A Selective Colorimetric and Fluorescent Chemodosimeter for Fe(III) Ion Based on Hydrolysis of Schiff Base

An efficient colorimetric and fluorescent chemodosimeter for Fe³⁺ ions has been developed. The visual and fluorescent behaviors of the receptor toward various metal ions were investigated. The receptor shows exclusive response toward Fe³⁺ ions and also distinguishes Fe³⁺ from other cations by color change and unusual fluorescence enhancement in aqueous solution (DMSO/H₂O = 4/1, v/v). Thus, the receptor can be used as a colorimetric and fluorescent sensor for the determination of Fe³⁺ ion. The visual color detection limit and the fluorescence detection limit of the receptor towards Fe³⁺ are (1.42 ± 0.01) × 10^‐6 M and (7.57 ± 0.04) × 10^‐8 M, respectively. The fluorescence microscopy experiments showed that the receptor is efficient for detection of Fe³⁺ in vitro, developing a good image of the biological organelles. The sensing mechanism is proven to be a hydrolysis process     

A Highly Selective and Sensitive Fluorescent Chemosensor for Detection of Al3+ in Totally Aqueous Media

A fluorescent chemosensor ( 1 ) based on 2‐hydroxy‐1‐naphthaldehyde Schiff‐base was developed for the detection of Al³⁺ in 100% aqueous solution. Upon addition of Al³⁺, a significant fluorescence enhancement was observed, which was not affected by other metal ions including Na⁺, K⁺, Ca²⁺, Mg²⁺, Mn²⁺, Co²⁺, Ni²⁺, Cu²⁺, Cr³⁺, Ag⁺, Pb²⁺, Zn²⁺, Cd²⁺, Hg²⁺, Fe²⁺ and Fe³⁺ under weak acid conditions. Moreover, the specific response to Al³⁺ was visible under natural light. The binding mode between 1 and Al³⁺ was clarified by ESI‐MS and ¹H NMR.     

A New Tridentate Sulfur Receptor as a Highly Sensitive and Selective Fluorescent Sensor for Cu2+ Ions

The introduction of Lawesson′s reagent into a bis‐rhodamine spirolactam system afforded a new fluorescent sensor for Cu²⁺ ions, SRR , which contained a new tridentate sulfur ligand. SRR showed excellent specificity for Cu²⁺ ions over other cations (including Cu⁺, Hg²⁺, and Fe³⁺), very high sensitivity (10 nM ), and a rapid response time (3 min). The detection mechanism was investigated by ¹H NMR, ¹³C NMR, ³¹P NMR, and ESR spectroscopy, MS, and Gaussian calculations. Coordination of a Cu²⁺ ion to the tridentate sulfur ligand, which promotes ring‐opening of the rhodamine groups, followed by a spontaneous reduction reaction (Cu²⁺ into Cu⁺), has been proposed as the sensing mechanism.     

New Cr,Mo, W,and Fe Metal Complexes with Potentially Heptadentate (S3N4) Tripodal Schiff Base Ligand: Synthesis,Characterization, and Antibacterial Activity

Russian Journal of General Chemistry - Reactions of Cr, Mo, W, and Fe metal carbonyls with potentially heptadentate (S3N4) tripodal Schiff base ligand, (thio)3tren, have been studied. The Schiff...     

A Highly Selective and Turn‐on Fluorescent Probe for Fe3+ Ion Based on Perylene Tetracarboxylic Diimide

We have demonstrated a turn‐on fluorescent sensor 6 for detection of Fe³⁺ based on photo‐induced electron transfer (PET) mechanism. The probe comprises a perylene tetracarboxylic diimide (PDI) fluorophore and two bis((1,2,3‐triazol‐4‐yl)methyl)amine (DTA) moieties as the metal ion receptors. It exhibits high selectivity toward Fe³⁺ over various other metal ions in CH₃CN/H₂O (1:1, V/V). The binding stoichiometry for 6 ‐Fe³⁺ complexes has been determined to be 1:2 by a Job plot of fluorescence. The association constant between 6 and Fe³⁺ was estimated to be 1.04×10¹⁰ (mol/L)^?2 by Benesi‐Hildebrand equation.     

