| Autor: |
Chatterjee, Debabrata, De, G S |
| Zdroj: |
Bulletin of the Chemical Society of Japan; July 1988, Vol. 61 Issue: 7 p2623-2628, 6p |
| Abstrakt: |
The kinetics of above titled reaction has been studied spectrophotometrically in various water–ethanol mixtures at different temperatures (45–60 °C). The following rate law has been established in the pH range 3.2 to 4.5.\fracd[Co(en)2(H2O)(LH)3+]dt=\frackaKE[Co(en)2(H2O)23+]T[LH]1+KE[LH]where LH represents the zwitterionic form of the amino acids viz. β-alanine and Dl-valine. KEis the ion-pair equilibrium constant between substrate complex ion and zwitterionic ligand the values of which increase with the increase of organic component of medium, where reverse is true for ka, the interchange rate constant from outersphere complex to innersphere product. It was observed that at higher ligand concentration a limiting rate is attained, which has been explained due to completion of ion-pair formation. Increasing effect of pH and special catalytic effect of NO3−have been observed. Activation parameters (ΔH\eweqand ΔS\eweq) have been calculated and compared with isotopic water exchange reaction and other deaquation reactions. A dissociative interchange mechanism (Id) involving ion-pair formation has been suggested. |
| Databáze: |
Supplemental Index |
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