Ferrocenylated 1,3,5-triphenylbenzenes for the electrochemical detection of various cations or anions

Three diverse 1,3,5-triphenylbenzene derivatives bearing three ferrocene units (Fc1–Fc3) were used for the construction of electrochemical sensors for the detection of various cations or anions. The obtained derivatives contained imine (Fc1 and Fc2) or amide bonds (Fc3) between 1,3,5-triphenylbenzene and ferrocene skeletons, which further influenced the ability of the as-synthesized ferrocenylated molecules to recognize cations (Cu(II), Pb(II), Cr(III) and Fe(III); compounds Fc1 and Fc2) or monovalent anions (Br−, I−, ClO4−, NO3−, CH3COO−, and H2PO4−; compound Fc3). In the case of cation recognition, differential pulse voltammetry (DPV) experiments revealed that the Fc1 receptor was characterized by much better sensitivity compared to the Fc2 receptor and the limit of detection (LOD) values ranged from 0.5 to 1.8 μM. Similarly, such very low LOD values (0.7–1.5 μM) were also found in the case of anion recognition by the Fc3 receptor. Importantly, the advantage of the tested Fc receptors is also their long-term stability (sensors were stable at least for 2 months).