A triazole based triferrocene derivative as a multiresponsive chemosensor for Hg(II) ion and a redox chemosensor for H_2PO_4 - ion

摘要

A triazole tethered triferrocene receptor, C_(40)H_(40)O_2N_6Fe_3 3, has been synthesized from the reaction of mono-alkynyl substituted ferrocene, 1 and 1,1′-bis-(azidomethyl)ferrocene, 2. Consequently the cation and anion sensing properties of 3 have been examined. The receptor 3 was found to be highly selective electrochemical (ΔE~1_(1/2)=145mV, ΔE~2_(1/2)=92mV), optical and chromogenic chemosensor for Hg~(2+) ion in aqueous environment. The substantial changes in its absorption spectra are accompanied by the appearance of a new low-energy peak at 631 nm (ε = 3400 M~(-1) cm~(-1)). This is also accompanied by a strong color change from yellow to purple, that allows a prospective for the "naked eye" detection of Hg~(2+) ion over other competitor cations such as Pb~(2+), Cd~(2+), Zn~(2+), etc. In addition, among various anions, 3 shows a distinct electrochemical recognition of dihydrogen phosphate anion by its multiple H-bonding (C-H?O), which is supported by electrochemical (large cathodic shift ΔE_(1/2) = -175 mV) and 1H NMR titration results.