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Synthesis, Structure, and Reactivity of Arylchlorobis(dialkyl sulfide)platinum(II) Complexes

Wendt, Ola LU ; Oskarsson, Åke LU ; Leipoldt, Johann G. and Elding, Lars Ivar LU (1997) In Inorganic Chemistry 1997(36). p.4514-4519
Abstract (Swedish)
Complexes trans-[PtRCl(SR‘2)2], where R = Ph, mesityl, and p-anisyl and R‘ = Me or Et, have been synthesized and their crystal and molecular structures determined. Crystals of trans-[PtPhCl(SEt2)2] (2) are triclinic (P1̄) with a = 10.112(6) Å, b = 13.158(2) Å, c = 14.714(5) Å, α = 102.48(2)°, β = 94.394(4)°, γ = 90.22(3)°, and Z = 4. Crystals of trans-[Pt(mesityl)Cl(SMe2)2] (4) are monoclinic (P21/c) with a = 13.158(2) Å, b = 9.170(1) Å, c = 16.013(3) Å, β = 120.93(2)°, and Z = 4, and crystals of [Pt(p-anisyl)Cl(SMe2)2] (5) are monoclinic (P21/n) with a = 9.879(4) Å, b = 8.128(2) Å, c = 19.460(5) Å, β = 96.56(3)°, and Z = 4. All complexes are square-planar, featuring Pt−Cl distances between 2.40 and 2.42 Å, indicating a large ground-state... (More)
Complexes trans-[PtRCl(SR‘2)2], where R = Ph, mesityl, and p-anisyl and R‘ = Me or Et, have been synthesized and their crystal and molecular structures determined. Crystals of trans-[PtPhCl(SEt2)2] (2) are triclinic (P1̄) with a = 10.112(6) Å, b = 13.158(2) Å, c = 14.714(5) Å, α = 102.48(2)°, β = 94.394(4)°, γ = 90.22(3)°, and Z = 4. Crystals of trans-[Pt(mesityl)Cl(SMe2)2] (4) are monoclinic (P21/c) with a = 13.158(2) Å, b = 9.170(1) Å, c = 16.013(3) Å, β = 120.93(2)°, and Z = 4, and crystals of [Pt(p-anisyl)Cl(SMe2)2] (5) are monoclinic (P21/n) with a = 9.879(4) Å, b = 8.128(2) Å, c = 19.460(5) Å, β = 96.56(3)°, and Z = 4. All complexes are square-planar, featuring Pt−Cl distances between 2.40 and 2.42 Å, indicating a large ground-state trans influence of the aryl group. The coordination geometry is maintained in methanol and chloroform solution as shown by 1H-NMR spectra. The kinetics of substitution of the labile chloride trans to aryl by various nucleophiles has been studied in methanol by variable-temperature and -pressure stopped-flow spectrophotometry. A two-term rate law with a well-developed solvolytic pathway is followed. Negative entropies and volumes of activation indicate an associative mode of activation in all cases, independent of steric blocking of the axial sites and a large Pt−Cl ground-state bond-weakening. Comparison of the reaction rates of the present series of complexes with their bis(phosphine) analogues and with related cyclometalated compounds shows that the triethylphosphine complexes are 2−3 orders of magnitude less reactive than the thioether complexes, which in turn are a factor 10−20 less reactive than the cyclometalated ones. This reactivity increase can be rationalized mainly in terms of a decrease in steric hindrance in the series. There seems to be no inherent differences with regard to trans labilizing ability of the aryl ligands in the various types of complexes, including the cyclometalated ones. (Less)
Abstract
Complexes trans-[PtRCl(SR‘2)2], where R = Ph, mesityl, and p-anisyl and R‘ = Me or Et, have been synthesized and their crystal and molecular structures determined. Crystals of trans-[PtPhCl(SEt2)2] (2) are triclinic (P1̄) with a = 10.112(6) Å, b = 13.158(2) Å, c = 14.714(5) Å, α = 102.48(2)°, β = 94.394(4)°, γ = 90.22(3)°, and Z = 4. Crystals of trans-[Pt(mesityl)Cl(SMe2)2] (4) are monoclinic (P21/c) with a = 13.158(2) Å, b = 9.170(1) Å, c = 16.013(3) Å, β = 120.93(2)°, and Z = 4, and crystals of [Pt(p-anisyl)Cl(SMe2)2] (5) are monoclinic (P21/n) with a = 9.879(4) Å, b = 8.128(2) Å, c = 19.460(5) Å, β = 96.56(3)°, and Z = 4. All complexes are square-planar, featuring Pt−Cl distances between 2.40 and 2.42 Å, indicating a large ground-state... (More)
Complexes trans-[PtRCl(SR‘2)2], where R = Ph, mesityl, and p-anisyl and R‘ = Me or Et, have been synthesized and their crystal and molecular structures determined. Crystals of trans-[PtPhCl(SEt2)2] (2) are triclinic (P1̄) with a = 10.112(6) Å, b = 13.158(2) Å, c = 14.714(5) Å, α = 102.48(2)°, β = 94.394(4)°, γ = 90.22(3)°, and Z = 4. Crystals of trans-[Pt(mesityl)Cl(SMe2)2] (4) are monoclinic (P21/c) with a = 13.158(2) Å, b = 9.170(1) Å, c = 16.013(3) Å, β = 120.93(2)°, and Z = 4, and crystals of [Pt(p-anisyl)Cl(SMe2)2] (5) are monoclinic (P21/n) with a = 9.879(4) Å, b = 8.128(2) Å, c = 19.460(5) Å, β = 96.56(3)°, and Z = 4. All complexes are square-planar, featuring Pt−Cl distances between 2.40 and 2.42 Å, indicating a large ground-state trans influence of the aryl group. The coordination geometry is maintained in methanol and chloroform solution as shown by 1H-NMR spectra. The kinetics of substitution of the labile chloride trans to aryl by various nucleophiles has been studied in methanol by variable-temperature and -pressure stopped-flow spectrophotometry. A two-term rate law with a well-developed solvolytic pathway is followed. Negative entropies and volumes of activation indicate an associative mode of activation in all cases, independent of steric blocking of the axial sites and a large Pt−Cl ground-state bond-weakening. Comparison of the reaction rates of the present series of complexes with their bis(phosphine) analogues and with related cyclometalated compounds shows that the triethylphosphine complexes are 2−3 orders of magnitude less reactive than the thioether complexes, which in turn are a factor 10−20 less reactive than the cyclometalated ones. This reactivity increase can be rationalized mainly in terms of a decrease in steric hindrance in the series. There seems to be no inherent differences with regard to trans labilizing ability of the aryl ligands in the various types of complexes, including the cyclometalated ones.
