Stabilities, Solubility and Kinetics and Mechanism for Formation and Hydrolysis of some Palladium(II) and Platinum(II) Iodo Complexes in Aqueous Solution
(1986) In Inorganica Chimica Acta 117(1). p.9-16- Abstract
- Complex formation between Pd(II), Pt(II) and iodide has been studied at 25 °C for an aqueous 1.00 M perchloric acid medium. Measurements of the solubility of PdI2(s) in aqueous mercury(II) perchlorate and of AgI(s) and PdI2(s) in aqueous solutions of Pd2+(aq) and Ag+(aq) gave the solubility product of PdI2(s) as Kso=(7±3) × 10−32 M3, which is much smaller than previous literature values.
The stability constants β1=[MI(H2O)3+]/([M(H2O)42+][I−]) for the two systems were obtained as the ratio between rate constants for the forward and reverse reactions.
The following values of k1 (s−1 M−1), k−1 (s−1) and β1 (M−1) were obtained at 25 °C: (1.14±0.11) × 106, (0.92±0.18), (12±4) × 105 for MPd, and (7.7±0.4), (8.0±0.7) × 10−5,... (More) - Complex formation between Pd(II), Pt(II) and iodide has been studied at 25 °C for an aqueous 1.00 M perchloric acid medium. Measurements of the solubility of PdI2(s) in aqueous mercury(II) perchlorate and of AgI(s) and PdI2(s) in aqueous solutions of Pd2+(aq) and Ag+(aq) gave the solubility product of PdI2(s) as Kso=(7±3) × 10−32 M3, which is much smaller than previous literature values.
The stability constants β1=[MI(H2O)3+]/([M(H2O)42+][I−]) for the two systems were obtained as the ratio between rate constants for the forward and reverse reactions.
The following values of k1 (s−1 M−1), k−1 (s−1) and β1 (M−1) were obtained at 25 °C: (1.14±0.11) × 106, (0.92±0.18), (12±4) × 105 for MPd, and (7.7±0.4), (8.0±0.7) × 10−5, (9.6±1.3) × 104 for MPt. Combination with previous literature data gives the following values of log(β1 (M−1)) to log(β4 (M−4)): 6.08, ∼22, 25.8 and 28.3 for MPd, and 4.98, ∼25, ∼28, and ∼30 for MPt. The present results show that the large overall stability constants β4 observed for the M2+I− systems are most likely due to a very large stability of the second complex MI2(H2O)2, which is probably a cis-isomer. A distinct plateau in the formation curve for mean ligand number 2 is obtained both for MPd and Pt. The other iodo complexes are not especially stable compared to those of chloride and bromide.
ΔH≠ (kJ mol−1) and ΔS≠ (JK−1 mol−1) for the forward reaction of (i), MPd, are (17.3±1.7) and (−71±5), and for the reverse reaction of (i) MPd, (45±3) and (−95±6), respectively. The kinetics are compatible with associative activation (Ia). The contribution from bond-breaking in the formation of the transition state seems to be less important for Pd than for Pt. (Less) - Abstract (Swedish)
- Complex formation between Pd(II), Pt(II) and iodide has been studied at 25 °C for an aqueous 1.00 M perchloric acid medium. Measurements of the solubility of PdI2(s) in aqueous mercury(II) perchlorate and of AgI(s) and PdI2(s) in aqueous solutions of Pd2+(aq) and Ag+(aq) gave the solubility product of PdI2(s) as Kso=(7±3) × 10−32 M3, which is much smaller than previous literature values.
The stability constants β1=[MI(H2O)3+]/([M(H2O)42+][I−]) for the two systems were obtained as the ratio between rate constants for the forward and reverse reactions. The following values of k1 (s−1 M−1), k−1 (s−1) and β1 (M−1) were obtained at 25 °C: (1.14±0.11) × 106, (0.92±0.18), (12±4) × 105 for M=Pd, and (7.7±0.4), (8.0±0.7) × 10−5, (9.6±1.3)... (More) - Complex formation between Pd(II), Pt(II) and iodide has been studied at 25 °C for an aqueous 1.00 M perchloric acid medium. Measurements of the solubility of PdI2(s) in aqueous mercury(II) perchlorate and of AgI(s) and PdI2(s) in aqueous solutions of Pd2+(aq) and Ag+(aq) gave the solubility product of PdI2(s) as Kso=(7±3) × 10−32 M3, which is much smaller than previous literature values.
