| Autor: |
Zelenin, O., Kochergina, L., Ratnikov, S. |
| Zdroj: |
Russian Journal of Coordination Chemistry; July 2003, Vol. 29 Issue: 7 p478-483, 6p |
| Abstrakt: |
Complexation of the Ni2+ion with L-asparagine (HAsn±) is studied by potentiometric titration at 298.15 K and at the 0.3, 0.5 and 1.0 ionic strength of the solution (KNO3). The formation of the NiAsn+and NiAsn2complexes was established and their stability constants were determined. The thermodynamic stability constants of the mono- and bis(L-asparagine)nickel(II) complexes were obtained by extrapolation to zero ionic strength. The direct calorimetry method was used to measure the heat effect of the L-asparagine reaction with the Ni(II) nitrate solution in different pH intervals at 298.15 K and at the 0.5, 1.0, and 1.5 ionic strength (KNO3). The standard enthalpies of the NiAsn+and NiAsn2formation were found using extrapolation and the equation with one individual parameter. The enthalpies of the formation of the Ni(II) complexes with L-asparagine in aqueous solution were calculated in the standard hypothetically undissociated state. |
| Databáze: |
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