Calculation of the UV-visible spectra and the stability of Mo and Re oxysulfides in aqueous solution

2005 ◽  
Vol 69 (10) ◽  
pp. 2497-2503 ◽  
Author(s):  
J.A. Tossell
Keyword(s):  
Aqueous Solution ◽  
Visible Spectra ◽  
Uv Visible ◽  
The Stability

scholarly journals Study of the β-Cyclodextrin Imipramine Hydrochloride Inclusion Complex and Determination of its Stability Constant (K) by UV-Visible Spectroscopy

2007 ◽  
Vol 4 (4) ◽  
pp. 550-558 ◽  
Author(s):  
Alamdar Ashnagar ◽  
Nahid Gharib Naseri ◽  
Bita Khanaki
Keyword(s):  
Stability Constant ◽  
Inclusion Complex ◽  
Visible Spectroscopy ◽  
Constant Amount ◽  
A Value ◽  
Visible Spectra ◽  
Imipramine Hydrochloride ◽  
Uv Visible ◽  
The Stability

In this research, the interactions of imipramine hydrochloride drug with β- cyclodextrin and the stability constant (K) of the inclusion complex formed between them were investigated by using UV-visible spectroscopy. Solutions consisting of a known and constant amount of imipramine hydrochloride and varying amounts of β- cyclodextrin were prepared in 0.1 M phosphate buffer (pH 7.4). The final solutions had cyclodextrin concentrations between 0.0011 and 0.0153 M. UV-visible spectra of each solution was taken at λmax= 250 nm. The absorbances at this wavelength were recorded and plotted against cyclodextrin concentrations. From the graph, the concentrations of free and bound imipramine hydrochloride and free β-cyclodextrin were calculated using the Beer-Lambert law. From these data, the stability constant was calculated and a value of K=52.26±11.41 mol-1L was obtained. The magnitude of the stability constant is discussed in terms of the relative sizes and the chemical natures of β-cyclodextrin and imipramine hydrochloride.

Stability of Vanadium Electrolytes in the Vanadium Redox Flow Battery

2013 ◽  
Vol 1492 ◽  
pp. 25-31
Author(s):  
Shu-Yuan Chuang ◽  
Chih-Hsing Leu ◽  
Kan-Lin Hsueh ◽  
Chun-Hsing Wu ◽  
Hsiao-Hsuan Hsu ◽  
...  
Keyword(s):  
Oxidation Process ◽  
Negative Electrode ◽  
Vanadium Redox Flow Battery ◽  
Redox Flow Battery ◽  
Flow Battery ◽  
Oxidation Rates ◽  
Visible Spectra ◽  
Uv Visible ◽  
The Stability ◽  
Vanadium Redox

ABSTRACTThe stability of the negative electrode electrolyte affects the efficiency and capacity of energy storage in the vanadium redox flow battery (VRFB) system. To explore the stability of vanadium electrolytes, the study prepared five types of V(II) electrolytes that were exposed to air in a fixed open area and monitored the charge state of vanadium ions over time by UV/Visible spectrophotometer. This study succeeded in preparing pure V(II) electrolytes. Five characteristics are found in the UV/Visible spectra, respectively, during the oxidation process from V(II) electrolytes to V(III) electrolytes and V(III) electrolytes to V(IV) electrolytes. The experimental results show that the oxidation rate of a solution of 1 M V(II) electrolytes to V(III) electrolytes and 1 M V(III) electrolytes to V(IV) electrolytes under an atmosphere of air is 4.79 and 0.0089 mol/h per square meter. The oxidation rates of 0.05-1 M V(II) electrolytes to V(III) electrolytes are approximately 96-538 times than that of V(III) electrolytes to V(IV) electrolytes.

Synthesis and optical properties of composites based on ternary Zn1–xCdxS nanoparticles enclosed in a layered octosilicate

Clay Minerals ◽  
2014 ◽  
Vol 49 (5) ◽  
pp. 703-716 ◽  
Author(s):  
Y. Chen ◽  
Z. Yu ◽  
G. Yu ◽  
Y. Yan
Keyword(s):  
Optical Properties ◽  
Interlayer Space ◽  
Layered Silicate ◽  
Transmission Band ◽  
Molar Ratio ◽  
Basal Spacing ◽  
Visible Spectra ◽  
Uv Visible ◽  
The Stability ◽  
Properties Of Composites

