A Schiff base-based fluorescent probe for the quick detection of ClO− ions

2020 ◽  
Vol 98 (8) ◽  
pp. 403-407
Author(s):  
Min Zhang ◽  
Tao Hu ◽  
Changyan Sun ◽  
Wenjun Li ◽  
Zhidong Chang
Keyword(s):  
Schiff Base ◽  
Fast Response ◽  
Ionization Mass ◽  
X Ray Diffraction ◽  
Detection Mechanism ◽  
Esi Ms ◽  
Wide Ph Range ◽  
Nuclear Magnetic Resonance Spectrometry ◽  
Magnetic Resonance Spectrometry ◽  
Ph Range

A new Schiff base 2-hydroxy-5-[(2,7-dihydroxy-1-naphthyl)methylideneamino]benzoic acid (HNMB) has been designed and synthesized. HNMB was characterized by Fourier-transform infrared spectroscopy (FTIR), electrospray ionization mass spectrometry (ESI–MS), nuclear magnetic resonance spectrometry (NMR), and single crystal X-ray diffraction. Fluorescence spectra show that HNMB could be used as a “turn-on” probe to detect ClO− ions from other anions in DMSO/H2O (v/v = 1:1) with a fast response time of 10 s and a low detection limit of 3.6 × 10−7 mol/L. Moreover, the probe could work in a wide pH range of 4–10. The detection mechanism was studied by ESI–MS.

Rapid Recognition of Fatal Cyanide in Water in a Wide pH Range by a Trifluoroacetamido Based Metal-Organic Framework

2021 ◽  
Author(s):  
Abhijeet Rana ◽  
Chiranjib Gogoi ◽  
Subhrajyoti Ghosh ◽  
Soutick Nandi ◽  
Saurav Kumar ◽  
...  
Keyword(s):  
Thermogravimetric Analysis ◽  
Terephthalic Acid ◽  
Metal Organic Framework ◽  
X Ray Diffraction ◽  
X Ray ◽  
Acid Ligand ◽  
Wide Ph Range ◽  
Metal Organic ◽  
Ph Range ◽  
Organic Framework

A new metal-organic-framework (MOF) called UiO-66-NH-COCF3 was prepared using trifluoroacetamido functionalized terephthalic acid ligand. Powder X-ray diffraction (PXRD), infrared (IR) spectroscopy, thermogravimetric analysis (TGA) and Brunauer Emmett-Teller (BET) experiment were...

scholarly journals Facile Production of a Fenton-Like Photocatalyst by Two-Step Calcination with a Broad pH Adaptability

Nanomaterials ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 676
Author(s):  
Siyang Ji ◽  
Yanling Yang ◽  
Xing Li ◽  
Hang Liu ◽  
Zhiwei Zhou
Keyword(s):  
Rhodamine B ◽  
Photoelectron Spectroscopy ◽  
Active Oxygen Species ◽  
Oxygen Species ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Wide Ph Range ◽  
Calcination Method ◽  
Ph Range

A novel heterogeneous Fenton-like photocatalyst, Fe-doped graphitic carbon nitride (Fe-g-C3N4), was produced by facile two-step calcination method. This Fe–g–C3N4 catalyzed rhodamine B degradation in the presence of H2O2 accompanied with visible light irradiation. transmission electron microscopy(TEM), x-ray diffraction (XRD), FT-IR, x-ray photoelectron spectroscopy (XPS), and photoluminescence fluorescent spectrometer (PL) characterization analysis methods were adopted to evaluate the physicochemical property of samples. It can be observed that the Fe-g-C3N4 exhibited excellent photocatalytic Fenton-like activity at a wide pH range of 3–9, with rhodamine B(RhB) degradation efficiency up to 95.5% after irradiation for 45 min in the presence of 1.0 mM H2O2. Its high activity was ascribed to the formation of Fe–N ligands in the triazine rings that accelerated electron movement driving the Fe(III)/Fe(II) redox cycle, and inhibited photo-generated electron hole re-combinations for continuous generation of reactive oxygen species by reactions between Fe(II) and H2O2. The main active oxygen species were hydroxyl radicals, followed by superoxide radicals and hole electrons. This produced catalyst of Fe–g–C3N4 shows excellent reusability and stability, and can be a promising candidate for decontamination of wastewater.

