scholarly journals A Highly Selective Turn-On Fluorescent Probe for the Detection of Zinc

Molecules ◽  
2021 ◽  
Vol 26 (13) ◽  
pp. 3825
Author(s):  
Ling-Yi Shen ◽  
Xiao-Li Chen ◽  
Xian-Jiong Yang ◽  
Hong Xu ◽  
Ya-Li Huang ◽  
...  
Keyword(s):  
High Selectivity ◽  
Fluorescence Probe ◽  
Stoichiometric Ratio ◽  
X Ray Diffraction ◽  
X Ray ◽  
Turn On ◽  
Imine Nitrogen ◽  
System A ◽  
Plot Analysis ◽  
L System

A novel turn-on fluorescence probe L has been designed that exhibits high selectivity and sensitivity with a detection limit of 9.53 × 10−8 mol/L for the quantification of Zn2+. 1H-NMR spectroscopy and single crystal X-ray diffraction analysis revealed the unsymmetrical nature of the structure of the Schiff base probe L. An emission titration experiment in the presence of different molar fractions of Zn2+ was used to perform a Job’s plot analysis. The results showed that the stoichiometric ratio of the complex formed by L and Zn2+ was 1:1. Moreover, the molecular structure of the mononuclear Cu complex reveals one ligand L coordinates with one Cu atom in the asymmetric unit. On adding CuCl2 to the ZnCl2/L system, a Cu-Zn complex was formed and a strong quenching behavior was observed, which inferred that the Cu2+ displaced Zn2+ to coordinate with the imine nitrogen atoms and hydroxyl oxygen atoms of probe L.

Investigation of the products of carbothermal reduction of yttrium oxide by the hydrolysis method

1984 ◽  
Vol 49 (4) ◽  
pp. 936-943 ◽  
Author(s):  
Bohumil Hájek ◽  
Pavel Karen ◽  
Vlastimil Brožek
Keyword(s):  
Yttrium Oxide ◽  
Carbothermal Reduction ◽  
Stoichiometric Ratio ◽  
X Ray Diffraction ◽  
X Ray ◽  
Hydrolysis Method ◽  
Sample Decomposition ◽  
Products Of Reaction ◽  
Hydrolysis Of ◽  
Lower Carbon

For the investigation of the products of reaction of yttrium oxide with carbon mixed in various proportions, the chemical and X-ray diffraction methods of analysis were combined with the gas chromatographic analysis of the mixture of hydrocarbons and hydrogen formed on the sample decomposition with water. The carboreduction of Y2O3 was examined at relatively low temperatures, convenient for obtaining the reaction intermediates in higher yields. At 1 600 °C and pressures of 10-3 Pa the reduction of a mixture of Y2O3 with carbon in a stoichiometric ratio of 1 : 7 yields YC2 in equilibrium with 20% of Y2OC phase. At lower carbon contents (down to the Y2O3 : C ratio of 1 : 2) tha fraction of the Y2OC phase increases up to approximately 30%. In addition to Y2O3, the reaction mixture contains also Y2C, Y2OC and a phase giving propyne on hydrolysis. The presence of traces of C3 hydrocarbons and small amounts of methane in the product of hydrolysis of the carbide sample prepared by the carbothermal reduction of the oxide can be explained in terms of the occurrence of the Y15C19 phase, probably substituted in part by oxygen, and of the Y2OC phase. The results are compared with those obtained previously for the Sc2O3 + C system.

scholarly journals A Covalent Organic Cage Compound Acting as a Supramolecular Shadow Mask for the Regioselective Functionalization of C60

2020 ◽  
Author(s):  
Viktoria Leonhardt ◽  
Stefanie Fimmel ◽  
Ana-Maria Krause ◽  
Florian Beuerle
Keyword(s):  
Mass Spectrometry ◽  
Single Crystal ◽  
High Selectivity ◽  
Shadow Mask ◽  
X Ray Diffraction ◽  
X Ray ◽  
Trigonal Bipyramidal ◽  
Cage Compound ◽  
Vis Spectroscopy ◽  
Regioselective Functionalization

