Kinetic and mechanistic investigation of the substitution reactions of four and five co-ordinated rhodium stibine complexes with a bulky phosphite
(2013) In Dalton Transactions 42(39). p.14134-14139- Abstract
- The substitution reaction of trans-[Rh(Cl)(CO)(SbPh3)(2)] (1) with tris(2,4-di-tert-butylphenyl)phosphite (2,4-TBPP) to form trans-[Rh(Cl)(CO)(2,4-TBPP)(2)] (4) in two consecutive steps has been investigated by UV-vis stopped-flow spectrophotometry. The experiments were performed in dichloromethane and in ethyl acetate, at 298 K and 268 K respectively for the first reaction step, and for the second reaction step over a temperature range from 278 to 313 K in both solvents. The first step is very fast (up to 1630 s(-1)) and on the limit of what is observable with the stopped-flow technique. Introduction of the five-coordinate complex trans-[Rh(Cl)(CO)(SbPh3)(3)] (2) in equilibrium with (1), by adding an excess SbPh3, led to a significant... (More)
- The substitution reaction of trans-[Rh(Cl)(CO)(SbPh3)(2)] (1) with tris(2,4-di-tert-butylphenyl)phosphite (2,4-TBPP) to form trans-[Rh(Cl)(CO)(2,4-TBPP)(2)] (4) in two consecutive steps has been investigated by UV-vis stopped-flow spectrophotometry. The experiments were performed in dichloromethane and in ethyl acetate, at 298 K and 268 K respectively for the first reaction step, and for the second reaction step over a temperature range from 278 to 313 K in both solvents. The first step is very fast (up to 1630 s(-1)) and on the limit of what is observable with the stopped-flow technique. Introduction of the five-coordinate complex trans-[Rh(Cl)(CO)(SbPh3)(3)] (2) in equilibrium with (1), by adding an excess SbPh3, led to a significant decrease in overall reaction rate for the formation of the intermediate trans-[Rh(Cl)-(CO)(SbPh3)(2)(2,4-TBPP)] (3). Activation parameters for the second substitution reaction, in which 3 is converted to 4, has been determined as Delta H double dagger = 22.85 +/- 0.17 and 28.38 +/- 0.10 kJ mol(-1) and Delta S double dagger = - 144.7 +/- 0.6 and -100.9 +/- 0.4 J mol(-1) K-1 for CH2Cl2 and EtOAc respectively, supporting an associative pathway. A strongly coordinating solvent promotes both reactions. In all reaction steps a strong tendency for stibines to promote 5-coordinated, fairly stable intermediates is manifested. (Less)
Please use this url to cite or link to this publication:
https://lup.lub.lu.se/record/4171563
- author
- Hennion, Clare ; Jonasson, Klara LU ; Wendt, Ola LU and Roodt, Andreas
- organization
- publishing date
- 2013
- type
- Contribution to journal
- publication status
- published
- subject
- in
- Dalton Transactions
- volume
- 42
- issue
- 39
- pages
- 14134 - 14139
- publisher
- Royal Society of Chemistry
- external identifiers
-
- wos:000324751100013
- scopus:84884252585
- pmid:23942428
- ISSN
- 1477-9234
- DOI
- 10.1039/c3dt51757h
- language
- English
- LU publication?
- yes
- id
- 72a2cdfd-51ce-4dbb-8bac-e938a7ebb5f9 (old id 4171563)
- date added to LUP
- 2016-04-01 10:34:39
- date last changed
- 2022-01-26 00:33:56
@article{72a2cdfd-51ce-4dbb-8bac-e938a7ebb5f9,
abstract = {{The substitution reaction of trans-[Rh(Cl)(CO)(SbPh3)(2)] (1) with tris(2,4-di-tert-butylphenyl)phosphite (2,4-TBPP) to form trans-[Rh(Cl)(CO)(2,4-TBPP)(2)] (4) in two consecutive steps has been investigated by UV-vis stopped-flow spectrophotometry. The experiments were performed in dichloromethane and in ethyl acetate, at 298 K and 268 K respectively for the first reaction step, and for the second reaction step over a temperature range from 278 to 313 K in both solvents. The first step is very fast (up to 1630 s(-1)) and on the limit of what is observable with the stopped-flow technique. Introduction of the five-coordinate complex trans-[Rh(Cl)(CO)(SbPh3)(3)] (2) in equilibrium with (1), by adding an excess SbPh3, led to a significant decrease in overall reaction rate for the formation of the intermediate trans-[Rh(Cl)-(CO)(SbPh3)(2)(2,4-TBPP)] (3). Activation parameters for the second substitution reaction, in which 3 is converted to 4, has been determined as Delta H double dagger = 22.85 +/- 0.17 and 28.38 +/- 0.10 kJ mol(-1) and Delta S double dagger = - 144.7 +/- 0.6 and -100.9 +/- 0.4 J mol(-1) K-1 for CH2Cl2 and EtOAc respectively, supporting an associative pathway. A strongly coordinating solvent promotes both reactions. In all reaction steps a strong tendency for stibines to promote 5-coordinated, fairly stable intermediates is manifested.}},
author = {{Hennion, Clare and Jonasson, Klara and Wendt, Ola and Roodt, Andreas}},
issn = {{1477-9234}},
language = {{eng}},
number = {{39}},
pages = {{14134--14139}},
publisher = {{Royal Society of Chemistry}},
series = {{Dalton Transactions}},
title = {{Kinetic and mechanistic investigation of the substitution reactions of four and five co-ordinated rhodium stibine complexes with a bulky phosphite}},
url = {{http://dx.doi.org/10.1039/c3dt51757h}},
doi = {{10.1039/c3dt51757h}},
volume = {{42}},
year = {{2013}},
}