2,7-Diferrocenyl-3,6-diazaocta-2,6-diene: A highly selective dual fluorescent sensor for Zn²⁺and Ag⁺and electrochemical sensor for Zn²⁺

Abstract

2,7-Diferrocenyl-3,6-diazaocta-2,6-diene (DFDD), obtained by condensation reaction of acetylferrocene and ethylenediamine, exhibits Zn²⁺ ion-induced enhancement of fluorescence intensity and Ag⁺ ion-induced quenching of fluorescence intensity. The Zn²⁺ ion shifts the redox potential of DFDD from +0.660 V ± 0.005 V to + 0.615 ± 0.005 V as observed by cyclic voltammetry and square wave voltammetry. Ca²⁺, Mg²⁺, Mn²⁺, Fe²⁺, Co²⁺, Ni²⁺, Cu²⁺, Cd²⁺, Pb²⁺ and Hg²⁺ have very little effect on fluorescence intensity of DFDD. These metal ions together with Ag⁺ ion have no effect on the electrochemistry of DFDD. Both, fluorescence and UV-visible spectroscopic data show a 1:1 interaction between DFDD and Zn²⁺ with binding constant 75 <i style="">M</i><i style=""></i>^-1. The applicability of DFDD as fluorescence sensor for Zn²⁺ ion has been shown in its estimation in commercial tablets.