Two New 3D Metal-Organic Frameworks Constructed by Polycarboxylate and N-Donor Ligands: Crystal Structure,Photocatalytic Performances,and DFT Calculation

Russian Journal of Coordination Chemistry - Two new metal-organic frameworks, [Zn(Bdc)(Bip)?H2O] (I) and {[Cd2(Btc)2(H2O)2](H2Bib)· 6H2O} (II) (H2Bdc = 1,3-benzenedicarboxylic acid,...     

改性PAN纤维与Fe3+的配位反应及配合物的催化性能

采用盐酸羟胺和水合肼的混合物分别对PAN纤维进行改性制备了偕胺肟改性PAN纤维(AO-PAN)和混合改性PAN纤维(M-PAN), 并分别与Fe³⁺进行配位反应生成两种改性PAN纤维铁配合物(Fe-AO-PAN和Fe-M-PAN). 研究了配位反应的动力学特性及温度和Fe³⁺初始浓度的影响, 并采用DRS和ESR技术比较了两种不同改性PAN纤维铁配合物对偶氮染料活性红195氧化降解反应的催化性能. 结果表明, 在所设定的温度和浓度范围内, 两种改性PAN纤维与Fe³⁺之间的配位反应平衡符合Langmuir 和Freundlich 吸附等温模型以及Lagergren准二级动力学方程, 并且AO-PAN比M-PAN更容易与Fe³⁺发生配位反应. 在相同条件下AO-PAN与Fe³⁺反应的配合量和反应速率常数均比M-PAN与Fe³⁺反应的高. 两种配合物对染料的氧化降解反应具有催化作用, 暗态条件下Fe-M-PAN比Fe-AO-PAN表现出更高的催化活性, 而光辐射条件下Fe-AO-PAN的催化活性显著增强.     

1-对氯苯基-3-苯基-4-苯甲酰基-吡唑啉酮-5缩胺类席夫碱铜配合物的合成与抑菌活性

合成了7种新型酰基吡唑啉酮席夫碱过渡金属铜配合物.7种席夫碱分别为:1-对氯苯基-3-苯基-4-苯甲酰基-吡唑啉酮-5缩苯胺(HS1)、对氯苯胺(HS2)、对溴苯胺(HS3)、糠胺(HS4)、对甲氧苯胺(HS5)、对乙氧苯胺(HS6)和萘胺(HS7)席夫碱.由元素分析、络合滴定法、质谱和摩尔电导值确定配合物的组成通式为[Cu(S)2](S=S1,S2,S3,S4,S5,S6,S7),通过红外光谱、热重谱、核磁共振氢谱和液相色谱-质谱联用技术对配体及配合物的结构进行了表征,同时对7个席夫碱配体及其7个铜配合物的抑菌活性进行了初步研究.表征结果表明:在不同的测试条件下,7个配体的异构体存在方式不同.配位时酮式结构可能转化为烯醇式结构,按去质子方式以烯醇氧负离子和亚胺基氮原子双齿形式与铜中心离子成键.抑菌实验结果显示:所有化合物对受试的4个菌种均有不同程度的抑菌活性,其中配合物普遍强于配体.抑菌能力呈现浓度效应,在浓度为3.0mg·mL-1时最大直径可达16.0mm.     

A Novel Ratiometric Fluorescent Probe for Highly Sensitive and Selective Detection of β‐Galactosidase in Living Cells

β‐Galactosidase, a glycoside hydrolase enzyme, has been proved to be an important biomarker of cell senescence and primary ovarian cancer. Effective detection of β‐galactosidase has attracted wide attention. Herein, one ratiometric fluorescent probe has been successfully synthesized for detecting the β‐galactosidase in living cells. The as‐prepared probe exhibits two emission peaks at 490 nm and 530 nm, respectively, and the ratio of fluorescence intensities from the two emission peaks could be utilized to monitor the β‐galactosidase. This present ratiometric fluorescent probe is, therefore, very promising for effective, sensitive, and selective detection of the β‐galactosidase in living cells.     