Insulin polymorphism induced by two polyphenols: new crystal forms and advances in macromolecular powder diffraction

2020 ◽  
Vol 76 (11) ◽  
pp. 1065-1079 ◽  
Author(s):  
Dimitris-Panagiotis Triandafillidis ◽  
Nikolaos Parthenios ◽  
Maria Spiliopoulou ◽  
Alexandros Valmas ◽  
Christos Kosinas ◽  
...  
Keyword(s):  
Data Collection ◽  
Powder Diffraction ◽  
Intermediate Phase ◽  
European Synchrotron Radiation Facility ◽  
X Ray Diffraction ◽  
Structural Behaviour ◽  
Crystal Forms ◽  
X Ray ◽  
Wide Ph Range ◽  
Ph Range

This study focuses on the polymorphism of human insulin (HI) upon the binding of the phenolic derivatives p-coumaric acid or trans-resveratrol over a wide pH range. The determination of the structural behaviour of HI via X-ray powder diffraction (XRPD) and single-crystal X-ray diffraction (SCXRD) is reported. Four distinct polymorphs were identified, two of which have not been reported previously. The intermediate phase transitions are discussed. One of the novel monoclinic polymorphs displays the highest molecular packing among insulin polymorphs of the same space group to date; its structure was elucidated by SCXRD. XRPD data collection was performed using a variety of instrumental setups and a systematic comparison of the acquired data is presented. A laboratory diffractometer was used for screening prior to high-resolution XRPD data collection on the ID22 beamline at the European Synchrotron Radiation Facility. Additional measurements for the most representative samples were performed on the X04SA beamline at the Swiss Light Source (SLS) using the MYTHEN II detector, which allowed the detection of minor previously untraceable impurities and dramatically improved the d-spacing resolution even for poorly diffracting samples.

scholarly journals Adsorption of Cationic Dyes on a Magnetic 3D Spongin Scaffold with Nano-Sized Fe3O4 Cores

Marine Drugs ◽  
2021 ◽  
Vol 19 (9) ◽  
pp. 512
Author(s):  
Maryam Akbari ◽  
Hessam Jafari ◽  
Mojtaba Rostami ◽  
Gholam Reza Mahdavinia ◽  
Ali Sobhani nasab ◽  
...  
Keyword(s):  
Organic Contaminants ◽  
Electrostatic Interactions ◽  
Organic Dyes ◽  
Three Dimensional ◽  
High Capacity ◽  
Cationic Dyes ◽  
X Ray Diffraction ◽  
Prepared Material ◽  
Wide Ph Range ◽  
Ph Range

The renewable, proteinaceous, marine biopolymer spongin is yet the focus of modern research. The preparation of a magnetic three-dimensional (3D) spongin scaffold with nano-sized Fe3O4 cores is reported here for the first time. The formation of this magnetic spongin–Fe3O4 composite was characterized by X-ray diffraction (XRD), thermogravimetric analysis (TGA), differential thermal analysis (DTA) (TGA-DTA), vibrating sample magnetometer (VSM), Fourier-transform infrared spectroscopy (FTIR), and zeta potential analyses. Field emission scanning electron microscopy (FE-SEM) confirmed the formation of well-dispersed spherical nanoparticles tightly bound to the spongin scaffold. The magnetic spongin–Fe3O4 composite showed significant removal efficiency for two cationic dyes (i.e., crystal violet (CV) and methylene blue (MB)). Adsorption experiments revealed that the prepared material is a fast, high-capacity (77 mg/g), yet selective adsorbent for MB. This behavior was attributed to the creation of strong electrostatic interactions between the spongin–Fe3O4 and MB or CV, which was reflected by adsorption mechanism evaluations. The adsorption of MB and CV was found to be a function of pH, with maximum removal performance being observed over a wide pH range (pH = 5.5–11). In this work, we combined Fe3O4 nanoparticles and spongin scaffold properties into one unique composite, named magnetic spongin scaffold, in our attempt to create a sustainable absorbent for organic wastewater treatment. The appropriative mechanism of adsorption of the cationic dyes on a magnetic 3D spongin scaffold is proposed. Removal of organic dyes and other contaminants is essential to ensure healthy water and prevent various diseases. On the other hand, in many cases, dyes are used as models to demonstrate the adsorption properties of nanostructures. Due to the good absorption properties of magnetic spongin, it can be proposed as a green and uncomplicated adsorbent for the removal of different organic contaminants and, furthermore, as a carrier in drug delivery applications.

