Metal ion association in alcohol solutions. IV. Existence of an inner-sphere complex between erbium(III) and perchlorate

1974 ◽  
Vol 78 (19) ◽  
pp. 1940-1944 ◽  
Author(s):  
Herbert B. Silber
Keyword(s):  
Metal Ion ◽  
Ion Association ◽  
Inner Sphere ◽  
Sphere Complex

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.

Metal ion association in alcohol solutions—I

1974 ◽  
Vol 36 (1) ◽  
pp. 175-182 ◽  
Author(s):  
Jeffry Reidler ◽  
Herbert B. Silber
Keyword(s):  
Metal Ion ◽  
Ion Association

Solvent-dependent circular dichroism of trans-disubstituted Bis(R-propane-1,2-diamine)cobalt(III) complexes

1977 ◽  
Vol 30 (10) ◽  
pp. 2115 ◽  
Author(s):  
CJ Hawkins ◽  
GA Lawrance ◽  
RM Peachey
Keyword(s):  
Circular Dichroism ◽  
Metal Ion ◽  
Ion Association ◽  
Positive Contribution ◽  
Circular Dichroism Spectra ◽  
Hydrogen Bond Formation ◽  
Rotational Strength ◽  
Solvent Dependence ◽  
Halide Salts ◽  
Circular Dichroïsm

The circular dichroism spectra of trans-disubstituted bis(R-propane- 1,2-diamine)cobalt(III) complexes are reported for an extended series of solvents. The observed variations in the spectra of the dichloro and dibromo complexes are analysed in terms of stereoselective solvation at the diamine N-H protons, and also the ion association between the complexes and their counter-ions. The solvation of these dihalo complexes, which was studied by p.m.r., showed a preference for hydrogen-bond formation with the equatorial N-H protons, rendering the donor nitrogens asymmetric and thus introducing a new source of dissymmetry close to the metal ion chromophore. This affected a decrease in the positive rotational strength of the 1A1g → 1Eg (D4h) transition, and a positive contribution to the rotational strength of the 1A1g → 1A2g (D4h) component. Ion association of the dihalo complexes was evaluated by a comparison of the circular dichroism of the tetraphenylborate and halide salts. ��� The tendency for ion association was much greater for the tripositive diammine complex. However, stereospecific solvation was of little importance and the circular dichroism spectra did not show any marked solvent dependence for the tetraphenylborate salt.

scholarly journals When spectroscopy fails: The measurement of ion pairing

2006 ◽  
Vol 78 (8) ◽  
pp. 1571-1586 ◽  
Author(s):  
Glenn Hefter
Keyword(s):  
Metal Ion ◽  
Chemical Speciation ◽  
Ion Pairs ◽  
Ion Association ◽  
Ion Pair ◽  
Association Constants ◽  
Spectroscopic Techniques ◽  
Association Equilibria ◽  
Solvent Molecules ◽  
Contact Ion Pairs

Spectroscopic techniques such as UV/vis, NMR, and Raman are powerful tools for the investigation of chemical speciation in solution. However, it is not widely recognized that such techniques do not always provide reliable information about ion association equilibria. Specifically, spectroscopic measurements do not in general produce thermodynamically meaningful association constants for non-contact ion pairs, where the ions are separated by one or more solvent molecules. Such systems can only be properly quantified by techniques such as dielectric or ultrasonic relaxation, which can detect all ion-pair types (or equilibria), or by traditional thermodynamic methods, which detect the overall level of association. Various types of quantitative data are presented for metal ion/sulfate systems in aqueous solution that demonstrate the inadequacy of the major spectroscopic techniques for the investigation of systems that involve solvent-separated ion pairs. The implications for ion association equilibria in general are briefly discussed.

Outer-sphere and inner-sphere interactions in the formation of metal-ion nitrate complexes

1978 ◽  
Vol 23 (12) ◽  
pp. 1383-1386 ◽  
Author(s):  
Donald F.C. Morris ◽  
John D. MacCarthy ◽  
Robert J. Newton
Keyword(s):  
Metal Ion ◽  
Outer Sphere ◽  
Inner Sphere ◽  
Nitrate Complexes

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

Quantum chemical study of inner-sphere complexes of trivalent lanthanide and actinide ions on the corundum (110) surface

2013 ◽  
Vol 101 (9) ◽  
pp. 561-570
Author(s):  
R. Polly ◽  
B. Schimmelpfennig ◽  
M. Flörsheimer ◽  
Th. Rabung ◽  
T. Kupcik ◽  
...  
Keyword(s):  
Metal Ions ◽  
Density Functional ◽  
Single Point ◽  
Quantum Chemical Study ◽  
Basis Sets ◽  
Water Molecules ◽  
Point Energy ◽  
Inner Sphere ◽  
Sphere Complex ◽  
Inner Sphere Complexes

Summary Sorption plays a major role in the safety assessment of nuclear waste disposal. In the present theoretical study we focused on understanding the interaction of trivalent lanthanides and actinides (La3+, Eu3+ and Cm3+) with the corundum (110) surface. Optimization of the structures were carried out using density functional theory with different basis sets. Additionally, Møller-Plesset perturbation theory of second order was used for single point energy calculations. We studied the structure of different inner-sphere complexes depending on the surface deprotonation and the number of water molecules in the first coordination shell. The most likely structure of the inner-sphere complex (tri- or tetradentate) was predicted. For the calculations we used a cluster model for the surface. By deprotonating the cluster a chemical environment at elevated pH values was mimicked. Our calculations predict the highest stability for a tetradentate inner-sphere surface complexes with five water molecules remaining in the first coordination sphere of the metal ions. The formation of the inner-sphere complexes is favored when a coordination takes place with at most one deprotonated surface aluminol group located beneath the inner-sphere complex. The mutual interaction between sorbing metal ions at the surface is studied as well. The minimal possible distance between two inner-sphere sorbed metal ions at the surface was determined to be 530 pm.

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