Complex formation of beryllium sulfate in mixtures of water and dimethylformamide

1983 ◽  
Vol 36 (10) ◽  
pp. 1941 ◽  
Author(s):  
BI Gislason ◽  
H Strehlow
Keyword(s):  
Complex Formation ◽  
Sulfate Ion ◽  
Kinetic Measurements ◽  
Inner Sphere ◽  
Sphere Complex ◽  
Beryllium Sulfate ◽  
Rate Of Substitution

The complex formation of BeSO4 in mixtures of water and dimethylformamide (dmf) has been studied by using conductivity and kinetic measurements. In these solutions the complex Be(SO4)22- is shown to exist together with the outer- and inner-sphere complex of BeSO4. The rate of substitution depends on the composition of the solvatomer Be(H20)I(dmf)4-I2+ which reacts with the sulfate ion and on the kind of solvating molecule which is substituted by the ligand SO42-.

scholarly journals Silica Pillared Montmorillonites as Possible Adsorbents of Antibiotics from Water Media

2018 ◽  
Vol 8 (8) ◽  
pp. 1403 ◽  
Author(s):  
Maria Roca Jalil ◽  
Florencia Toschi ◽  
Miria Baschini ◽  
Karim Sapag
Keyword(s):  
Complex Formation ◽  
Aqueous Media ◽  
Pillared Clays ◽  
Raw Material ◽  
Van Der Waals Interactions ◽  
Adsorption Mechanisms ◽  
Adsorption Sites ◽  
Adsorption Capacities ◽  
Inner Sphere ◽  
Sphere Complex

In this work, three silica pillared clays (Si-PILC) were synthetized, characterized, and evaluated as possible adsorbents of ciprofloxacin (CPX) and tetracycline (TC) form alkaline aqueous media. The pillared clays obtained showed significant increases in their specific surface areas (SBET) and micropore volumes (Vμp) regarding the raw material, resulting in microporosity percentages higher than 57% in all materials. The studies of CPX and TC removal using pillared clays were compared with the natural clay and showed that the Si-PILC adsorption capacities have a strong relationship with their porous structures. The highest adsorption capacities were obtained for CPX on Si-PILC due to the lower molecular size of CPX respect to the TC molecule, favoring the interaction between the CPX− and the pillars adsorption sites. Tetracycline adsorption on silica pillared clays evidenced that for this molecule the porous structure limits the interaction between the TCH− and the pillars, decreasing their adsorption capacities. However, the results obtained for both antibiotics suggested that their negative species interact with adsorption sites on the pillared structure by adsorption mechanisms that involve inner-sphere complex formation as well as van der Waals interactions. The adsorption mechanism proposed for the anionic species on Si-PILC could be considered mainly as negative cooperative phenomena where firstly there is a hydrophobic effect followed by other interactions, such as der Waals or inner-sphere complex formation.

Protonation effects on dynamic flux properties of aqueous metal complexes

2009 ◽  
Vol 74 (10) ◽  
pp. 1543-1557 ◽  
Author(s):  
Herman P. Van Leeuwen ◽  
Raewyn M. Town
Keyword(s):  
Complex Formation ◽  
Metal Ion ◽  
Good Description ◽  
Minor Component ◽  
Outer Sphere ◽  
Metal Species ◽  
Central Metal ◽  
Inner Sphere ◽  
A Minor ◽  
Protonated Ligand

The degree of (de)protonation of aqueous metal species has significant consequences for the kinetics of complex formation/dissociation. All protonated forms of both the ligand and the hydrated central metal ion contribute to the rate of complex formation to an extent weighted by the pertaining outer-sphere stabilities. Likewise, the lifetime of the uncomplexed metal is determined by all the various protonated ligand species. Therefore, the interfacial reaction layer thickness, μ, and the ensuing kinetic flux, Jkin, are more involved than in the conventional case. All inner-sphere complexes contribute to the overall rate of dissociation, as weighted by their respective rate constants for dissociation, kd. The presence of inner-sphere deprotonated H2O, or of outer-sphere protonated ligand, generally has a great impact on kd of the inner-sphere complex. Consequently, the overall flux can be dominated by a species that is a minor component of the bulk speciation. The concepts are shown to provide a good description of experimental stripping chronopotentiometric data for several protonated metal–ligand systems.

Capillary isotachophoretic study of outer-sphere complex formation

1987 ◽  
Vol 23 (11) ◽  
pp. 811-813 ◽  
Author(s):  
S. Fanali ◽  
L. Ossicini ◽  
M. Sinibaldi
Keyword(s):  
Complex Formation ◽  
Outer Sphere ◽  
Outer Sphere Complex ◽  
Sphere Complex

Magnesium ion inner sphere complex in the anticodon loop of tRNAPhe

Biochemistry ◽  
1982 ◽  
Vol 21 (1) ◽  
pp. 49-53 ◽  
Author(s):  
Damian Labuda ◽  
Dietmar Poerschke
Keyword(s):  
Magnesium Ion ◽  
Anticodon Loop ◽  
Inner Sphere ◽  
Sphere Complex
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