A. Water Exchange 2326 B. Proton Exchange 2327 C. Electronic Relaxation 2327 D. Relaxivity 2331 E. Outerand Second-Sphere Relaxivity 2334 F. Methods of Improving Relaxivity 2336 V. Macromolecular Conjugates 2336 A. Introduction 2336 B. General Conjugation Methods 2336 C. Synthetic Linear Polymers 2336 D. Synthetic Dendrimer-Based Agents 2338 E. Naturally Occurring Polymers (Proteins, Polysaccharides, and Nucleic Acids) 2339

https://mriquestions.com/uploads/3/4/5/7/34572113/lauffer_1999_review.pdf

Gadolinium(III) Chelates as MRI Contrast Agents: Structure, Dynamics, and Applications

Lithium-ion batteries raise safety, environmental, and cost concerns, which mostly arise from their nonaqueous electrolytes. The use of aqueous alternatives is limited by their narrow electrochemical stability window (1.23 volts), which sets an intrinsic limit on the practical voltage and energy output. We report a highly concentrated aqueous electrolyte whose window was expanded to ~3.0 volts with the formation of an electrode-electrolyte interphase. A full lithium-ion battery of 2.3 volts using such an aqueous electrolyte was demonstrated to cycle up to 1000 times, with nearly 100% coulombic efficiency at both low (0.15 C) and high (4.5 C) discharge and charge rates.

"Water-in-salt" electrolyte enables high-voltage aqueous lithium-ion chemistries.

Artificial Organic Host Molecules for Anions

Structure and nanostructure in ionic liquids.

4. Structure of Ionic Hydration Shells 1351 4.1. Results from Diffraction Experiments 1351 4.1.1. X-ray Diffraction 1351 4.1.2. Neutron Diffraction 1351 4.2. Results from Computer Simulations 1352 4.3. Results from Spectroscopic Measurements 1354 4.3.1. Vibrational Spectroscopic Measurements 1354 4.3.2. EXAFS Spectroscopy 1354 4.3.3. NMR Relaxation Studies 1355 4.3.4. Dielectric Relaxation Studies 1355 4.4. Summary of the Structure of Ionic Hydration Shells 1355

Effect of ions on the structure of water: structure making and breaking.

The hydrolytic reactions of nickel(II) ion were studied at 25 °C in water and dioxane-water mixtures containing 3 M (Li)ClO4 as an ionic medium. Emf measurements were carried out in the range of the total nickel(II) ion concentration of 0.02469–0.7891 M in water, 0.02488–0.7996 M in a 0.1 mole fraction (35.21% w/w) dioxane-water mixture and 0.05170–0.9016 M in a 0.2 mole fraction (55.01% w/w) dioxane-water mixture, respectively. Some supplementary measurements were performed in a 0.5 mole fraction (83.02% w/w) dioxane-water mixture. Only the Ni4(OH)44+ complex was found in all solvent systems and its formation constant in log*β44 was −27.32±0.08 (in water), −27.11±0.08 (in a 0.1 mole fraction dioxane-water mixture), and −27.04±0.05 (in a 0.2 mole fraction dioxane-water mixture). In order to test the relative change of the formation consatnt of the Ni4(OH)44+ complex over the whole solvent composition examined, the variation of the formation constant was measured with the continual change of solvent compos...

Ionic Equilibria in Mixed Solvents. X. Hydrolysis of Nickel(II) Ion in Dioxane-Water Mixtures

