ISSN:
0749-1581
Keywords:
17O NMR
;
mixed ligands
;
bound water
;
aqueous solutions of amino acids and CO(II)
;
Chemistry
;
Analytical Chemistry and Spectroscopy
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
The effect of mixed ligands on the lifetime and 17O hyperfine coupling constant of water bound to Co2+ in aqueous solutions of proline, glycine and alanine was determined, as a function of pH, by means of 17O NMR. The lifetime of the coordinated water molecules decreased from 4.9 X 10-7 s (for the pure aqueous complex) to 3.5 × 10-8 at pH 8, where more than one complex of proline were present. Smaller changes were measured for the 17O hyperfine coupling constant of water [from - 1.7 × 107 Hz for Co(H2O)62+ to -1.45 × 107 Hz measured at pH 6 in the presence of proline], and the enthalpy of activation of the first-order exchange from the first coordination sphere of Co2+ (from 7.4 ± 0.2 kcal mol-1 for the pure aqueous complex to 6.2 ± 0.4 kcal mol-1 at pH 8 in the presence of proline).
Additional Material:
9 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/mrc.1260250505
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