The kinetics and thermodynamics of a novel efficient mixed water–1,4-dioxan solvent for the effective complexation of a neutral ruthenium complex with carbon monoxide at atmospheric pressure
✍ Scribed by Ram S. Shukla; Vivek K. Srivastava; Munir D. Khokhar; Raksh V. Jasra
- Publisher
- John Wiley and Sons
- Year
- 2008
- Tongue
- English
- Weight
- 252 KB
- Volume
- 40
- Category
- Article
- ISSN
- 0538-8066
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✦ Synopsis
Abstract
Kinetic and thermodynamic investigations were performed for a mixed aqueous‐organic, 1:1 (v/v) water–1,4‐dioxane medium, which was found to be an efficient solvent for the interaction of a neutral dichlorotris(triphenylphosphine) ruthenium(II), RuCl~2~(PPh~3~)~3~ complex with carbon monoxide at atmospheric pressure. During the interaction, RuCl~2~(PPh~3~)~3~ dissociates to a neutral complex dichlorobis(triphenylphosphine) ruthenium(II), RuCl~2~(PPh~3~)~2~, by losing a coordinated PPh~3~ ligand and RuCl~2~(PPh~3~)~2~ coordinates with CO to form an in situ carbonyl complex RuCl~2~(CO)(PPh~3~)~2~. The in situ formed carbonyl complex RuCl~2~(CO)(PPh~3~)~2~ was thoroughly characterized by equilibrium, spectrophotometric, IR, and electrochemical techniques. Under equilibrium conditions, the rate and dissociation constants for the dissociation of PPh~3~ from RuCl~2~(PPh~3~)~3~ were found to be favorable for the formation of the carbonyl complex RuCl~2~(CO)(PPh~3~)~2~. The rates of complexation for the formation of RuCl~2~(CO)(PPh~3~)~2~ were found to follow an overall second‐order kinetics being first order in terms of the concentrations of both carbon monoxide and RuCl~2~(PPh~3~)~2~. The determined activation parameters corresponding to the rate constant (ΔH^#^ = 35.9 ± 2.5 kJ mol^−1^ and ΔS^#^ = −122 ± 6 J K^−1^ mol^−1^) and thermodynamic parameters corresponding to the formation constant (ΔH° = −33.5 ± 4.5 kJ mol^−1^, ΔS° = −25 ± 8 J K^−1^ mol^−1^, and ΔG° = −25.7 ± 2.0 kJ mol^−1^) were found to be highly favorable for the formation of the complex RuCl2(CO)(PPh3)2. © 2008 Wiley Periodicals, Inc. Int J Chem Kinet 40: 359–369, 2008