Acetonitrile and Propionitrile Exchange at Palladium(II) and Platinum(II)
(1997) In Journal of the Chemical Society. Dalton Transactions 1997(24). p.4733-4737- Abstract
- Ligand exchange at square-planar [Pd(MeCN)4]2+ and [Pd(EtCN)4]2+ has been studied by 1H NMR line broadening and at [Pt(MeCN)4]2+ and [Pt(EtCN)4]2+ by isotopic labelling using 1H NMR spectroscopy in deuteriated nitromethane. Exchange takes place via two-term rate laws Rex/4 = (k1 + k2[RCN])cM with well defined k1 paths. Rate constants per co-ordination site k1298/s–1, k2298/kg mol–1 s–1 are 6.9 ± 1.6, 34 ± 3; 0.59 ± 0.12, 34 ± 3; 10.7 ± 1.8, 35 ± 4; (5.1 ± 2.3) × 10–6, (2.8 ± 0.2) × 10–5 and (5.5 ± 1.0) × 10–6, (3.3 ± 0.2) × 10–5 for [Pd(MeCN)4][CF3SO3]2, [Pd(MeCN)4][BF4]2, [Pd(EtCN)4][CF3SO3]2, [Pt(MeCN)4][CF3SO3]2 and [Pt(EtCN)4][CF3SO3]2, respectively. For [Pd(MeCN)4]2+ the k1 path is much larger for triflate than for tetrafluoroborate... (More)
- Ligand exchange at square-planar [Pd(MeCN)4]2+ and [Pd(EtCN)4]2+ has been studied by 1H NMR line broadening and at [Pt(MeCN)4]2+ and [Pt(EtCN)4]2+ by isotopic labelling using 1H NMR spectroscopy in deuteriated nitromethane. Exchange takes place via two-term rate laws Rex/4 = (k1 + k2[RCN])cM with well defined k1 paths. Rate constants per co-ordination site k1298/s–1, k2298/kg mol–1 s–1 are 6.9 ± 1.6, 34 ± 3; 0.59 ± 0.12, 34 ± 3; 10.7 ± 1.8, 35 ± 4; (5.1 ± 2.3) × 10–6, (2.8 ± 0.2) × 10–5 and (5.5 ± 1.0) × 10–6, (3.3 ± 0.2) × 10–5 for [Pd(MeCN)4][CF3SO3]2, [Pd(MeCN)4][BF4]2, [Pd(EtCN)4][CF3SO3]2, [Pt(MeCN)4][CF3SO3]2 and [Pt(EtCN)4][CF3SO3]2, respectively. For [Pd(MeCN)4]2+ the k1 path is much larger for triflate than for tetrafluoroborate as counter ion. Changing the tetrafluoroborate concentration has no effect on the exchange rate of acetonitrile at [Pd(MeCN)4]2+. In this case the k1 path is ascribed to an attack by solvent at the metal centre. For triflate saturation kinetics is observed. This can be rationalized in terms of ion-pair formation followed by reversible intramolecular exchange of nitrile for triflate within the ion pair, with an equilibrium constant Kip300 = 8 ± 2 kg mol–1 and a rate constant k300 = 12.5 ± 1.3 s–1. All activation entropies are negative, indicating associative activation. A new, simple one-step synthesis of the substrate complexes as their triflate salts, using [M(acac)2] (acac = acetylacetonate) as starting material, and of [Pd(MeCN)4][BF4]2 using palladium(II) acetate, is described. (Less)
- Abstract (Swedish)
- Ligand exchange at square-planar [Pd(MeCN)4]2+ and [Pd(EtCN)4]2+ has been studied by 1H NMR line broadening and at [Pt(MeCN)4]2+ and [Pt(EtCN)4]2+ by isotopic labelling using 1H NMR spectroscopy in deuteriated nitromethane. Exchange takes place via two-term rate laws Rex/4 = (k1 + k2[RCN])cM with well defined k1 paths. Rate constants per co-ordination site k1298/s–1, k2298/kg mol–1 s–1 are 6.9 ± 1.6, 34 ± 3; 0.59 ± 0.12, 34 ± 3; 10.7 ± 1.8, 35 ± 4; (5.1 ± 2.3) × 10–6, (2.8 ± 0.2) × 10–5 and (5.5 ± 1.0) × 10–6, (3.3 ± 0.2) × 10–5 for [Pd(MeCN)4][CF3SO3]2, [Pd(MeCN)4][BF4]2, [Pd(EtCN)4][CF3SO3]2, [Pt(MeCN)4][CF3SO3]2 and [Pt(EtCN)4][CF3SO3]2, respectively. For [Pd(MeCN)4]2+ the k1 path is much larger for triflate than for tetrafluoroborate... (More)
- Ligand exchange at square-planar [Pd(MeCN)4]2+ and [Pd(EtCN)4]2+ has been studied by 1H NMR line broadening and at [Pt(MeCN)4]2+ and [Pt(EtCN)4]2+ by isotopic labelling using 1H NMR spectroscopy in deuteriated nitromethane. Exchange takes place via two-term rate laws Rex/4 = (k1 + k2[RCN])cM with well defined k1 paths. Rate constants per co-ordination site k1298/s–1, k2298/kg mol–1 s–1 are 6.9 ± 1.6, 34 ± 3; 0.59 ± 0.12, 34 ± 3; 10.7 ± 1.8, 35 ± 4; (5.1 ± 2.3) × 10–6, (2.8 ± 0.2) × 10–5 and (5.5 ± 1.0) × 10–6, (3.3 ± 0.2) × 10–5 for [Pd(MeCN)4][CF3SO3]2, [Pd(MeCN)4][BF4]2, [Pd(EtCN)4][CF3SO3]2, [Pt(MeCN)4][CF3SO3]2 and [Pt(EtCN)4][CF3SO3]2, respectively. For [Pd(MeCN)4]2+ the k1 path is much larger for triflate than for tetrafluoroborate as counter ion. Changing the tetrafluoroborate concentration has no effect on the exchange rate of