scholarly journals Diverse isostructural MOFs by postsynthetic metal node metathesis: anionic-to-cationic framework conversion, luminescence and separation of dyes

2015 ◽  
Vol 3 (45) ◽  
pp. 22915-22922 ◽  
Author(s):  
Soana Seth ◽  
Govardhan Savitha ◽  
Jarugu Narasimha Moorthy
Keyword(s):  
Metal Ions ◽  
Chemical Nature ◽  
Organic Dye ◽  
Ionic Radii ◽  
Cationic Framework

Postsynthetic metal-node metathesis of a flexible, yet robust porous anionic Cd–MOF with different metal ions of varying ionic radii, charges and chemical nature leads to diverse isostructural MOFs. The Eu@MOF and Tb@MOF – accessed by PSME – are brilliantly luminescent. The modified MOFs permit organic dye separation.

The facile soft-template-morphology-controlled (STMC) synthesis of ZnIn2S4 nanostructures and their excellent morphology-dependent adsorption properties

2020 ◽  
Vol 8 (4) ◽  
pp. 1986-2000 ◽  
Author(s):  
Afaq Ahmad Khan ◽  
Arif Chowdhury ◽  
Sunita Kumari ◽  
Sahid Hussain
Keyword(s):  
Metal Ions ◽  
Toxic Metal ◽  
Adsorption Properties ◽  
Organic Dye ◽  
Soft Template ◽  
Toxic Metal Ions ◽  
Controlled Morphology

ZnIn2S4 nanostructures were fabricated with controlled morphology and utilized for the adsorption of an organic dye and toxic metal ions.

scholarly journals The effect of metal ions on the activity and thermostability of the extracellular proteinase from a thermophilic Bacillus, strain EA.1

1992 ◽  
Vol 287 (2) ◽  
pp. 367-374 ◽  
Author(s):  
T Coolbear ◽  
J M Whittaker ◽  
R M Daniel
Keyword(s):  
Metal Ions ◽  
Calcium Ions ◽  
Inhibitory Effect ◽  
Decay Kinetics ◽  
Ionic Radii ◽  
Thermophilic Bacillus ◽  
Bacillus Strain ◽  
Bivalent Cations ◽  
Maximum Stability

The proteinase from the extremely thermophilic Bacillus strain EA.1 exhibits maximum stability at a pH of approx. 6.5. In the presence of calcium ions the half-life at 95 degrees C of the enzyme at this pH was 17 min, and loss of activity followed first-order decay kinetics. The role of metal ions in the activity and stability of the enzyme was studied using the holoenzyme, the metal-depleted apoenzyme, and a zinc-enriched apoenzyme preparation. Zinc and calcium ions were the preferred bivalent cations for the active site and stabilization site(s) respectively. Stabilization by metal ions was not in itself a highly stringent process, but ions other than calcium which stabilized the enzyme generally had a concomitant inhibitory effect on activity. Inhibition and stabilization of the enzyme by cations were concentration-dependent effects and certain ions activated the apoenzyme but not the holoenzyme. Manganese(II) ions conferred some stability and also activated the enzyme, but in the latter case were not as effective as zinc ions. The results are discussed with reference to the ionic radii, co-ordination number and preferred ligand donors of the ions. Mercury(II) ions severely compromised enzyme activity and stability, and the effects of thiol-reactive agents suggest that thiol groups also have a role in enzyme integrity.

Molecular mobility in protein solutions containing metal ions with various ionic radii

2009 ◽  
Vol 64 (4) ◽  
pp. 446-449 ◽  
Author(s):  
I. A. Sergeeva ◽  
N. V. Sokol ◽  
M. S. Ivanova ◽  
G. P. Petrova ◽  
Yu. M. Petrusevich
Keyword(s):  
Metal Ions ◽  
Molecular Mobility ◽  
Protein Solutions ◽  
Ionic Radii

Recent progress in the development of organic dye based near-infrared fluorescence probes for metal ions

2018 ◽  
Vol 354 ◽  
pp. 74-97 ◽  
Author(s):  
Di Wu ◽  
Liyan Chen ◽  
Woolin Lee ◽  
Gyeongju Ko ◽  
Jun Yin ◽  
...  
Keyword(s):  
Metal Ions ◽  
Recent Progress ◽  
Near Infrared ◽  
Organic Dye ◽  
Fluorescence Probes ◽  
Near Infrared Fluorescence

scholarly journals On the Unsuspected Role of Multivalent Metal Ions on the Charge Storage of a Metal Oxide Electrode in Mild Aqueous Electrolytes

2019 ◽  
Author(s):  
Yee-Seul Kim ◽  
Kenneth D. Harris ◽  
Benoit Limoges ◽  
Véronique Balland
Keyword(s):  
Metal Oxide ◽  
Metal Ions ◽  
Chemical Nature ◽  
Aqueous Electrolyte ◽  
Charge Storage ◽  
Aqueous Electrolytes ◽  
Oxide Electrode ◽  
Multivalent Metal

<p>The main objective of the work is to elucidate and rationalize the role played by an Al<sup>3+</sup>-based aqueous electrolyte on the charge accumulated in model mesoporous TiO<sub>2</sub> electrodes and to decipher the chemical nature of the inserting cation.<br></p>

scholarly journals An Examination of the Electron Densities in a Series of Tripodal Cobalt Complexes Bridged by Magnesium, Calcium, Strontium and Barium