The stability constants β1=[MI(H2O)3+]/([M(H2O)42+][I−]) for the two systems were obtained as the ratio between rate constants for the forward and reverse reactions. The following values of k1 (s−1 M−1), k−1 (s−1) and β1 (M−1) were obtained at 25 °C: (1.14±0.11) × 106, (0.92±0.18), (12±4) × 105 for M=Pd, and (7.7±0.4), (8.0±0.7) × 10−5, (9.6±1.3) × 104 for M=Pt. Combination with previous literature data gives the following values of log(β1 (M−1)) to log(β4 (M−4)): 6.08, ∼22, 25.8 and 28.3 for M=Pd, and 4.98, ∼25, ∼28, and ∼30 for M=Pt. The present results show that the large overall stability constants β4 observed for the M2+ + I− systems are most likely due to a very large stability of the second complex MI2(H2O)2, which is probably a cis-isomer. A distinct plateau in the formation curve for mean ligand number 2 is obtained both for M=Pd and Pt. The other iodo complexes are not especially stable compared to those of chloride and bromide.
ΔH≠ (kJ mol−1) and ΔS≠ (JK−1 mol−1) for the forward reaction of (i), M=Pd, are (17.3±1.7) and (−71±5), and for the reverse reaction of (i) M=Pd, (45±3) and (−95±6), respectively. The kinetics are compatible with associative activation (Ia). The contribution from bond-breaking in the formation of the transition state seems to be less important for Pd than for Pt. (Less)
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- author
- Elding, Lars Ivar LU and Olsson, Lars Fride
- organization
- publishing date
- 1986
- type
- Contribution to journal
- publication status
- published
- subject
- keywords
- Gold(III), Iodide, Palladium(II), Platinum(II), Complex formation, Solubility, Thermodynamic stability, Kinetiks, Reaction mechanism, Pd/Pt comparison, Palladium(II), Platinum(II), Iodide, Complex formation, Stabilities, Kinetics, Reaction mechanism
- in
- Inorganica Chimica Acta
- volume
- 117
- issue
- 1
- pages
- 9 - 16
- publisher
- Elsevier
- external identifiers
-
- scopus:0039615558
- ISSN
- 0020-1693
- DOI
- 10.1016/S0020-1693(00)88059-7
- language
- English
- LU publication?
- yes
- id
- c3e7c6a7-d804-41bb-b3ef-cb6f4d97310d
- date added to LUP
- 2017-01-11 19:10:26
- date last changed
- 2021-09-26 05:19:16
@article{c3e7c6a7-d804-41bb-b3ef-cb6f4d97310d, abstract = {{Complex formation between Pd(II), Pt(II) and iodide has been studied at 25 °C for an aqueous 1.00 M perchloric acid medium. Measurements of the solubility of PdI2(s) in aqueous mercury(II) perchlorate and of AgI(s) and PdI2(s) in aqueous solutions of Pd2+(aq) and Ag+(aq) gave the solubility product of PdI2(s) as Kso=(7±3) × 10−32 M3, which is much smaller than previous literature values.<br/>The stability constants β1=[MI(H2O)3+]/([M(H2O)42+][I−]) for the two systems were obtained as the ratio between rate constants for the forward and reverse reactions.<br/><br/>The following values of k1 (s−1 M−1), k−1 (s−1) and β1 (M−1) were obtained at 25 °C: (1.14±0.11) × 106, (0.92±0.18), (12±4) × 105 for MPd, and (7.7±0.4), (8.0±0.7) × 10−5, (9.6±1.3) × 104 for MPt. Combination with previous literature data gives the following values of log(β1 (M−1)) to log(β4 (M−4)): 6.08, ∼22, 25.8 and 28.3 for MPd, and 4.98, ∼25, ∼28, and ∼30 for MPt. The present results show that the large overall stability constants β4 observed for the M2+I− systems are most likely due to a very large stability of the second complex MI2(H2O)2, which is probably a cis-isomer. A distinct plateau in the formation curve for mean ligand number 2 is obtained both for MPd and Pt. The other iodo complexes are not especially stable compared to those of chloride and bromide.<br/><br/>ΔH≠ (kJ mol−1) and ΔS≠ (JK−1 mol−1) for the forward reaction of (i), MPd, are (17.3±1.7) and (−71±5), and for the reverse reaction of (i) MPd, (45±3) and (−95±6), respectively. The kinetics are compatible with associative activation (Ia). The contribution from bond-breaking in the formation of the transition state seems to be less important for Pd than for Pt.}}, author = {{Elding, Lars Ivar and Olsson, Lars Fride}}, issn = {{0020-1693}}, keywords = {{Gold(III); Iodide; Palladium(II); Platinum(II); Complex formation; Solubility; Thermodynamic stability; Kinetiks; Reaction mechanism; Pd/Pt comparison; Palladium(II); Platinum(II); Iodide; Complex formation; Stabilities; Kinetics; Reaction mechanism}}, language = {{eng}}, number = {{1}}, pages = {{9--16}}, publisher = {{Elsevier}}, series = {{Inorganica Chimica Acta}}, title = {{Stabilities, Solubility and Kinetics and Mechanism for Formation and Hydrolysis of some Palladium(II) and Platinum(II) Iodo Complexes in Aqueous Solution}}, url = {{http://dx.doi.org/10.1016/S0020-1693(00)88059-7}}, doi = {{10.1016/S0020-1693(00)88059-7}}, volume = {{117}}, year = {{1986}}, }