New Pyridine-Bridged Ferrocene–Rhodamine Receptor for the Multifeature Detection of Hg²⁺ in Water and Living Cells

Abstract

A challenge in the design of optical and redox-active receptors is how to combine a specific recognition center with an efficient responsive system to facilely achieve multifeature detection in biological and environmental analyses. Herein, a novel ferrocene–rhodamine receptor conjugated with a pyridine bridge was designed and synthesized. This receptor can sensitively sense Hg 2+ in aqueous media via chromogenic, fluorogenic, and electrochemical multisignal outputs with a low detection limit and fast response time. Moreover, it can be qualified as a fluorescent probe for effectively monitoring Hg 2+ in living cells. A plausible recognition mode was proposed and rationalized with theoretical calculations.

An activatable near-infrared hemicyanine-based probe for selective detection and imaging of Hg2+ in living cells and animals

“…To verify the successful synthesis of the probe CyP, all products were characterized by NMR and HR-MS. 1 H NMR, 13 C NMR, 31 P NMR and the molecular ion peak at 628.2432 in HR-MS spectra revealed the successful synthesis of the probe CyP (Fig. S1-S11 †).…”

“…The mercury ion (Hg 2+ ), a hazardous heavy metal ion, has substantial toxicity and is harmful to human health. [1][2][3][4][5] It can cause serious irreversible damage by binding to the thiols of enzymes, proteins and even DNA in living systems. [6][7][8] Hg 2+ mainly accumulates in the kidneys and liver and causes serious illness such as motor and cognitive impairment, pink disease, nerve damage and the famous Minamata disease.…”

Similar, Yet Different: Long-Range Metal–Metal Coupling and Electron-Transfer Processes in Metal-Free 5,10,15,20-Tetra(ruthenocenyl)porphyrin

“…The reaction mixture was kept in the dark and under a nitrogen atmosphere for 20 h. After this period, 110 mg of pchloranil (4 mmol) was added and the mixture was refluxed for 1 h. The solution was cooled down, concentrated, and purified by column chromatography on basic Al 2 O 3 using THF as the eluent to afford 134 mg of a fine green powder for a 66% yield (mp > 250°C). 1 H NMR (benzene-d 6 ): δ(ppm) 9.80 (s, 8H, β-pyrrole), 5.66 (t, 8H, α in substituted Cp), 4,89 (t, 8H, β in substituted Cp) 4.37 (s, 20H, Cp), −0.48 (br s, 2H, internal NH). 13 C NMR (benzene-d 6 ): δ(ppm) 130.60 (β-pyrrole), 115.91 (C-meso), 94.14 (C-ipso), 80.26 (α in substituted Cp), 72.96 (Cp), 71.35…”

“…Similar to ferrocenyl analogues, 106 these compounds revealed an aromatic or an antiaromatic character, 107 suggesting the transmission of π-electron conjugation across the ruthenium d-orbitals. As fundamental proof for this feature, the authors induced the switching of the ring current sign (determined through 1 H NMR experiments) after the formal two-electron reduction of the macrocycle. All of the examples shown in Figure 1 have a single ruthenocene group appended to the porphyrinoid, and thus, the long-range metal−metal coupling between ruthenocenyl fragments in porphyrinoids has never been addressed.…”

“…Metallocene-containing compounds were intensively studied because of their potential application in redox-driven fluorescent imaging, − medicine, − light harvesting, − and molecular electronics. − In addition, poly­(metallocenyl)-containing systems were investigated as platforms for the fundamental understanding of metal–metal (including long-range) coupling, electron migration, and solvent/electrolyte-dependent charge-stabilization properties of the mixed-valence states that are critical, for instance, for cellular quantum automata. − …”