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Bromide Anation Kinetics of Some Platinum(IV) Bromo Aqua Complexes

Elding, Lars Ivar LU and Gustafson, Lena (1977) In Inorganica Chimica Acta 22(2). p.201-207
Abstract (Swedish)
Bromide anations of PtBr5H2O− in the presence of PtBr42− or bromine, of trans-PtBr4(H2O)2 in the presence of PtBr42− and of cis-PtBr4(H2O)2 in the presence of bromine have been studied in 0.50 M perchloric acid medium at 25 °C.

The rate law for the bromide anation of PtBr5H2O−indicates two parallel reaction paths. The term k′Br−2 corresponds to a bromide assisted mechanism. The second term in the rate expression can be accounted for by assuming that a dimeric intermediate is formed from the platinum(IV) substrate and hydrated PtBr42−. The formation of the reaction product PtBr62− is preceded by a substitution of water by bromide in this dimer.

A bromide assisted mechanism can also describe the bromide anation kinetics of... (More)
Bromide anations of PtBr5H2O− in the presence of PtBr42− or bromine, of trans-PtBr4(H2O)2 in the presence of PtBr42− and of cis-PtBr4(H2O)2 in the presence of bromine have been studied in 0.50 M perchloric acid medium at 25 °C.

The rate law for the bromide anation of PtBr5H2O−indicates two parallel reaction paths. The term k′Br−2 corresponds to a bromide assisted mechanism. The second term in the rate expression can be accounted for by assuming that a dimeric intermediate is formed from the platinum(IV) substrate and hydrated PtBr42−. The formation of the reaction product PtBr62− is preceded by a substitution of water by bromide in this dimer.

A bromide assisted mechanism can also describe the bromide anation kinetics of cis-PtBr4(H2O)2, the rate law determined. The bromide anation of trans-PtBr4(H2O)2 in the presence of PtBr42− occurs by a two-term rate law, indicating two parallel paths, k′ corresponding to formation of PtBr5H2O− and k″ to formation of PtBr62−.

Trans-PtBr4(H2O)2 reacts so slowly with bromide in the absence of PtBr42− that no reaction can be observed. The large difference in bromide anation rates for PtBr5H2O− and cis-PtBr4(H2O)2 compared to trans-PtBr4(H2O)2 might indicate that halide assisted anations are possible only for complexes having a halide (or some other effective bridging group) in trans-position to the aqua ligand to be replaced. (Less)
Abstract
Bromide anations of PtBr5H2O− in the presence of PtBr42− or bromine, of trans-PtBr4(H2O)2 in the presence of PtBr42− and of cis-PtBr4(H2O)2 in the presence of bromine have been studied in 0.50 M perchloric acid medium at 25 °C.
The rate law for the bromide anation of PtBr5H2O−indicates two parallel reaction paths. The term k′Br−2 corresponds to a bromide assisted mechanism. The second term in the rate expression can be accounted for by assuming that a dimeric intermediate is formed from the platinum(IV) substrate and hydrated PtBr42−. The formation of the reaction product PtBr62− is preceded by a substitution of water by bromide in this dimer.
A bromide assisted mechanism can also describe the bromide anation kinetics... (More)
Bromide anations of PtBr5H2O− in the presence of PtBr42− or bromine, of trans-PtBr4(H2O)2 in the presence of PtBr42− and of cis-PtBr4(H2O)2 in the presence of bromine have been studied in 0.50 M perchloric acid medium at 25 °C.
The rate law for the bromide anation of PtBr5H2O−indicates two parallel reaction paths. The term k′Br−2 corresponds to a bromide assisted mechanism. The second term in the rate expression can be accounted for by assuming that a dimeric intermediate is formed from the platinum(IV) substrate and hydrated PtBr42−. The formation of the reaction product PtBr62− is preceded by a substitution of water by bromide in this dimer.
A bromide assisted mechanism can also describe the bromide anation kinetics of cis-PtBr4(H2O)2, the rate law determined. The bromide anation of trans-PtBr4(H2O)2 in the presence of PtBr42− occurs by a two-term rate law, indicating two parallel paths, k′ corresponding to formation of PtBr5H2O− and k″ to formation of PtBr62−.
Trans-PtBr4(H2O)2 reacts so slowly with bromide in the absence of PtBr42− that no reaction can be observed. The large difference in bromide anation rates for PtBr5H2O− and cis-PtBr4(H2O)2 compared to trans-PtBr4(H2O)2 might indicate that halide assisted anations are possible only for complexes having a halide (or some other effective bridging group) in trans-position to the aqua ligand to be replaced. (Less)
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organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
Platinum(IV), Bromide anation, Kinetics, Reaction mechanism, Bromide assisted substitution
in
Inorganica Chimica Acta
volume
22
issue
2
pages
7 pages
publisher
Elsevier
external identifiers
  • scopus:4243404116
ISSN
0020-1693
DOI
10.1016/S0020-1693(00)90919-8
language
English
LU publication?
yes
id
b3f84f25-a447-4bd0-8c67-b34c9825ae38
date added to LUP
2017-02-19 16:51:58
date last changed
2017-11-14 09:52:56
@article{b3f84f25-a447-4bd0-8c67-b34c9825ae38,
  abstract     = {Bromide anations of PtBr5H2O− in the presence of PtBr42− or bromine, of trans-PtBr4(H2O)2 in the presence of PtBr42− and of cis-PtBr4(H2O)2 in the presence of bromine have been studied in 0.50 M perchloric acid medium at 25 °C.<br/>       The rate law for the bromide anation of PtBr5H2O−indicates two parallel reaction paths. The term k′Br−2 corresponds to a bromide assisted mechanism. The second term in the rate expression can be accounted for by assuming that a dimeric intermediate is formed from the platinum(IV) substrate and hydrated PtBr42−. The formation of the reaction product PtBr62− is preceded by a substitution of water by bromide in this dimer.<br/>      A bromide assisted mechanism can also describe the bromide anation kinetics of cis-PtBr4(H2O)2, the rate law determined. The bromide anation of trans-PtBr4(H2O)2 in the presence of PtBr42− occurs by a two-term rate law,  indicating two parallel paths, k′ corresponding to formation of PtBr5H2O− and k″ to formation of PtBr62−.<br/>      Trans-PtBr4(H2O)2 reacts so slowly with bromide in the absence of PtBr42− that no reaction can be observed. The large difference in bromide anation rates for PtBr5H2O− and cis-PtBr4(H2O)2 compared to trans-PtBr4(H2O)2 might indicate that halide assisted anations are possible only for complexes having a halide (or some other effective bridging group) in trans-position to the aqua ligand to be replaced.},
  author       = {Elding, Lars Ivar and Gustafson, Lena},
  issn         = {0020-1693},
  keyword      = {Platinum(IV),Bromide anation,Kinetics,Reaction mechanism,Bromide assisted substitution},
  language     = {eng},
  number       = {2},
  pages        = {201--207},
  publisher    = {Elsevier},
  series       = {Inorganica Chimica Acta},
  title        = {Bromide Anation Kinetics of Some Platinum(IV) Bromo Aqua Complexes},
  url          = {http://dx.doi.org/10.1016/S0020-1693(00)90919-8},
  volume       = {22},
  year         = {1977},
}