𝔖 Bobbio Scriptorium
✦   LIBER   ✦

Water exchange on magnesium(II) in aqueous solution: a variable temperature and pressure 17O NMR study

✍ Scribed by Anne Bleuzen; Pierre-André Pittet; Lothar Helm; André E. Merbach

Publisher
John Wiley and Sons
Year
1997
Tongue
English
Weight
385 KB
Volume
35
Category
Article
ISSN
0749-1581

No coin nor oath required. For personal study only.

✦ Synopsis

Fast water exchange rate constants on diamagnetic metal ions can be measured using either a paramagnetic chemical shift agent or a paramagnetic relaxation agent. An approximate analytical equation was developed for the chemical shift agent method, valid in the limit of rapid exchange. The limits of validity of these methods are discussed. These were applied to the study of water exchange on over a large temperature range [ Mg(H 2 O) ] 6 2' (252-350 K) and up to a pressure of 200 MPa by 17O NMR, leading to the following kinetic parameters : k Mg 298 = s-1 ; kJ mol-1 ; J K -1 ; c m 3 mol-1. 6.7 » 0.2 Â 105 DH Mg t = 49.1 » 0.7 DS Mg t = + 31.1 » 2.2 DV Mg t = + 6.7 » 0.7 From these data, it is concluded that this process has an mechanism with strong d character, without excluding a I d limiting D mechanism.

📜 SIMILAR VOLUMES

Water-Exchange Mechanism of Tetraaquapal
Water-Exchange Mechanism of Tetraaquapalladium(II). A Variable-Pressure and Variable-Temperature Oxygen-17 NMR Study
✍ Lothar Helm; Lars I. Elding; André E. Merbach 📂 Article 📅 1984 🏛 John Wiley and Sons 🌐 German ⚖ 404 KB

Water exchange of square-planar Pd(H,O):' has been studied as a function of temperature (240 to 345 K) and pressure (0.1 to 260 MPa, at 324 K) by measuring the I70-FT-NMR line-widths of the resonance from coordinated water at 27.11 and 48.78 MHz. The following exchange parameters were obtained: k:&8

High-Pressure 17O-NMR. Study of Vanadium
High-Pressure 17O-NMR. Study of Vanadium (II) in Water: A Second Example of an Associative Interchange Mechanism (Ia) for Solvent Exchange on an Octahedral Divalent Transition-Metal Ion
✍ Yves Ducommun; Donald Zbinden; André E. Murbach 📂 Article 📅 1982 🏛 John Wiley and Sons 🌐 German ⚖ 312 KB

## Abstract The water exchange of [V(H~2~O)~6~]Cl~2~ in aqueous solution has been studied as a function of temperature and pressure (up to 250 MPa), by measuring the ^17^O‐FT‐NMR. line‐widths of the free water resonance at 8.13 MHz. The kinetic parameters obtained are __K__ = 87±4 s^−1^, __ΔH__^\*^

Thermodynamic origin of cis/trans isomer
Thermodynamic origin of cis/trans isomers of a proline-containing β-turn model dipeptide in aqueous solution: A combined variable temperature 1H-NMR, two-dimensional 1H,1H gradient enhanced nuclear overhauser effect spectroscopy (NOESY), one-dimensional steady-state intermolecular 13C,1H NOE, and molecular dynamics study
✍ Anastasios Troganis; Ioannis P. Gerothanassis; Zafiria Athanassiou; Thomas Mavro 📂 Article 📅 2000 🏛 Wiley (John Wiley & Sons) 🌐 English ⚖ 178 KB 👁 1 views

The cis/trans conformational equilibrium of the two Ac-Pro isomers of the beta-turn model dipeptide [13C]-Ac-L-Pro-D-Ala-NHMe, 98% 13C enriched at the acetyl carbonyl atom, was investigated by the use of variable temperature gradient enhanced 1H-nmr, two-dimensional (2D) 1H,1H nuclear Overhauser eff