Enthalpies of solution of some 1:1 and 2:1 electrolytes were determined in water and in a dioxane–water mixture (the dioxane content; 0.2 mole fraction or 55.0% w/w) by calorimetry at 25 °C. Enthalpies of transfer (ΔHto) of single ions from water to the dioxane–water mixture were obtained by employing the extrathermodynamic tetraphenylarsonium tetraphenylborate (TATB) assumption. Enthalpies of transfer of nickel(II) and copper(II) complexes with glycinate (gly−) and ethylenediamine (en) were also evaluated for [Ni(gly)n](2−n)+ (n=1–3), [Ni(en)n]2+(n=1–3), and [Cu(en)n]2+ (n=1–2) by combining enthalpies of transfer of the relevant single metal ions and ligands with enthalpies of complex formation reactions M+nL=MLn (M=Ni2+ or Cu2+ and L= gly− or en) in water and in the mixture. The enthalpies of transfer of the metal complexes examined here increased almost linearly with an increase in the number of the ligands within the complexes. The values of ΔHto of the ethylenediamine complexes of nickel(II) and copp...

Enthalpies of Transfer of Single Ions and Metal Complexes from Water to an Aqueous Dioxane Solution

The hydrolytic reaction of nickel ion was studied at 25°C in an aqueous 3M sodium chloride medium. In the range of the total nickel concentration of 0.0145–1.000M, the emf data obtained could be explained in terms of the formation of the complex Ni4(OH)4 (the charge is omitted), the formation constant of the species being found to be log*β4,4=−28.55±0.10, together with some minor species NiOH (log*β1,1≤−10.5) and Ni2OH(log*β1,2≤−10.5).

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Hydrolysis of Nickel(II) Ion in Aqueous 3M Sodium Chloride Medium

From X-ray scattering measurements on ammoniacal aqueous solutions of copper(II) chloride at the NH3/Cu mole ratios of 4.8 and 5.0, four ammonia molecules at the equatorial position and other two water molecules at the axial one were found to be coordinated to a copper(II) ion at the distance of 2.03 and 2.33 A, respectively. The radial distribution curve obtained for an aqueous solution of copper(II) chloride saturated with ammonia (NH3/Cu=11.2) showed that a higher ammine copper(II) complex than the tetraamminecopper(II) ion is formed in the solution. The complex has a distorted octahedral form in which the equatorial Cu–N bond distance is 1.93 A. The axial apices of the octahedron at the distance of 2.30 A are occupied by either an ammonia molecule and a water molecule or two ammonia molecules. The present study shows that the structures of the tetra- and higher-ammine copper(II) complexes in solution are different from those in crystal.

X-Ray Diffraction Studies on the Structures of Tetra- and Higherammine Complexes of Copper(II) Ion in Aqueous Solution

Equilibria between ethylenediamine and protons or nickel(II) ions have been investigated at 25 °C by means of potentiometric and calorimetric titrations in water and in dioxane–water mixtures (the dioxane contents are 0.1 and 0.2 mole fractions, which correspond to 35.2 and 55.0%w/w, respectively) containing 3 mol dm−3 LiClO4 as a constant ionic medium. Thermodynamic parameters (ΔG°, ΔH°, and ΔS°) referring to the formation of the species HL+, H2L2+, NiL2+, NiL22+, and NiL32+ (L denotes ethylenediamine) have been determined in the solutions. All the formation constants of the nickel(II)–ethylenediamine complexes increased with increasing dioxane content in the solvent mixtures, although the formation constants of the ethylenediammonium ions remained practically unchanged. On the other hand, enthalpies referring to the formation of the nickel(II)–ethylenediamine complexes became less negative, and thus entropies for the corresponding reactions increased remarkably with increasing dioxane content in the mix...

Hitoshi Ohtaki

Papers

Ionic Equilibria in Mixed Solvents. X. Hydrolysis of Nickel(II) Ion in Dioxane-Water Mixtures

Enthalpies of Transfer of Single Ions and Metal Complexes from Water to an Aqueous Dioxane Solution

Hydrolysis of Nickel(II) Ion in Aqueous 3M Sodium Chloride Medium

X-Ray Diffraction Studies on the Structures of Tetra- and Higherammine Complexes of Copper(II) Ion in Aqueous Solution

Potentiometric and Calorimetric Studies on the Formation of Ethylenediamine Complexes of Nickel(II) Ion in Water and Dioxane–Water Mixtures