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Indian Journal of Chemistry -Section A (IJC-A) >
IJC-A Vol.46A [2007] >
IJC-A Vol.46A(04) [April 2007] >
| Title: | Kinetic studies of substitution on [(H₂O)(tap) ₂RuORu(tap)₂(H₂O)]²⁺ ion by DL-penicillamine at physiological pH |
| Authors: | Ghosh, Alak Kumar |
| Issue Date: | Apr-2007 |
| Publisher: | CSIR |
| Abstract: | The reaction of DL-penicillamine with the title complex has been studied spectrophotometrically in aqueous solution as a function of concentrations of the substrate complex and ligand, pH and temperature. The reactivity of different donor centers
[i.e., (N), (N,O) and (O,O)] have been compared. At pH 7.4 the reaction is a two-step process. Unlike other systems studied with the same substrate, the second step in the present case is ligand independent, ascribed to the lower difference between the two steps (k₁ = 1.78×10⁻³ s1and k₂ = 0.67×10⁻⁴ s⁻¹ respectively at 50°C) in comparison to the other systems studied earlier (k₁~10⁻³s⁻¹ and k₂~10⁻⁵s⁻¹). An associative interchange mechanism is proposed for both the steps. The activation parameters (ΔH₁ = 19.2 ± 1 kJ mol⁻¹, ΔS₁ = -239 ± 3 JK⁻¹ mol⁻¹; ΔH₂ = 65.6 ± 5.8 kJ mol⁻¹ and ΔS₂ = 123 ± 17 JK⁻¹ mol⁻¹) support the proposition. The activation parameters have been compared with other systems studied earlier. |
| Page(s): | 610-614 |
| ISSN: | 0376-4710 |
| Source: | IJC-A Vol.46A(04) [April 2007]
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