Spectral response to oxy-anions based on ferrocenylphalene

A series of ferrocenyl derivatives (1, 2, 3 and 4) containing phenol group, chemosensors for anions, have been synthesized and optimized. Their binding ability for various anions (F−, Cl−, Br−, I−, AcO− and H2PO4−) were evaluated by theoretical investigation, UV–Vis, 1H NMR titration and cyclic voltammetry experiments and these chemosensors showed strong binding ability for oxy-anions. Theoretical investigation analysis revealed the substituent was different, the space structure was different. And the intramolecular hydrogen bond existed between –OH and other atoms in the structure of these compounds. UV–Vis titrations indicated the anion binding abilities could be tuned by electron push–pull properties of the substituents on the phenyl ortho or para position. Electrochemical titrations showed the addition of anions led to the weak of redox response and the oxidation peak potential moved to more positive potential gradually. In addition, these chemosensors were sensitive to the AcO− detection without the interference of other anions studied, as well as chemosensor 4 was sensitive to the H2PO4− detection.