A Cyclam-Based Fluorescent Ligand as a Molecular Beacon for Cu2+ and H2 S Detection (original) (raw)
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Coordination Chemistry Reviews, 2017
Copper(II), Cu 2+ , ion plays not only a fundamental role to sustain important physiological processes in living organisms, but also an important environmental pollutant. A large number of chemosensors that employ the chromogenic, fluorogenic or electrochemical properties of molecules have been reported for selective sensing of copper ions with absorbance and emission in the visible region. Nevertheless, most of these chemosensors for Cu 2+ ions have some limitations including low water-solubility, tedious sample treatment, multistep synthetic routes, or unstable detection signal. Therefore, the challenge in the development of light-up chemosensors which are cost-effective, rapid, facile, biocompatible and applicable to the environmental and biological milieus is still a topical issue. In the context of optical sensing of Cu 2+ ion, the unique features offered by transition metal complexes over organic fluorophores have made them a suitable candidate to monitor Cu 2+ ions in biological systems. Encouraged by the importance of Cu 2+ ions, we herein summarize the recent development of transition metal complexes, particularly those of d 6 or d 10 complexes based on rhenium(I), ruthenium(II), iridium(III), zinc(II) and gold(I) complexes, for optical and electrochemical sensing or biosensing applications of Cu 2+ ion.
Materials advances, 2022
In this work, we developed a simple fluorescent colorimetric chemosensor H 2 L [6,6 0-((1,1 0)-hydrazine-1,2-diylidene bis(methanylylidene)) bis(2-(6-methoxy)) phenol] for rapid detection of Cu 2+ in aqueous solution. The method for synthesis of H 2 L is very simple and environment friendly. This organic Schiff base probe was characterized by 1 H-NMR, FT-IR and ESI-MS spectroscopy along with single-crystal XRD analysis. It exhibited binding-induced colour change with Cu 2+ ion from colourless to intense yellow and fluorescence enhancement. The LOD values of H 2 L towards Cu 2+ were calculated to be 7.1 Â 10 À8 M (colorimetrically) and 3.8 Â 10 À8 M (fluorometrically). The interactions between H 2 L and Cu 2+ were studied by Job's plot, ESI-MS, FT-IR spectroscopy and DFT calculations. The crystal structure of the L-Cu 2+ adduct was also determined by single-crystal X-ray analysis, and it was found that two molecules of L coordinate with three molecules of Cu 2+ ions. The receptor H 2 L could operate in a wide pH range and can be successfully applied for detection and quantification of Cu 2+ ions in environmental samples and logic applications.
A new fluorene derived Schiff-base as a dual selective fluorescent probe for Cu2+ and CN−
Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 2019
A new fluorene based fluorogenic chemosensor, 2-[(9H-Fluoren-2-ylmethylene)-amino]-phenol (L), has been designed, synthesized, and characterized by CHN analyses and different spectroscopic methods. This turn-on fluorogenic chemosensor shows high selectivity and sensitivity toward Cu 2+ and CN¯ with low detection limits of 1.54 × 10-9 M and 1.83 × 10-7 M, respectively. The stoichiometry ratio of L-Cu 2+ in solution is 1:1, by the method of Job's plot and ESI-MS. The microcrystalline solid product of the chemosensor reaction with copper is characterized as CuL 2. The χT value for CuL 2 is temperature independent at a value of 0.403 cm 3 K mol-1 , which is in agreement with a mononuclear copper(II) complex with an isotropic g-value of 2.075. The fluorescence turn-on recognition process for detection of Cu 2+ is attributed to the restricted imine isomerization and blocking of intramolecular charge transfer (ICT) quenching process in the analyte-bound sensor. The selectivity of L for Cu 2+ is based on the chelationenhanced fluorescence effect (CHEF) mechanism. Other interfering ions such as
Sensors and Actuators B: Chemical, 2014
The commercially available 2, 3-diaminophenazine, 1, 2-diamino-anthraquinone and 2, 4dinitrophenylhydrazine (S1-S3) act as a colorimetric, fluorescent probes for selective detection of Cu 2+ ions in aqueous medium over other metal ions. In presence of Cu 2+ , S1 shows fluorescent turn-off by the paramagnetic effect. S2 and S3 with Cu 2+ ions show fluorescent turn-on due to the inhibition of photoinduced electron transfer mechanism. The fluorescent probes S1-S3 detect Cu 2+ ions in aqueous solution at nanomolar levels. Theoretical calculations were employed to understand the sensing mechanism of the sensors towards Cu 2+. S1, S2 and S3 were further applied for biological imaging to confirm that it can be used as a fluorescent probe for monitoring Cu 2+ in living cells, and demonstrated its value in practical applications such as environmental and biological systems.