A Zn(II)-Based Sql Type 2D Coordination Polymer as a Highly Sensitive and Selective Turn-On Fluorescent Probe for Al3+

A luminescent coordination polymer with the overall formula {[Zn(tr₂btd)(bpdc)]∙DMF}_n (where tr₂btd = 4,7-di(1H-1,2,4-triazol-1-yl)-2,1,3-benzothiadiazole; bpdc = 4,4′-biphenyldicarboxylate) was synthesized and characterized by single-crystal and powder X-ray diffraction, thermogravimetric, infrared spectroscopy, and elemental analyses. Luminescent properties of the obtained compound were studied in detail both in the solid state and as a suspension in N,N-dimethylacetamide (DMA). It was found that {[Zn(tr₂btd)(bpdc)]∙DMF}_n exhibits bright turquoise luminescence with excellent quantum efficiency and demonstrates turn-on fluorescence enhancement effect upon soaking in DMA Al³⁺ solution. Fluorescence titration experiments were carried out and the detection limit for Al³⁺ ions was calculated to be 120 nM, which is among the lowest reported values for similar materials. Moreover, compound demonstrated excellent selectivity and reusability, and the mechanism of the response is discussed. These results indicate that {[Zn(tr₂btd)(bpdc)]∙DMF}_n is a promising probe for sensitive fluorescent Al³⁺ detection.     

A Water‐Stable Uranyl Organic Framework as a Highly Selective and Sensitive Bifunctional Luminescent Probe for Fe3+ and Tetracycline Hydrochloride

A new coordination polymer (H₂bpy)_0.5?[(UO₂)_1.5(ipa)₂(H₂O)] ( 1 ) (H₂ipa=isophthalic acid, bpy=4,4′‐bipyridine) was synthesized by hydrothermal condition. It was characterized by IR spectroscopy, elemental analysis, TG‐DTA analysis, and powder X‐ray diffraction. Analysis of single‐crystal X‐ray diffraction results showed that the title compound exhibited a double chain bridged by the different uranyl ions and ipa^2? ligands. Through the hydrogen bond interactions and π???π stacking interactions, the double chains were assembled into the three‐dimensional supramolecular framework. Furthermore, the compound can be used as a promising bifunctional luminescence sensor for detecting and identifying Fe³⁺ and tetracycline hydrochloride antibiotic molecules with high selectivity and sensitivity in aqueous solutions. Moreover, the luminescent sensing mechanisms for different analytes were proposed. Moreover, the electronic properties of title compound were explored by density functional theory (DFT) calculations. The sensor system has been successfully applied for the detection of Fe³⁺ and tetracycline hydrochloride with high recovery percentages and low relative standard deviation in real river water samples.     

A Sensitive and Selective Fluorescent Probe for Cysteine Based on a New Response‐Assisted Electrostatic Attraction Strategy: The Role of Spatial Charge Configuration

A new strategy for fast fluorescent detection of cysteine (Cys), based on a response‐assisted electrostatic attraction, is demonstrated. By utilizing this strategy, we designed and synthesized three fluorescent probes for the specific detection of Cys under actual physiological conditions. The probe m‐ CP , a coumarin fluorophore conjugated with a substituted methyl pyridinium group through an unsaturated ketone unit, showed highly selective and sensitive detection for cysteine (Cys) over homocysteine (Hcy) and glutathione (GSH). The kinetic analysis indicated that the sensing process was highly accelerated (a response time less than 1 min) by the response‐assisted electrostatic attraction. More importantly, control experiments with isomeric probes first demonstrated that the spatial charge configuration of the probe played an important role in Cys‐preferred selectivity and kinetic rate acceleration. Furthermore, the practical utility of the probe m‐ CP in the fluorescent labeling of Cys residues within proteins was demonstrated. Finally, these probes were employed in living cell imaging with HeLa cells, in which it displayed satisfactory cell permeability and enabled us to distinguish active thiols in the cytoplasm, nucleus, and mitochondria.     