acetonitrile at [Pd(MeCN)4]2+. In this case the k1 path is ascribed to an attack by solvent at the metal centre. For triflate saturation kinetics is observed. This can be rationalized in terms of ion-pair formation followed by reversible intramolecular exchange of nitrile for triflate within the ion pair, with an equilibrium constant Kip300 = 8 ± 2 kg mol–1 and a rate constant k300 = 12.5 ± 1.3 s–1. All activation entropies are negative, indicating associative activation. A new, simple one-step synthesis of the substrate complexes as their triflate salts, using [M(acac)2] (acac = acetylacetonate) as starting material, and of [Pd(MeCN)4][BF4]2 using palladium(II) acetate, is described. (Less)
Please use this url to cite or link to this publication:
https://lup.lub.lu.se/record/11fdf28f-113b-4bee-90bf-2723f9f90825
- author
- Wendt, Ola LU ; N. F., Kaiser and Elding, Lars Ivar LU
- organization
- publishing date
- 1997-12-21
- type
- Contribution to journal
- publication status
- published
- subject
- keywords
- Palladium(II), Platinum(II), Acetonitrile, Propionitrile, Ligand exchange, Proton NMR line broadening, Reaction Mechanism, Actvation entropy, Triflate salt, Palladium(II), Platinum(II), Acetonitrile, Propionitrile, Ligand exchange, Kinetics, Reaction mechanism, NMR spectroscopy, Triflate salts
- in
- Journal of the Chemical Society. Dalton Transactions
- volume
- 1997
- issue
- 24
- pages
- 5 pages
- publisher
- Royal Society of Chemistry
- external identifiers
-
- scopus:33748828849
- ISSN
- 1472-7773
- DOI
- 10.1039/A705048H
- language
- English
- LU publication?
- yes
- id
- 11fdf28f-113b-4bee-90bf-2723f9f90825
- date added to LUP
- 2016-12-31 22:28:20
- date last changed
- 2022-01-30 08:59:19
@article{11fdf28f-113b-4bee-90bf-2723f9f90825, abstract = {{Ligand exchange at square-planar [Pd(MeCN)4]2+ and [Pd(EtCN)4]2+ has been studied by 1H NMR line broadening and at [Pt(MeCN)4]2+ and [Pt(EtCN)4]2+ by isotopic labelling using 1H NMR spectroscopy in deuteriated nitromethane. Exchange takes place via two-term rate laws Rex/4 = (k1 + k2[RCN])cM with well defined k1 paths. Rate constants per co-ordination site k1298/s–1, k2298/kg mol–1 s–1 are 6.9 ± 1.6, 34 ± 3; 0.59 ± 0.12, 34 ± 3; 10.7 ± 1.8, 35 ± 4; (5.1 ± 2.3) × 10–6, (2.8 ± 0.2) × 10–5 and (5.5 ± 1.0) × 10–6, (3.3 ± 0.2) × 10–5 for [Pd(MeCN)4][CF3SO3]2, [Pd(MeCN)4][BF4]2, [Pd(EtCN)4][CF3SO3]2, [Pt(MeCN)4][CF3SO3]2 and [Pt(EtCN)4][CF3SO3]2, respectively. For [Pd(MeCN)4]2+ the k1 path is much larger for triflate than for tetrafluoroborate as counter ion. Changing the tetrafluoroborate concentration has no effect on the exchange rate of acetonitrile at [Pd(MeCN)4]2+. In this case the k1 path is ascribed to an attack by solvent at the metal centre. For triflate saturation kinetics is observed. This can be rationalized in terms of ion-pair formation followed by reversible intramolecular exchange of nitrile for triflate within the ion pair, with an equilibrium constant Kip300 = 8 ± 2 kg mol–1 and a rate constant k300 = 12.5 ± 1.3 s–1. All activation entropies are negative, indicating associative activation. A new, simple one-step synthesis of the substrate complexes as their triflate salts, using [M(acac)2] (acac = acetylacetonate) as starting material, and of [Pd(MeCN)4][BF4]2 using palladium(II) acetate, is described.}}, author = {{Wendt, Ola and N. F., Kaiser and Elding, Lars Ivar}}, issn = {{1472-7773}}, keywords = {{Palladium(II); Platinum(II); Acetonitrile; Propionitrile; Ligand exchange; Proton NMR line broadening; Reaction Mechanism; Actvation entropy; Triflate salt; Palladium(II); Platinum(II); Acetonitrile; Propionitrile; Ligand exchange; Kinetics; Reaction mechanism; NMR spectroscopy; Triflate salts}}, language = {{eng}}, month = {{12}}, number = {{24}}, pages = {{4733--4737}}, publisher = {{Royal Society of Chemistry}}, series = {{Journal of the Chemical Society. Dalton Transactions}}, title = {{Acetonitrile and Propionitrile Exchange at Palladium(II) and Platinum(II)}}, url = {{http://dx.doi.org/10.1039/A705048H}}, doi = {{10.1039/A705048H}}, volume = {{1997}}, year = {{1997}}, }