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organization
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type
Contribution to journal
publication status
published
subject
keywords
Platinum(II) complexes, Synthesis, XRD, X-ray diffraction, trans-influence, Ligand substitution, Kinetics, Reaction mechanism, Thioether complex, triethylphosphine complex, Cyclometalated complexes, Activation volumes, High-pressure stopped flow
in
Inorganic Chemistry
volume
1997
issue
36
pages
6 pages
publisher
The American Chemical Society
external identifiers
  • scopus:0000137478
ISSN
1520-510X
DOI
10.1021/ic970189o
language
English
LU publication?
yes
id
337058f3-d8e8-49a7-9b86-edc6e808d624
date added to LUP
2017-01-04 10:41:54
date last changed
2017-08-14 14:48:26
@article{337058f3-d8e8-49a7-9b86-edc6e808d624,
  abstract     = {Complexes trans-[PtRCl(SR‘2)2], where R = Ph, mesityl, and p-anisyl and R‘ = Me or Et, have been synthesized and their crystal and molecular structures determined. Crystals of trans-[PtPhCl(SEt2)2] (2) are triclinic (P1̄) with a = 10.112(6) Å, b = 13.158(2) Å, c = 14.714(5) Å, α = 102.48(2)°, β = 94.394(4)°, γ = 90.22(3)°, and Z = 4. Crystals of trans-[Pt(mesityl)Cl(SMe2)2] (4) are monoclinic (P21/c) with a = 13.158(2) Å, b = 9.170(1) Å, c = 16.013(3) Å, β = 120.93(2)°, and Z = 4, and crystals of [Pt(p-anisyl)Cl(SMe2)2] (5) are monoclinic (P21/n) with a = 9.879(4) Å, b = 8.128(2) Å, c = 19.460(5) Å, β = 96.56(3)°, and Z = 4. All complexes are square-planar, featuring Pt−Cl distances between 2.40 and 2.42 Å, indicating a large ground-state trans influence of the aryl group. The coordination geometry is maintained in methanol and chloroform solution as shown by 1H-NMR spectra. The kinetics of substitution of the labile chloride trans to aryl by various nucleophiles has been studied in methanol by variable-temperature and -pressure stopped-flow spectrophotometry. A two-term rate law with a well-developed solvolytic pathway is followed. Negative entropies and volumes of activation indicate an associative mode of activation in all cases, independent of steric blocking of the axial sites and a large Pt−Cl ground-state bond-weakening. Comparison of the reaction rates of the present series of complexes with their bis(phosphine) analogues and with related cyclometalated compounds shows that the triethylphosphine complexes are 2−3 orders of magnitude less reactive than the thioether complexes, which in turn are a factor 10−20 less reactive than the cyclometalated ones. This reactivity increase can be rationalized mainly in terms of a decrease in steric hindrance in the series. There seems to be no inherent differences with regard to trans labilizing ability of the aryl ligands in the various types of complexes, including the cyclometalated ones.<br/>},
  author       = {Wendt, Ola and Oskarsson, Åke and Leipoldt, Johann G. and Elding, Lars Ivar},
  issn         = {1520-510X},
  keyword      = {Platinum(II)  complexes,Synthesis,XRD,X-ray diffraction,trans-influence,Ligand substitution,Kinetics,Reaction mechanism,Thioether complex,triethylphosphine complex,Cyclometalated complexes,Activation volumes,High-pressure stopped flow},
  language     = {eng},
  month        = {09},
  number       = {36},
  pages        = {4514--4519},
  publisher    = {The American Chemical Society},
  series       = {Inorganic Chemistry},
  title        = {Synthesis, Structure, and Reactivity of Arylchlorobis(dialkyl sulfide)platinum(II) Complexes},
  url          = {http://dx.doi.org/10.1021/ic970189o},
  volume       = {1997},
  year         = {1997},
}