<div><div><div><p>A trigonal-bipyramidal covalent organic cage compound serves as an efficient host to form stable 1:1-complexes with C60 and C70. Fullerene encapsulation has been comprehensively studied by NMR and UV/Vis spectroscopy, mass spectrometry as well as single-crystal X-ray diffraction. Exohedral functionalization of encapsulated C60 via threefold Prato reaction revealed high selectivity for the symmetry-matched all-trans-3 addition pattern.</p></div></div></div>

scholarly journals Non-invasive Electrochemical Detection of Glucose using CuO-NiO/MXene Modified Electrode

2020 ◽  
Author(s):  
Alaa Mohamed Elsafi ◽  
Vinotha Krishnasamy ◽  
Karthik Kannan ◽  
John-John Cabibihan ◽  
Abdulaziz Khalid AlAli ◽  
...  
Keyword(s):  
Morphological Analysis ◽  
High Selectivity ◽  
Proton Conductor ◽  
Carbon Electrodes ◽  
Electrochemical Studies ◽  
X Ray Diffraction ◽  
Characterization Methods ◽  
Glassy Carbon Electrodes ◽  
X Ray ◽  
Non Invasive

High levels of glucose or acetone in breath confirms diabetes disease. One of the analytical devices that detect changes in breath is the electrochemical sensor having high selectivity, easy to use and being able to meet diabetic patient’s needs. In this study, sensors were made by fabricating metal oxide coated glassy carbon electrodes and using nafion as a proton conductor. Characterization methods such as X-ray diffraction, FTIR and morphological analysis have been performed for metal oxides to characterize their atomic arrangement and composition. In addition, electrochemical studies were done using Gamry instrument and curves plotted as current in amperes versus voltage to test the coated electrodes conductivity. High selectivity sensors provide promising applications in any field.

Catalytic Performance of Copper-Substituted Polyoxotungstate Materials and X-Ray Structure of a New Sandwich-Type Compound

2008 ◽  
Vol 587-588 ◽  
pp. 538-542 ◽  
Author(s):  
Salete S. Balula ◽  
Luís Cunha-Silva ◽  
Isabel C.M.S. Santos ◽  
Filipe A. Almeida Paz ◽  
João Rocha ◽  
...  
Keyword(s):  
Potassium Salt ◽  
Room Temperature ◽  
High Selectivity ◽  
Catalytic Performance ◽  
New Materials ◽  
X Ray Diffraction ◽  
Good Efficiency ◽  
X Ray ◽  
Sandwich Type ◽  
Copper Centre

Mono-substituted and sandwich-type copper substituted polyoxoanions ([PW11CuO39]5− and [Cu4(H2O)2(PW9O34)2]10−) were studied as catalysts for the epoxidation of cyclooctene and geraniol, using the green oxidant H2O2, with the results suggesting good efficiency at room temperature. High selectivity and reasonable conversion data were found after the first minutes of reaction. The copper centre may be responsible for this performance and our on-going research focuses in the preparation of new materials incorporating copper into polyoxometalates (POMs). In this context, we have also isolated a new crystalline dimeric sandwich-type polyoxocoppertungstate {H7.05[Cu3WO(H2O)(CuW9O34)(Cu0.6W9O34)]}7.75−. This compound was isolated as potassium salt and structurally characterized by FTIR and single-crystal X-ray diffraction (XRD). The polyoxoanion is composed by the [CuW9O34]12− and [Cu0.6W9O34]12.8− anionic fragments, joined together by a rhomb-like arrangement of three Cu2+ and one W6+ metallic centres, all exhibiting octahedral coordination geometries.

X-ray Diffraction Measurements via a UNIX+ Based System

1984 ◽  
Vol 28 ◽  
pp. 241-247
Author(s):  
D. S. Dunn ◽  
T. F. Marinis
Keyword(s):  
Operating System ◽  
Data Acquisition ◽  
X Ray Diffraction ◽  
X Ray ◽  
Software Interface ◽  
System A ◽  
Unix Operating System ◽  
Processing And Storage ◽  
Data Acquisition Program ◽  
And Storage

We have automated a Seeman-Bohlin Guinier x-ray diffractometer by interfacing it to a minimally configured PDP 11/23 computer. The programs that run on the microcomputer to control the operation of the diffractometer are stored on a mainframe host running the UNIX+ operating system. A software interface allows a particular data acquisition program to be downloaded from the UNIX host and executed on the satellite processor. This same interface allows the collected data to be periodically off-loaded to the host for processing and storage.