AbstractIn order to improve the optical properties and enhance the stability of Zn1–xCdxS nanoparticles, which are important optoelectrical materials, the ternary Zn1–xCdxS nanoparticles were enclosed in a layered octosilicate by a three-step process, namely (i) protonation of Naoctosilicate, (ii) ion-exchange in order to introduce Zn and Cd ions into the interlayer space, and (iii) addition of S2– to form Zn1–xCdxS particles in the interlayer space of the octosilicate. The basal spacing (~10 Å) of the final ZnCdS-Oct-n (n = 1, 2, 3, 4) composites noticeably increased in comparison with that of the precursor H-Oct (7.5 Å). This may be attributed to the incorporation of larger size Zn1–xCdxS particles into the interlayer space of H-Oct. The UV-visible spectra of the composites suggested that the transmission band-edges gradually shifted to low energy with increasing molar ratio of Cd/Zn. Moreover, the transmission band-edges of the composites are between those of layered Octosilicate, ZnS, and CdS. TEM observation confirmed that the size of Zn1–xCdxS nanoparticles enclosed in the layered silicate was about ~3–5 nm.

scholarly journals Supramolecular Encapsulation of Vitamin B6by Macrocyclic Nanocontainer Cucurbit[7]uril

2015 ◽  
Vol 2015 ◽  
pp. 1-6 ◽  
Author(s):  
Wanying Li ◽  
Shengke Li ◽  
Ian W. Wyman ◽  
Donal H. Macartney ◽  
Qingwen Zhang ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Molecular Modeling ◽  
Vitamin B ◽  
Pyridoxine Hydrochloride ◽  
Biologically Relevant ◽  
H Nmr ◽  
Molecular Container ◽  
Uv Visible ◽  
The Stability ◽  
First Time

A pharmaceutically and biologically relevant molecule, pyridoxine hydrochloride (vitamin B6), was encapsulated inside the cavity of a molecular container, cucurbit[7]uril (CB[7]), in aqueous solution. The CB[7] based “nanocapsule” of vitamin B6has been investigated for the first time, via1H NMR and UV-visible spectroscopic titrations (including Job’s plot) andab initiomolecular modeling. The results have demonstrated that vitamin B6forms stable host-guest complexes within CB[7] in 1 : 1 stoichiometry, with a binding affinity of(4.0±0.5)×103 M−1. Such a nanocapsule could potentially find application in vitamin B6formulation for the purpose of enhancing the stability, absorption, and delivery of this important vitamin.

TUNING OF BLOCK COPOLYMER-MEDIATED SYNTHESIS OF GOLD NANOPARTICLES

2011 ◽  
Vol 10 (04n05) ◽  
pp. 1035-1038 ◽  
Author(s):  
DEBES RAY ◽  
V. K. ASWAL ◽  
D. SRIVASTAVA
Keyword(s):  
Gold Nanoparticles ◽  
Block Copolymer ◽  
Number Density ◽  
Copolymer Concentration ◽  
Transmission Electron ◽  
Visible Spectra ◽  
Block Copolymer Micelles ◽  
Uv Visible ◽  
Copolymer Micelles ◽  
The Stability

The yield and stability of synthesis of gold nanoparticles has been examined using triblock copolymer Pluronic P85 (EO26PO39EO26) at varying concentrations as a function of hydrogen tetrachloroaureate (III) hydrate (HAuCl4.3H2O) in aqueous solution. The surface plasmon resonance in the time-dependent UV-Visible spectra reveals that increase in the block copolymer concentration increases the yield of the gold nanoparticles but decreases their stability. Small-angle neutron scattering (SANS) suggests that the number density of block copolymer micelles increase almost linearly with the concentration, which is related to result in higher numbers of nucleation centers and therefore increase in the yield of gold nanoparticles. The fact that increase in the number density of nanoparticles also increases the chances of aggregation and this tends to decrease the stability at higher block copolymer concentration. Transmission electron microscopy (TEM) images confirm the larger sizes of the nanoparticles formed in these systems at higher concentrations.

Infrared and UV-visible spectra of layer semiconductors Gas, GaSe and GaTe

1977 ◽  
Vol 38 (10) ◽  
pp. 1293-1299 ◽  
Author(s):  
U. Giorgianni ◽  
G. Mondio ◽  
P. Perillo ◽  
G. Saitta ◽  
G. Vermiglio
Keyword(s):  
Visible Spectra ◽  
Uv Visible

REMOVAL OF HEAVY METAL Cr (II), Ni (II), Cu (II), Zn (II), Cd (II), Pb (II) IONS FROM AQUEOUS SOLUTION BY MENTHA PIPERITA EXTRACT