两种磺酰胺类化合物的合成及其对Fe3+的氧化-还原荧光“开-关”性质

合成了两种磺酰胺类化合物, 并研究了其荧光性能. 通过它们对金属阳离子的选择性识别实验, 发现其在乙醇水溶液中均对Fe3+有专一性的识别作用, 并在NH2OH·HCl和H2O2的存在下, 两种化合物对Fe3+都具有氧化-还原荧光“开-关”作用.     

Azomethine-H as a Highly Selective Fluorescent Probe for Fe3+ Detection in 100％ Aqueous Solution and Its Application in Living Cell Imaging

A simple assay for the detection of Fe³⁺ in water by means of fluorescence spectroscopy was developed based on a commercially available reagent, Azomethine-H(A-H), allowing sensing trace levels of Fe³⁺ with high selectivity over other cations. A significant fluorescence quenching of A-H at 424 nm was found after its binding with Fe³⁺ in 100% aqueous solution at pH=7.0, while other physiologically relevant metal ions posed little interference. The fluorescence responses can be well described by the modified Stern-Volmer equation. A good linear relationship(R²=0.9904) was observed up to 1.6×10^-5 mol/L Fe³⁺ ions. The detection limit, calculated via the 3σ IUPAC(international union of pure and applied chemistry) criteria, was 1.95×10^-7 mol/L. Moreover, the colorimetric and fluorescent response of A-H to Fe³⁺ can be conveniently detected by the naked eye, providing a facile method for visual detection of Fe³⁺. The proposed method was used to determine Fe³⁺ in water samples. Moreover, inverted fluorescence microscopy imaging using human umbilical vein endothelial cells shows that A-H can be used as an effective fluorescent probe for detecting Fe³⁺ in living cells.     

A Stimuli‐Responsive Nanogel‐Based Sensitive and Selective Fluorescent Sensor for Cr3+ with Thermo‐Induced Tunable Detection Sensitivity

Stimuli‐responsive poly(N‐isopropylacrylamide) nanogel with covalently labeled rhodamine B urea derivatives (P(NIPAM‐co‐RhBUA)) is utilized as a sensitive fluorescent probe for Cr³⁺ in aqueous solution, and its thermo‐induced tunable detection capacity is investigated. At 20 °C, non‐fluorescent nanogel can selectively bind with Cr³⁺ over some other metal ions, leading to prominent fluorescence OFF–ON switching due to the recognition of RhBUA with Cr³⁺. Upon heating above the phase transition temperature, enhanced fluorescence intensity is observed (≈61‐fold increase at 45 °C) for the nanogel in the presence of Cr³⁺, accompanied with an improved detection sensitivity, which suggest that hydrophobic microenvironment generated in the collapsed nanogel plays an active role for their detection performance.

     

Fe3O4@SiO2/Schiff base complex of metal ions as an efficient and recyclable nanocatalyst for the green synthesis of quinoxaline derivatives

Fe₃O₄@SiO₂/Schiff base complex of metal ions catalyzed the reaction between phenylene-1,2-diamines and 1,2-diketones to produce quinoxalines in aqueous media at room temperature. This eco-friendly method provides several advantages such as mild reaction conditions, good to excellent yields, simple work-up, and nanocatalyst stability. Also, nanocatalyst can be simply recovered by a magnetic field and reused for at least five successive reactions.     