International Journal of Molecular Sciences
Herein, we have investigated principally with the use of UV and fluorescence (steady-state and time-resolved) spectroscopy the interactions between selected pentapeptides with tyrosine residue (EYHHQ, EHYHQ, EHHQY, and KYHHE) and various metal ions (Cu2+, Mn2+, Co2+, Ni2+, Zn2+, Cr3+, Cd2+, Ag+, Pb2+, Sr2+, Ba2+, Ca2+, Mg2+, Al3+, Fe2+, and Ga3+) in order to establish the relationship between the position of a tyrosine residue in the peptide sequence and the metal ion-binding properties. Among the peptides studied, EHYHQ was evaluated as an efficient and selective ligand for developing a chemosensor for the detection of copper(II) ions. While significant fluorescence emission quenching was observed for that peptide in the presence of Cu2+ cations, other metal cations used at the same and at considerably higher concentrations caused a negligible change of the fluorescence emission spectrum, indicating a high selectivity of EHYHQ for Cu2+ ions. Under optimum conditions, fluorescence i...
Dalton Transactions
A new coumarin-appended thioimidazole-linked imine conjugate, viz. L has been synthesized and characterized. The L has been found to 10 recognize Cu2+ selectively among a wide range of biologically relevant metal ions. The chemosensing behavior of the L has been demonstrated through fluorescence, absorption, visual fluorescent color changes, ESI-MS and 1H NMR titrations. The chemosensor L showed selectivity toward Cu2+ by switch on fluorescence among the metal ions studied with a detection limit of 1.53 μM. The complex formed between L and Cu2+ is found to be 1:1 on the basis of absorption and fluorescence titrations and was confirmed by ESIMS. DFT and TDDFT calculations were performed in order to demonstrate the structure of L and [CuL] and electronic properties of chemosensor L and their copper complex. This highly fluorescent [CuL] complex has been used to recognize sulphide selectively among the other allied anions. Microstructural features of L and its Cu2+ complex have been in...
Cysteine-based fluorescence “turn-on” sensors for Cu2+ and Ag
We designed and synthesized two metal ion binding molecules 3a and 3b based on cysteine. In 3a, pyrene is used as a fluorescent probe, while 3b contains tryptophan, which acts as a fluorescent probe as well as facilitates metal ion binding. Detailed spectroscopic, calorimetric, microscopic and computational studies revealed the binding mode and the plausible structures of the complexes.
Materials Technology, 2011
Copper is one of the essential trace nutrients in biological systems. Apart from its biological role, copper is predominantly being used in ceramics, alloys, household utensils, electrical wires, fertiliser preparation and in various engineering purposes, owing to its high malleability, electrical conductivity and antibacterial activity. Such widespread use leads to accumulation of copper in the environment, which subsequently gets into the human body. Therefore, environmental and biological detection of copper is necessary to assess its concentration levels. We have developed 4-(diethylamino)-salicylaldehyde rhodamine hydrazone ligand 1 as a naked eye chemosensor for Cu 2z with enhanced turn-on fluorescence emission in the longer wavelength region that works even in aqueous media. The observed turn-on colourimetric and fluorescence emission upon binding of ligand 1 to Cu 2z was attributed to the ring opening of spirolactam moiety and the strong coordination ability of ring opened form to the copper(II) ion. Ligand 1 can be readily used for the environmental as well as biological detection of Cu 2z , owing to excitation and fluorescence emission in the longer wavelength region, vomiting adverse effects of ultraviolet radiation as observed with most of the reported chemosensors for Cu 2z .