2020 ◽  
pp. 15-20
Author(s):  
Ersin Yucel ◽  
Mine Yucel
Keyword(s):  
Aqueous Solution ◽  
Metal Ions ◽  
High Efficiency ◽  
Correlation Coefficients ◽  
Langmuir Model ◽  
Mentha Piperita ◽  
Freundlich Model ◽  
Biosorption Capacity ◽  
Peppermint Extract ◽  
The Stability

In this study, the usage of the peppermint (Mentha piperita) for extracting the metal ions [Mg (II), Cr (II), Ni (II), Cu (II), Zn (II), Cd (II), Pb (II)] that exist at water was investigated. In order to analyze the stability properties, Langmuir, Freundlich, Temkin and Dubinin-Radushkevich isotherms were used at removing the metal ions and the highest correlation coefficients (R2) were obtained at Langmuir isotherm. Therefore, it is seen that the Langmuir model is more proper than the Freundlich model. However, it was found that the correlation coefficients of removing Ni and Cd is higher at Freundlich model than Langmuir and low at Dubinin-Radushkevich isotherm. It is established that the biosorption amount increase depends on the increase of biosorbent and it can be achieved high efficiency (95%) even with small amount (0.6 mg, peppermint extract) at lead ions. It is also determined that the peppermint extracted that is used at this study shows high biosorption capacity for metal ions and can be used for immobilization of metals from polluted areas.

Structure of the complexes of ethylenediphosphinetetraacetic acid in solution

1985 ◽  
Vol 50 (2) ◽  
pp. 445-453 ◽  
Author(s):  
Jana Podlahová ◽  
Josef Šilha ◽  
Jaroslav Podlaha
Keyword(s):  
Metal Ion ◽  
Carboxyl Groups ◽  
Complex Solution ◽  
Square Planar ◽  
Weak Complexes ◽  
Carboxylic Groups ◽  
Uv Visible ◽  
The Stability ◽  
Tetrahedral Complexes ◽  
Free Carboxyl

Ethylenediphosphinetetraacetic acid is bonded to metal ions in aqueous solutions in four ways, depending on the type of metal ion: 1) through an ionic bond of the carboxylic groups to form weak complexes with a metal:ligand ratio of 1 : 1 (Ca(II), Mn(II), Zn(II), Pb(II), La(III)); 2) through type 1) bond with contributions from weak interaction with the phosphorus (Cd(II)); 3) through coordination of the ligand as a monodentate P-donor with the free carboxyl groups with formation of 2 : 1 and 1 : 1 complexes (Cu(I), Ag(I)); 4) through formation of square planar or, for Hg(II), tetrahedral complexes with a ratio of 1 : 2 with the ligand as a bidentate PP-donor with the free carboxyl groups (Fe(II), Co(II), Ni(II), Pd(II), Pt(II)). On acidification of the complex solution, the first two protons are bonded to the carboxyl groups. The behaviour during further protonation depends on the type of complex: in complexes of types 1) and 2) phosphorus is protonated and the complex dissociates; in complexes of types 3) and 4) the free carboxyl groups are protonated and the phosphorus-metal bond remains intact. The results are based on correlation of the stability constants, UV-visible, infrared, 1H and 31P NMR spectra and magnetic susceptibilities of the complexes in aqueous solution.

scholarly journals A Novel Thiosemicarbazide-Based Fluorescent Chemosensor for Hypochlorite in Near-Perfect Aqueous Solution and Zebrafish

Chemosensors ◽  
2021 ◽  
Vol 9 (4) ◽  
pp. 65
Author(s):  
Minji Lee ◽  
Donghwan Choe ◽  
Soyoung Park ◽  
Hyeongjin Kim ◽  
Soomin Jeong ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Reactive Oxygen Species ◽  
Aqueous Solution ◽  
Fluorescence Quenching ◽  
Limit Of Detection ◽  
Fluorescent Sensor ◽  
Ionization Mass ◽  
Oxygen Species ◽  
Marked Selectivity ◽  
Uv Visible

A novel thiosemicarbazide-based fluorescent sensor (AFC) was developed. It was successfully applied to detect hypochlorite (ClO−) with fluorescence quenching in bis-tris buffer. The limit of detection of AFC for ClO− was analyzed to be 58.7 μM. Importantly, AFC could be employed as an efficient and practical fluorescent sensor for ClO− in water sample and zebrafish. Moreover, AFC showed a marked selectivity to ClO− over varied competitive analytes with reactive oxygen species. The detection process of AFC to ClO− was illustrated by UV–visible and fluorescent spectroscopy and electrospray ionization–mass spectrometry (ESI–MS).

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