scholarly journals Application of MIL-53(Fe) metal-organic framework material in catalytic wet oxidation of phenol

2021 ◽  
Vol 10 (1) ◽  
pp. 28-32
Author(s):  
Danh Huynh Thanh ◽  
Nghi Nguyen Huu ◽  
Du Pham Dinh
Keyword(s):  
Metal Organic Framework ◽  
Phenol Oxidation ◽  
Oxidation Reactions ◽  
Catalytic Wet Oxidation ◽  
X Ray Diffraction ◽  
Initial Ph ◽  
Wide Ph Range ◽  
Metal Organic ◽  
Ph Range ◽  
Organic Framework

In the present study, MIL-53(Fe) metal-organic framework material was applied as catalyst for phenol oxidation reaction in aqueous solution with H2O2 under UV radiation. The materials were characterized using X-ray diffraction (XRD), and fourier transform infrared spectroscopy (FT-IR). The effects of reaction time, initial phenol concentration, and initial pH of the solution on phenol oxidation reactions were investigated. The results indicated that MIL-53(Fe) could work effectively in the wide pH range from 2 to 10. Phenol was quickly oxidized to form simple organic acids, including acetic acid, formic acid and oxalic acid.

scholarly journals Reaction mechanisms of alkali-activated materials

2021 ◽  
Vol 14 (3) ◽  
Author(s):  
Markssuel Teixeira Marvila ◽  
Afonso Rangel Garcez de Azevedo ◽  
Carlos Maurício Fontes Vieira
Keyword(s):  
Reaction Products ◽  
X Ray Diffraction ◽  
Historical Monuments ◽  
Nuclear Magnetic Resonance Spectrometry ◽  
Magnetic Resonance Spectrometry ◽  
Definition Of ◽  
Kinetics Of ◽  
Furnace Slag ◽  
Alkali Activated

abstract: The Alkali-Activated Materials (AAM) are defined as materials obtained through the reaction between precursors and activators, and are separated into two classes depending on the products formed in the reaction, those rich in calcium, as the blast furnace slag, whose Ca/(Si+Al) ratio is higher than 1; and poor in calcium, which is the geopolymers subclass. In this review article, some bibliographical aspects were discussed regarding the discovery of these materials, through research conducted by Victor Glukhovsky and through the characterization of historical monuments by Davidovits, which began in the 50s and 60s and persist to the present day. The main products obtained in the alkaline activation reaction were also addressed, using the definition of polysialates and zeolites, in the case of geopolymers, and the tobermorite structure, in the case of materials rich in calcium. The main steps of the alkali-activated reaction, such as dissolution, condensation, polycondensation, crystallization, and hardening, were discussed. Some techniques for characterizing the AA reaction products were also examined, such as X-ray diffraction (XRD), nuclear magnetic resonance spectrometry (NMR), Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM). Finally, the main factors that interfere in the kinetics of AA reactions were explored, in which the type of cure and the activating solution used in the alkali-activated materials production stands out.

New Copper Compounds with Antiplatelet Aggregation Activity

2019 ◽  
Vol 15 (8) ◽  
pp. 850-862
Author(s):  
Mirthala Flores-García ◽  
Juan Manuel Fernández-G. ◽  
Cristina Busqueta-Griera ◽  
Elizabeth Gómez ◽  
Simón Hernández-Ortega ◽  
...  
Keyword(s):  
Schiff Base ◽  
Solid State ◽  
Thrombotic Event ◽  
X Ray Diffraction ◽  
Nmr Studies ◽  
Schiff Base Ligands ◽  
X Ray ◽  
Antiplatelet Aggregation ◽  
Aggregation Activity ◽  
L1 And L2