A High-Speed Signal Processor Using a Digital Divider for Position Sensitive Proportional Counters

1980 ◽  
Vol 24 ◽  
pp. 173-176
Author(s):  
S. Kobashi ◽  
K. Mochiki ◽  
K. Hasegawa ◽  
A. Sekiguchi ◽  
H. Hashizume ◽  
...  
Keyword(s):  
High Speed ◽  
Dead Time ◽  
Present System ◽  
X Ray Diffraction ◽  
Analog To Digital ◽  
X Ray ◽  
System A ◽  
Proportional Counters ◽  
Position Sensitive ◽  
A Charge

Most position sensitive proportional counters (PSPCs) currently used in X-ray diffraction experiments have a dead time longer than 5 μs. Though such PSPCs are useful in measuring weak diffraction diagrams, a faster counter is needed to detect strong X-ray diagrams produced with synchrotron radiation sources. The long dead time of PSPCs using a charge division position read-out is due to the slow analog division circuit plus analog-to-digital converter employed in the present system. A fast processor can be built utilising two high-speed ADCs to digitize voltage signals from the detector, followed by a digital divider to compute position of detected photons. The present paper describes the design of such a processor and some preliminary testings of its performances.

scholarly journals Crystallization and preliminary X-ray diffraction analysis of a single variable domain of the immunoglobulin superfamily in amphioxus,Amphi-IgSF-V

2014 ◽  
Vol 70 (8) ◽  
pp. 1072-1075 ◽  
Author(s):  
Bo Jiang ◽  
Yanjie Liu ◽  
Rong Chen ◽  
Zhenbao Wang ◽  
Mansoor Tariq ◽  
...  
Keyword(s):  
Immune System ◽  
Structural Information ◽  
Three Dimensional ◽  
Dimensional Structure ◽  
Immunoglobulin Superfamily ◽  
X Ray Diffraction ◽  
X Ray ◽  
Cell Parameters ◽  
System A ◽  
Human Immunoglobulins

Amphioxus is regarded as an essential animal model for the study of immune evolution. Discovery of new molecules with the immunoglobulin superfamily (IgSF) variable (V) domain in amphioxus would help in studying the evolution of IgSF V molecules in the immune system. A protein was found which just contains only one IgSF V domain in amphioxus, termedAmphi-IgSF-V; it has over 30% sequence identity to the V domains of human immunoglobulins and mammalian T-cell receptors. In order to clarify the three-dimensional structure of this new molecule in amphioxus,Amphi-IgSF-V was expressed, purified and crystallized, and diffraction data were collected to a resolution of 1.95 Å. The crystal belonged to space groupP3221, with unit-cell parametersa=b= 53.9,c= 135.5 Å. The Matthews coefficient and solvent content were calculated to be 2.58 Å3 Da−1and 52.38%, respectively. The results will provide structural information to study the evolution of IgSF V molecules in the immune system.

Synthesis, Characterization, and Ethylene Oligomerization and Polymerization by 2-Quinoxalinyl-6-iminopyridine Chromium Chlorides

2008 ◽  
Vol 61 (5) ◽  
pp. 397 ◽  
Author(s):  
Saliu A. Amolegbe ◽  
Maliha Asma ◽  
Min Zhang ◽  
Gang Li ◽  
Wen-Hua Sun
Keyword(s):  
High Selectivity ◽  
Ethylene Oligomerization ◽  
Distorted Octahedral Geometry ◽  
Electronic Effects ◽  
X Ray Diffraction ◽  
Reaction Conditions ◽  
Co Catalyst ◽  
X Ray ◽  
Catalytic Activities ◽  
Distorted Octahedral

A series of chromium(iii) complexes ligated by N^N^N tridentate 2-quinoxalinyl-6-iminopyridine were synthesized and characterized by elemental analysis and infrared spectroscopy. Single-crystal X-ray diffraction analysis for the structure of complex C3 reveals a distorted octahedral geometry. When methylaluminoxane was employed as the co-catalyst, the chromium complexes showed high activities for ethylene oligomerization and polymerization. The distribution of oligomers obtained followed Schulz–Flory rules with high selectivity for α-olefins. Both steric and electronic effects of coordinated ligands affected the catalytic activities as well as the properties of the catalytic products. The parameters of the reaction conditions were also investigated to explore the optimum catalytic potentials of these complexes.

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