hexa-ferrocenylated 1,3,5-triphenylbenzene derivative. Leveraging the presence of metal-chelating sites associated with 1,2,3-triazole moieties and 1,4-dinitrogen systems (ethylenediamine-like), as well as tridentate chelating sites (1,4,7-trinitrogen, diethylene triamine-like) systems, the application of this molecule as a chemosensor for divalent transition metal cations was investigated. The interactions were probed voltammetrically and spectrofluorimetrically against seven selected cations: iron(II) (Fe 2+ ), cobalt(II) (Co 2+ ), nickel(II) (Ni 2+ ), copper(II) (Cu 2+ ), zinc(II) (Zn 2+ ), cadmium(II) (Cd 2+ ), and manganese(II) (Mn 2+ ). Electrochemical assays revealed good detection properties, with very low limits of detection (LOD), for Co 2+ , Cu 2+ , and Cd 2+ in aqueous solution (0.03–0.09 μM). Emission spectroscopy experiments demonstrated that the title compound exhibited versatile detection properties in solution, specifically turn-off fluorescence behavior upon the addition of each tested transition metal cation. The systems were characterized by satisfactory Stern–Volmer constant values (10 5 –10 6 M –1 ) and low LOD, especially for Zn 2+ and Co 2+ (at the nanomolar concentration level).