An Efficient Molecular Tool with Ferrocene Backbone: Discriminating Fe³⁺ from Fe²⁺ in Aqueous Media

Abstract

Two novel molecular probes with ferrocene backbone have been designed and synthesized for the first time, and they were subsequently found capable of distinguishing Fe3+ and Fe2+ ion in aqueous media. The discrimination of both the oxidation states (II/III) of iron by these receptors can be established either from a striking shift in redox potential (1: ΔE 1/2 ≈ 90 mV and 2: ΔE 1/2 ≈ 59 mV) for Fe2+ ion or from UV–vis absorption studies (using light-absorption ratio variation approach (LARVA)). Moreover, the discrimination of Fe2+ and Fe3+ cations could be performed by naked-eye observation because of the development of different colors upon interaction with these probes which act as indicators for the in situ qualitative detection of Fe3+ and Fe2+. The limits of detection of Fe2+ and Fe3+ cations with receptor 2 were found to be as low as 30 and 15 parts per billion (ppb), respectively. The probable binding modes of these receptors with Fe2+ have also been suggested on the basis of the 1H NMR spectroscopic titration, electrospray ionization mass spectrometry (ESI-MS), Job’s plot, and computational (DFT) studies along with electrochemical and spectro-photochemical data. Single crystal X-ray diffraction analysis of 1 revealed that its solid-state structure was stabilized via intermolecular C–H/O and O–H/N hydrogen bonds and by C–H/π interactions. Interestingly, detailed theoretical calculations (DFT) indicated that hydroxymethyl (−CH2OH) group attached to naphthalene unit plays a pivotal role in sensing Fe2+/3+ ion selectively and in the stabilization of 2 in unusual eclipsed configuration through C–H···O type hydrogen bonding.

Antioxidant status anticancer and hepato protective efficacy of Macrotyloma uniflorum seeds an In-vitro approach

“…Since, antioxidant molecule converts (through electron transfer reaction) the ferric (Fe 3+ ) into ferrous (Fe 2+ ) (Zhou et al, 2021). While this ferric (Fe 3+ ) salt is reduced to ferrous (Fe 2+ ) salt, it produces a blue colour, the intensity of this can be measured using spectrophotometer (Bhatta et al, 2017). The oxidation state of ferric (Fe 3+ ) salt is similar to that of the radical cation ABTS + (Li et al, 2012).…”

Ferrocenyl–triazole complexes and their use in heavy metal cation sensing

“…[34][35][36][37][38][39] Therefore, ferrocenes are considered invaluable templates as redoxmoieties and in combination with a triazole-heterocyclic derivative can be expected to offer a greater surface area available for the deposition of specic analytes as well as an enhancement in the electron-transfer processes, and consequently, such compounds should stimulate the modied electrodes to behave as multiple signaling molecular selective chemo-sensors for metal cations. 4,5,29,[40][41][42][43][44][45][46][47][48] Herein, we present the synthesis and characterization of diverse ferrocenyl-containing triazole complexes. In addition, their structural and electrochemical properties are reported.…”

A Naphthol and Nitroaniline‐Based Dual‐target Chemosensorfor Fluorometric Sensing of Al3+ and Colorimetric Sensing of Fe3+

“…Moreover, ferric (Fe 3+ ) and ferrous (Fe 2+ ) are important redox pairs in the biology system. Thus, it is necessary to distinguish the two oxidation states to understand the biological system [16–19] …”

“…Thus, it is necessary to distinguish the two oxidation states to understand the biological system. [16][17][18][19] Some analytical methods such as atomic absorption spectroscopy (AAS) and inductively coupled plasma-atomic emission spectrometry (ICP-AES) [20] were used to detect Al 3 + and Fe 3 + . [21,22] However, these methods have disadvantages such as expensive cost, the need for trained operators, and complicated sample preparation.…”