2018 ◽  
Author(s):  
John Bacsa ◽  
Fernando Cortés-Guzmán ◽  
Lillian G. G. Ramírez-Palma ◽  
Christian Wallen ◽  
Christopher Scarborough
Keyword(s):  
Metal Ions ◽  
Electronic Structures ◽  
Alkaline Earth ◽  
Earth Metal ◽  
Alkaline Earth Metal ◽  
Ionic Radii ◽  
X Ray ◽  
Alkaline Earth Metal Ions ◽  
Local Properties ◽  
Insight Into

X-ray crystallographic and theoretical charge density data for a series of compounds [(Co(Ts3tren))M(Co(Ts3tren))] (M = Mg, Ca, Sr and Ba) is examined. The crystal structures are isostructural and the alkaline earth metal ions have the same arrangement of donor oxygen atoms despite the large variation in ionic radii. The isomorphism of these molecules is surprising and a theoretical examination of the electronic structures, with the different metal ions along the series, provides detailed insight into their stabilities. The theoretical and experimental data are consistent and agree well. The local properties of the Co(II) ion and its donor atoms are relatively independent of the alkali earth metal.

Effects of Rare Earth Dopants on Crystal Structures of Bismuth Molybdate Catalysts

2011 ◽  
Vol 295-297 ◽  
pp. 1046-1049
Author(s):  
Ying Zhi Cheng ◽  
Li Xue ◽  
Xiu Yu Sun ◽  
Zhong Bo Hu
Keyword(s):  
Catalytic Activity ◽  
Rare Earth ◽  
Metal Ions ◽  
Crystal Structures ◽  
Powder Diffraction Data ◽  
Bismuth Molybdate ◽  
Ionic Radii ◽  
X Ray ◽  
Bond Lengths ◽  
Average Bond

Crystal structures of Bi2Mo3O12 and Bi1.8Ln0.2Mo3O12 (Ln = Ce, Nd, Dy, Er) were studied using Rietveld structural refinements of X-ray powder diffraction data. Substitution of 10 mol% Ln for Bi produced changes in lattice parameters, bond lengths and distances between metal ions. These changes such as decreases in average bond lengths of Mo1O4 tetrahedra and variations in the distances between adjacent metal ions on the same plane could be ascribed to different ionic radii and electronegativty of Bi and rare earth atoms, and might be related to catalytic activity of bismuth molybdate for the selective oxidation and ammoxidation of alkenes.

Garnets as indices of progressive regional metamorphism

1967 ◽  
Vol 36 (277) ◽  
pp. 89-93 ◽  
Author(s):  
Kamal Nandi
Keyword(s):  
Metal Ions ◽  
Thermal Stresses ◽  
Recent Literature ◽  
Regional Metamorphism ◽  
Metamorphic Grade ◽  
Chemical Analyses ◽  
Ionic Radii ◽  
Good Index ◽  
Hyperbolic Curve

SummaryGarnets undergo readjustment of ion-assemblages under external mechanical and thermal stresses; this adjustment favours those paths that annul the very cause to which it is due. Metal ions in garnets being replaceable, with rising metamorphism garnets become reluctant to accommodate ions of larger ionic radii.Data from recent literature on chemical analyses of garnets from rocks belonging to different grades of regional metamorphism reveal that the (FeO + MgO) content of garnet varies linearly with (CaO + MnO) content. As the Fe/Mg ratio does not vary appreciably, a fair estimate of metamorphic grade can be made from a knowledge of (CaO + MnO) or of (FeO +MgO) individually or even, with less confidence, of FeO or MgO alone. From the study of the available data it is found that (CaO + MnO) and (FeO + MgO)/(CaO + MnO) provide the best indicators of progressive metamorphism. Cell edges of garnets decrease progressively with increasing metamorphism and this may also be used as a fairly good index of metamorphism. When cell edges are plotted against (FeO + MgO)/(CaO + MnO), a hyperbolic curve is obtained.

Alginate Polyelectrolyte Ionotropic Gels-XVI. Kinetics and Chemical Equilibria Studies for Heterogeneous Ion Exchange of Polyvalent Metal Ions in Alginate Gel Complexes

1992 ◽  
Vol 4 (3) ◽  
pp. 173-179 ◽  
Author(s):  
S. A. El-Shatoury ◽  
R. M. Hassan ◽  
A. A. Said
Keyword(s):  
Ionic Strength ◽  
Ion Exchange ◽  
Metal Ions ◽  
Thermodynamic Parameters ◽  
Coordination Geometry ◽  
Ionic Radii ◽  
Chemical Equilibria ◽  
Polyvalent Metal ◽  
Alginate Gel ◽  
Counter Ions

The kinetics or chemical equilibria of exchange of Ca(II), Sr(II), Ba(I), Zn(II), Cd(II), Al(III), Fe(III), Se(IV), Ce(IV) and Th(IV) counter ions in alginate gel complexes by H+ ions have been investigated titrimetrically and conductimetrically at a constant ionic strength of 0.1 mol/dm3. The thermodynamic parameters have been evaluated and are discussed in terms of ionic radii and polarizability of the metal ions, coordination geometry, and stability of the gel complexes.

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