Novel Rhodamine-Derivated Dual-Responsive Colorimetric Fluorescent Chemoprobe for the Hypersensitive Detection of Ga³⁺ and Hg²⁺ and Biological Imaging

Abstract

A unique rhodamine-based derivative, 2-amino-3-(((1E,2E)-2-((3′,6′-bis­(diethylamino)-3-oxospiro­[isoindoline-1,9′-xanthen]-2-yl)­imino)­ethylidene)­amino)­maleonitrile (RhGDM), was easily fabricated just by Schiff-base condensation. RhGDM displays superb selectivity and sensitivity for specifically detecting the biologically and ecologically important Ga3+ and Hg2+ cations via a fluorescence “off–on” type in aqueous medium with high quantum yields and also the ultralow detection limits down to nanomolar level, which are far below the maximum permissible dosage values set by the WHO, indicating high efficiency and reliability of the chemoprobe. Meanwhile, RhGDM exhibits Hg2+-selective chromogenic behavior, and Hg2+ can be detected by naked eye. Interestingly, the plausible sensing mechanism is the aforementioned metal cation-promoted hydrolysis of the rhodamine-based Schiff-base skeleton, which was confirmed by the mass spectra, IR spectra, and density functional theory calculations as well as the irreversibilities of fluorescence signals in the corresponding reaction systems, and it is the first reported smart chemoprobe capable of recognizing simultaneously Ga3+ and Hg2+ through the hydrolytic mode to the best of our knowledge. Notably, the analytical applicability of RhGDM can be further realized by using paper films and silica-coated slides. More excitingly, RhGDM was successfully employed in tracing out the intracellular Ga3+ and Hg2+ cations in living cells.

A Bifunctional “Off‐On” Fluorescence Probe Based on Naphthalene for the Detection of Ag+ and Al3+ and Its Application in Practical Water Samples, as a Logic gate and as Test Paper

“…[1,[39][40][41] Similarly, 1 H NMR spectra of PCT and PCT-Al [42][43][44][45] The signals of H 10 split from a single peak into double peaks as a result of the imino N atom coordinated with Al 3 + , which limited the rotation of C=N and the chelation of PCT and Al 3 + forming two stable sixmembered ring structures. [46][47][48] The possible mechanism of sensing Ag + and Al 3 + is described in Scheme 1. The Schiff base N atom contributed to the photo-induced electron transfer (PET) phenomenon, which quenched the fluorescence of PCT.…”

Modulating the Sensing Behavior of Functionalized Mesoporous Silica towards Metal Ions in Aqueous Medium

“…There are reports on the effects of various substitutions on rhodamine platforms on metal ion sensing properties. [31][32][33][34][35][36] Based on those background, in this work the linkage between the bisphenol A (Compound A) and rhodamine 6G (Compound B) derivative (Scheme 1) has been changed from hydrazine [30] to ethylene diamine unit to obtain RBA-IMS and the effect of this change on the sensing and separation properties has been investigated. And indeed, it was found to have a great effect on the sensing behavior of the resulting probe.…”

“…It showed Al 3+ , Cr 3+ , Fe 3+ and Cu 2+ sensing in ethanol while in water it could detect and separate Cu 2+ and Hg 2+ ions. There are reports on the effects of various substitutions on rhodamine platforms on metal ion sensing properties [31–36] . Based on those background, in this work the linkage between the bisphenol A ( Compound A ) and rhodamine 6G ( Compound B ) derivative (Scheme 1) has been changed from hydrazine [30] to ethylene diamine unit to obtain RBA‐IMS and the effect of this change on the sensing and separation properties has been investigated.…”

An α-naphtholphthalein-derived colorimetric fluorescent chemoprobe for the portable and visualized monitoring of Hg2+by the hydrolysis mechanism

“…60 Whereas, thus far there are few DAMN-derived fluorescent chemoprobes for the specific detection of Hg 2+ , particularly by the hydrolysis mode, that have been reported. [61][62][63][64] Unfortunately, the previous works have shown that the single DAMN-based fluorescent chemoprobes can routinely detect Al 3+ instead of Hg 2+ . 65,66 Fortunately, Serkan Erdemir et al have reported a bistructure chemoprobe based on a fluorescein-phenolphthalein hybrid for the dual-channel fluorescent detection of Hg 2+ and Zn 2+ .…”