Background: Ischemic heart disease, cerebrovascular accident, and venous thromboembolism have the presence of a thrombotic event in common and represent the most common causes of death within the population. Objective: Since Schiff base copper(II) complexes are able to interact with polyphosphates (PolyP), a procoagulant and potentially prothrombotic platelet agent, we investigated the antiplatelet aggregating properties of two novel tridentate Schiff base ligands and their corresponding copper( II) complexes. Methods: The Schiff base ligands (L1) and (L2), as well as their corresponding copper(II) complexes (C1) and (C2), were synthesized and characterized by chemical analysis, X-ray diffraction, mass spectrometry, and UV-Visible, IR and far IR spectroscopy. In addition, EPR studies were carried out for (C1) and (C2), while (L1) and (L2) were further analyzed by 1H and 13C NMR. Tests for antiplatelet aggregation activities of all of the four compounds were conducted. Results: X-ray diffraction studies show that (L1) and (L2) exist in the enol-imine tautomeric form with a strong intramolecular hydrogen bond. NMR studies show that both ligands are found as enol-imine tautomers in CDCl3 solution. In the solid state, the geometry around the copper(II) ion in both (C1) and (C2) is square planar. EPR spectra suggest that the geometry of the complexes is similar to that observed in the solid state by X-ray crystallography. Compound (C2) exhibited the strongest antiplatelet aggregation activity. Conclusion: Schiff base copper(II) complexes, which are attracting increasing interest, could represent a new approach to treat thrombosis by blocking the activity of PolyP with a potential anticoagulant activity and, most importantly, demonstrating no adverse bleeding events.

Polarographic and spectrophotometric behaviour of some N-p-phenyl substituted benzamidines

1991 ◽  
Vol 56 (12) ◽  
pp. 2791-2799 ◽  
Author(s):  
Juan A. Squella ◽  
Luis J. Nuñez-Vergara ◽  
Hernan Rodríguez ◽  
Amelia Márquez ◽  
Jose M. Rodríguez-Mellado ◽  
...  
Keyword(s):  
Spectrophotometric Study ◽  
Absorption Bands ◽  
Electrochemical Parameters ◽  
Wide Ph Range ◽  
Group A ◽  
Substituent Constants ◽  
Ph Range ◽  
The Waves

Five N-p-phenyl substituted benzamidines were studied by DC and DP polarography in a wide pH range. Coulometric results show that the overall processes are four-electron reductions. Logarithmic analysis of the waves indicate that the process are irreversible. The influence of the pH on the polarographic parameters was also studied. A UV spectrophotometric study was performed in the pH range 2-13. In basic media some variations in the absorption bands were observed due to the dissociation of the amidine group. A determination of the pK values was made by deconvolution of the spectra. Correlations of both the electrochemical parameters and spectrophotometric pK values with the Hammett substituent constants were obtained.

Efficient Preconcentration of Cu2+, Zn2+ and Fe3+ with an Agarose-Schiff Base Sorbent

2007 ◽  
Vol 72 (7) ◽  
pp. 908-916 ◽  
Author(s):  
Payman Hashemi ◽  
Hatam Hassanvand ◽  
Hossain Naeimi
Keyword(s):  
Schiff Base ◽  
Metal Ions ◽  
Metal Ion ◽  
Good Accuracy ◽  
Kinetic Studies ◽  
Sample Volume ◽  
Effects Of Ph ◽  
Glass Column ◽  
High Concentrations ◽  
Ph Range

Sorption and preconcentration of Cu2+, Zn2+ and Fe3+ on a salen-type Schiff base, 2,2'- [ethane-1,2-diylbis(nitrilomethylidyne)]bis(2-methylphenol), chemically immobilized on a highly crosslinked agarose support, were studied. Kinetic studies showed higher sorption rates of Cu2+ and Fe3+ in comparison with Zn2+. Half-times (t1/2) of 31, 106 and 58 s were obtained for sorption of Cu2+, Zn2+ and Fe3+ by the sorbent, respectively. Effects of pH, eluent concentration and volume, ionic strength, buffer concentration, sample volume and interferences on the recovery of the metal ions were investigated. A 5-ml portion of 0.4 M HCl solution was sufficient for quantitative elution of the metal ions from 0.5 ml of the sorbent packed in a 6.5 mm i.d. glass column. Quantitative recoveries were obtained in a pH range 5.5-6.5 for all the analytes. The volumes to be concentrated exceeding 500 ml, ionic strengths as high as 0.5 mol l-1, and acetate buffer concentrations up to 0.3 mol l-1 for Zn2+ and 0.4 mol l-1 for Cu2+ and Fe3+ did not have any significant effect on the recoveries. The system tolerated relatively high concentrations of diverse ions. Preconcentration factors up to 100 and detection limits of 0.31, 0.16 and 1.73 μg l-1 were obtained for Cu2+, Zn2+ and Fe3+, respectively, for their determination by a flame AAS instrument. The method was successfully applied to the metal ion determinations in several river water samples with good accuracy.

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