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Platinum(IV) Bromo Aqua Complexes. Acid Hydrolysis Equilibria and Kinetics of Bromiide Anation

Elding, Lars Ivar LU and Gustafson, Lena (1971) In Inorganica Chimica Acta 5. p.643-649
Abstract (Swedish)
The stepwise stabililty constants, Kn for the bromo aqua complexes PtBrn−1(H2O)7−n5−n; n=4, 5, 6, formed in the successive acid hydrolyses of PtBr62−, have been determined to be K6=(.19±0.1) x 103 M−1, K5= (1.0±0.2) x 104 M−1 and K4=(1.1±0.2) x 105 M−1. A bromide assisted mechanism is proposed for the bromide anations of PtBr4(H2O)2 and PtBr5H2O-. Both these reactions are found to be first order with respect to platinum complex. The dependence of the observed rate constant on the bromide concentration can be described by the eqn.

kexp=κ′[Br−]+κ″[Br−]2

The last term is probably due to a reaction path via a bromide associated outer sphere complex, which might also be involved in the path described by the first term. A... (More)
The stepwise stabililty constants, Kn for the bromo aqua complexes PtBrn−1(H2O)7−n5−n; n=4, 5, 6, formed in the successive acid hydrolyses of PtBr62−, have been determined to be K6=(.19±0.1) x 103 M−1, K5= (1.0±0.2) x 104 M−1 and K4=(1.1±0.2) x 105 M−1. A bromide assisted mechanism is proposed for the bromide anations of PtBr4(H2O)2 and PtBr5H2O-. Both these reactions are found to be first order with respect to platinum complex. The dependence of the observed rate constant on the bromide concentration can be described by the eqn.

kexp=κ′[Br−]+κ″[Br−]2

The last term is probably due to a reaction path via a bromide associated outer sphere complex, which might also be involved in the path described by the first term. A spectrophotometric method has been used. To suppress the protolysis of the aqua complexes, 0.50 M perchloric acid was used as the ionic medium. The temperature was 25.0 °C. (Less)
Abstract
The stepwise stabililty constants, Kn for the bromo aqua complexes PtBrn−1(H2O)7−n5−n; n=4, 5, 6, formed in the successive acid hydrolyses of PtBr62−, have been determined to be K6=(.19±0.1) x 103 M−1, K5= (1.0±0.2) x 104 M−1 and K4=(1.1±0.2) x 105 M−1. A bromide assisted mechanism is proposed for the bromide anations of PtBr4(H2O)2 and PtBr5H2O-. Both these reactions are found to be first order with respect to platinum complex. The dependence of the observed rate constant on the bromide concentration can be described by the eqn.

kexp=κ′[Br−]+κ″[Br−]2

The last term is probably due to a reaction path via a bromide associated outer sphere complex, which might also be involved in the path described by the first term. A... (More)
The stepwise stabililty constants, Kn for the bromo aqua complexes PtBrn−1(H2O)7−n5−n; n=4, 5, 6, formed in the successive acid hydrolyses of PtBr62−, have been determined to be K6=(.19±0.1) x 103 M−1, K5= (1.0±0.2) x 104 M−1 and K4=(1.1±0.2) x 105 M−1. A bromide assisted mechanism is proposed for the bromide anations of PtBr4(H2O)2 and PtBr5H2O-. Both these reactions are found to be first order with respect to platinum complex. The dependence of the observed rate constant on the bromide concentration can be described by the eqn.

kexp=κ′[Br−]+κ″[Br−]2

The last term is probably due to a reaction path via a bromide associated outer sphere complex, which might also be involved in the path described by the first term. A spectrophotometric method has been used. To suppress the protolysis of the aqua complexes, 0.50 M perchloric acid was used as the ionic medium. The temperature was 25.0 °C. (Less)
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type
Contribution to journal
publication status
published
subject
keywords
Platinum(IV), Bromo-aqua complexes, Stability constants, Bromide anation, Kinetics, Bromide assisted substitution
in
Inorganica Chimica Acta
volume
5
pages
7 pages
publisher
Elsevier
external identifiers
  • scopus:25744465291
ISSN
0020-1693
DOI
10.1016/S0020-1693(00)96002-X
language
English
LU publication?
yes
id
40be3e9b-f1ad-475e-a7f7-67ec7fc8216f
date added to LUP
2017-02-19 19:36:53
date last changed
2017-11-14 09:54:54
@article{40be3e9b-f1ad-475e-a7f7-67ec7fc8216f,
  abstract     = {The stepwise stabililty constants, Kn for the bromo aqua complexes PtBrn−1(H2O)7−n5−n; n=4, 5, 6, formed in the successive acid hydrolyses of PtBr62−, have been determined to be K6=(.19±0.1) x 103 M−1, K5= (1.0±0.2) x 104 M−1 and K4=(1.1±0.2) x 105 M−1. A bromide assisted mechanism is proposed for the bromide anations of PtBr4(H2O)2 and PtBr5H2O-. Both these reactions are found to be first order with respect to platinum complex. The dependence of the observed rate constant on the bromide concentration can be described by the eqn.<br/><br/> kexp=κ′[Br−]+κ″[Br−]2<br/><br/>The last term is probably due to a reaction path via a bromide associated outer sphere complex, which might also be involved in the path described by the first term. A spectrophotometric method has been used. To suppress the protolysis of the aqua complexes, 0.50 M perchloric acid was used as the ionic medium. The temperature was 25.0 °C.},
  author       = {Elding, Lars Ivar and Gustafson, Lena},
  issn         = {0020-1693},
  keyword      = {Platinum(IV),Bromo-aqua complexes,Stability constants,Bromide anation,Kinetics,Bromide assisted substitution},
  language     = {eng},
  pages        = {643--649},
  publisher    = {Elsevier},
  series       = {Inorganica Chimica Acta},
  title        = {Platinum(IV) Bromo Aqua Complexes. Acid Hydrolysis Equilibria and Kinetics of Bromiide Anation},
  url          = {http://dx.doi.org/10.1016/S0020-1693(00)96002-X},
  volume       = {5},
  year         = {1971},
}