Copper Schiff base complex immobilized on silica‐coated Fe3O4 nanoparticles: a recoverable and efficient catalyst for synthesis of polysubstituted pyrroles

In this work, a copper Schiff base complex immobilized on silica‐coated Fe₃O₄ nanoparticles is synthesized, and studied as a highly efficient, recyclable, green and heterogeneous catalyst for the preparation of polysubstituted pyrroles under solvent‐free and mild conditions. This new catalyst was characterized by different techniques, such as Fourier transform infrared (FT‐IR), X‐ray powder diffraction (XRD), field‐emission scanning electron microscopy (SEM), energy‐dispersive X‐ray spectroscopy (EDX), inductively coupled plasma (ICP) and vibrating sample magnetometry (VSM). The simple and environmentally one‐pot multicomponent condensation of nitromethane, an aryl aldehyde, a 1,3‐dicarbonyl compound and an amine in the presence of above catalyst affords the title compounds at room temperature. At the end, we compared the results for the synthesis of polysubstituted pyrroles in the presence of our nanocatalyst with previously reported catalysts in the literature.     

Application of novel and reusable Fe3O4@CoII(macrocyclic Schiff base ligand) for multicomponent reactions of highly substituted thiopyridine and 4H-chromene derivatives

In this research study we designed and synthesized Co^II(macrocyclic Schiff base ligand containing 1,4-diazepane) immobilized on Fe₃O₄ nanoparticles as a novel, recyclable, and heterogeneous catalyst. The nanomaterial was fully characterized using various techniques such as Fourier-transform infrared spectroscopy, scanning electron microscopy, transmission electron microscopy, X-ray diffraction, energy-dispersiveX-ray spectroscopy, thermogravimetric analysis, vibrating sample magnetometry, differential reflectance spectroscopy, Brunauere–Emmette–Teller method, inductively coupled plasma, and elemental analysis (CHNS). Then, the catalytic performance was successfully investigated in the multicomponent synthesis of 2-amino-4-aryl-6-(phenylsulfanyl)pyridine-3,5-dicarbonitrile and 2-amino-5,10-dioxo-4-aryl-5,10-dihydro-4H-benzo[g]chromene-3-carbonitrile derivatives. Furthermore, the catalyst was isolated using a simple filtration, and recovery of the nanocatalyst was demonstrated five times without any loss of activity.     

Synthesis and In Vitro Anti-HIV Activity of Some New Schiff Base Ligands Derived from 5-Amino-4-phenyl-4H-1,2,4-triazole-3-thiol and Their Metal Complexes

New Schiff base ligands (6–9) derived from 5-amino-4-phenyl-4H-1,2,4-triazole-3-thiol 1 and substituted benzaldehydes (2–5) as well as their metal complexes with Cu(II), Fe(II), Au(III), and Mn(II) (12–17) have been synthesized. A new benzothiazole derivative (11) was prepared from coupling of 7 with N-(benzothiazol-2-yl)-2-chloroacetamide 10. Their spectral properties were investigated. The newly designed and synthesized Schiff base ligands and the metal complexes were assayed for anti-HIV-1 and HIV-2 activity by examination of their inhibition of HIV-induced cytopathogenicity in MT-4 cells. Compounds 11 and 16 were found to be the most active inhibitors in cell culture (EC₅₀ = 12.2 μg/mL (SI = 4) and > 2.11 μg/mL (SI = > 1), respectively) against HIV-1, whereas 11 showed inhibition against HIV-2 of EC₅₀ > 10.2 μg/mL with SI = 9, which provided a good lead for further optimization.     

Synthesis and X-Ray Crystal Structure of New Oxathiacrown Ethers Containing Sulfoxide Group and Their Metal-Binding Properties: Highly Selective Receptors for Ag+ and Cu2+

Three new oxathiacrown ethers 1, 2 and 3 containing a sulfoxide group were synthesized in a simple way. Conductometric titration studies in pure acetonitrile were employed to invistigate their binding affinities towards Ag ⁺, Cu ²⁺, Pb ²⁺, Cd ²⁺, Zn ²⁺, Co ²⁺, Ni ²⁺, Cr ³⁺and Hg ²⁺. They were found to be selective for Ag ⁺ and Cu ²⁺ over the other metals investigated. Ligand 1 has the highest selectivity towards Ag ⁺. The structure of compound 3 was confirmed by X-ray crystallography.Supplementary Data relevant to this article have been deposited at the Cambridge Crystallographic Data Centre under the deposition number 232076.