Nitrogen and sulfur co-doped carbon dot-based ratiometric fluorescent probe for Zn2+ sensing and imaging in living cells

A near-infrared nitrogen and sulfur co-doped carbon dot (N,S-CD)-based ratiometric fluorescent probe is proposed that is synthesized via hydrothermal approach using glutathione and formamide as precursor for sensing and imaging of Zn²⁺. The prepared N,S-CDs facilitate binding with Zn²⁺ owing to N and S atom doping. The ratio (I₆₅₀/I₆₈₀) of fluorescence intensity at 650 nm and 680 nm increased with the concentrations of Zn²⁺ when the excitation wavelength was 415 nm. The linearity range was 0.01 to 1.0 μM Zn²⁺with a detection limit of 5.0 nM Zn²⁺. The proposed probe was applied to label-free monitoring of Zn²⁺ in real samples and fluorescent imaging of Zn²⁺ in living cells, which confirmed its promising applications.

Cu2+ -selective naked-eye 'off-on' fluorescent probe with multisignals: chromaticity, fluorescence, electrochemistry

In this study, a rhodamine-acetylferrocene conjugate of RBFc was synthesized and then characterized using spectroscopy and single-crystal analysis. The chemosensor RBFc exhibited a marked colour change from colourless to pink after binding to Cu²⁺ ions. Importantly, under the presence of the other competing cations in aqueous solution, only Cu²⁺ ions caused spirolactam ring opening in rhodamine B in RBFc, resulting in an enhanced absorbance of ultraviolet light spectra and fluorescence spectra, as well as obvious shifts in cyclic voltammetry curves and differential pulsed voltammetry curves. The novel probe described in this manuscript provides an attractive approach for detecting Cu²⁺ in the presence of other multisignals.

Novel rhodamine-based colorimetric and fluorescent sensor for the dual-channel detection of Cu2+ and Co2+/trivalent metal ions and its AIRE activities

A rhodamine hydrazone 1 bearing coumarin moiety was designed and prepared. Compound 1 exhibited high selectivity toward Co²⁺ and trivalent metal ions with fluorescence enhancement in CH₃OH solution. However, 1 selectively responded to Al³⁺ in nearly pure H₂O media and was further applied to monitor Al³⁺ in live cells. Moreover, 1 could also act as a colorimetric probe toward Cu²⁺ in either CH₃OH or H₂O solution. In addition, sensor 1 displayed aggregation-induced ratiometric emission (AIRE) activities in mixed H₂O/CH₃OH solution.

A cationic tetrahedral Zn(ii) cluster based on a new salicylamide imine multidentate ligand: synthesis, structure and fluorescence sensing study

We present here a monocationic Zn^II tetrahedral cluster which is extremely stable and exhibits highly sensitive and selective recognition of phosphates against other common anions in water containing media.

Investigation of the formation of the [2(iohexol) + Mg]2+ complex and its fragmentation in electrospray ionization tandem mass spectrometry

RATIONALE

Mass spectrometry has been developed as one of the common tools for the analysis of the organometallic systems in the gas phase over decades. The study of the fragmentation of organics-metal complexes has attracted much attention since the interesting dissociation pathways exhibited by these compounds are usually different from the protonated analogues.

METHODS

In this work, iohexol complexed with different dications such as Mg²⁺ , Cu²⁺ and Zn²⁺ have been investigated by electrospray ionization (ESI) tandem mass spectrometry. Additionally, deuterium-labeling experiments and an analogue of iohexol were utilized to confirm the reaction mechanisms. A computational chemistry method was used to identify the coordination conformation between iohexol and metal ions in the gas phase. UV detection was also used to identify the interaction between iohexol and metal ions in the liquid phase.

RESULTS

A special gas-phase open-loop reaction of iohexol induced by Mg²⁺ , leading to the formation of [iohexol + Mg - H - HI - C₃ H₄ O]⁺ , was observed in the collision-induced dissociation of [2(iohexol) + Mg]²⁺ complexes. Moreover, theoretical calculation shows the proposed coordination configuration of iohexol/Mg²⁺ complexes. The Mg²⁺ could have tetrahedral coordination with two iohexol molecules.

CONCLUSIONS

The percent study is a case for better understanding the formation of a typical organic/metal complex and its gas-phase fragmentation reaction. In addition, it provides useful information for researchers working on analysis or structural elucidation of complicated compounds which contain the iohexol analogues. Copyright © 2016 John Wiley & Sons, Ltd.

Rhodamine-modified upconversion nanoprobe for distinguishing Cu2+ from Hg2+ and live cell imaging

A new organic–inorganic hybrid nanoprobe based on luminescence resonance energy transfer (LRET) from mesoporous silica coated upconversion nanoparticles to a rhodamine B derivative was prepared for distinguishing Cu²⁺ from Hg²⁺ and live cell imaging applications.

Facile rhodamine-based colorimetric sensors for sequential detections of Cu(ii) ions and pyrophosphate (P2O74−) anions

Two rhodamine hydrazine derivatives Rh1 and Rh2 with catechol and ether functionalities have been synthesized and utilized towards sequential colorimetric detections of Cu(ii) and pyrophosphate (PPi) ions in a semi-aqueous medium.

High contrast off–on fluorescence photo-switching via copper ion recognition, trans–cis isomerization and ring closure of a thiosemicarbazide Schiff base

Two independently addressable photochromic systems based on distinct mechanisms and selective recognition for Cu²⁺were investigated in detail.

Dipicolylamine coupled rhodamine dyes: new clefts for highly selective naked eye sensing of Cu2+and CN−ions

The dipicolylamine (DPA) motif has been utilized in devising rhodamine labeled compounds1and2for Cu²⁺ions.

A sandwich-type zinc complex from a rhodamine dye based ligand: a potential fluorescent chemosensor for acetate in human blood plasma and a molecular logic gate with INHIBIT function

Zn-R1 exhibits reversible binding with acetate yielding different optical and fluorescence outputs on alternate addition of zinc and acetate ions.

1,8-Naphthyridine-based molecular clips for off–on fluorescence sensing of Zn2+ in living cells

New 1,8-naphthyridine-based clip-like receptor as “off–on” fluorescent probe was designed and synthesised for selectively sensing Zn²⁺ in living cells.