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Synthesis, structure, and reactivity of arylfluoro platinum(II) complexes.

Nilsson, Patrik LU ; Plamper, Felix and Wendt, Ola LU (2003) In Organometallics 22(25). p.5235-5242
Abstract
Complexes of the type trans-[PtPhFL2], where L = PPh3 (4), PMe2Ph (5), were synthesized. Complex 4 was characterized by X-ray crystallography. The equilibrium constant for the substitution of the fluoride trans to phenyl in 4 by Cl- and I- was determined, and the stability sequence follows the normal trend seen in "soft" metal centers: i.e., the Pt has a preference for the halide in the order I > Cl > F; the difference is, however, fairly small. The substitution kinetics follow the usual two-term rate law, and the rate constants for the solvolytic (k1) and the direct (k2) reaction pathways were determined to be k1 = (9.7 ± 2.4) × 10-5 s-1, k2 = (11.7 ± 0.3) × 10-2 M-1 s-1 and k1 = (7.1 ± 4.9) × 10-5 s-1, k2 = (23.0 ± 1.3) × 10-2 M-1... (More)
Complexes of the type trans-[PtPhFL2], where L = PPh3 (4), PMe2Ph (5), were synthesized. Complex 4 was characterized by X-ray crystallography. The equilibrium constant for the substitution of the fluoride trans to phenyl in 4 by Cl- and I- was determined, and the stability sequence follows the normal trend seen in "soft" metal centers: i.e., the Pt has a preference for the halide in the order I > Cl > F; the difference is, however, fairly small. The substitution kinetics follow the usual two-term rate law, and the rate constants for the solvolytic (k1) and the direct (k2) reaction pathways were determined to be k1 = (9.7 ± 2.4) × 10-5 s-1, k2 = (11.7 ± 0.3) × 10-2 M-1 s-1 and k1 = (7.1 ± 4.9) × 10-5 s-1, k2 = (23.0 ± 1.3) × 10-2 M-1 s-1 for Cl- and I-, respectively. Activation parameters for the solvolytic and direct pathways with Cl- as incoming ligand are typical for associative processes and were determined to be H = 77.8 ± 5.5 kJ mol-1, S = -56 ± 18 J K-1mol-1 and H = 67.6 ± 1.8 kJ mol-1, S = -37 ± 6 J K-1mol-1, respectively. Complexes 4 and 5 react with Me3SnPh, and within 2-15 min there is a complete conversion to products. 4 gives a single product, trans-[PtPhMe(PPh3)2], which was characterized by X-ray crystallography. 5 gives two products: trans-[PtPhMe(PMe2Ph)2] and trans-[PtPh2(PMe2Ph)2]. Steric effects on the reactivity speak in favor of an associative mechanism. The surprisingly high reactivity for the transmetalations, compared to the substitution reactions, can be explained in terms of an associative mechanism, where a strong, bridging Sn-F interaction stabilizes the transition state. Furthermore, only trans products are formed; i.e., we have an exclusive F-for-R (R = Me, Ph) substitution at these platinum fluoro complexes. Treatment of 4 with phenylacetylene in benzene at room temperature gives the alkynyl complex trans-[PtPh(CCPh)(PPh3)2] (8). (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Organometallics
volume
22
issue
25
pages
5235 - 5242
publisher
The American Chemical Society
external identifiers
  • wos:000186977200011
  • scopus:0346148368
ISSN
1520-6041
DOI
10.1021/om030524i
language
English
LU publication?
yes
id
035aad2c-e10e-4713-ae50-71647fefecb2 (old id 128370)
date added to LUP
2007-07-09 14:04:43
date last changed
2018-01-07 05:13:55
@article{035aad2c-e10e-4713-ae50-71647fefecb2,
  abstract     = {Complexes of the type trans-[PtPhFL2], where L = PPh3 (4), PMe2Ph (5), were synthesized. Complex 4 was characterized by X-ray crystallography. The equilibrium constant for the substitution of the fluoride trans to phenyl in 4 by Cl- and I- was determined, and the stability sequence follows the normal trend seen in "soft" metal centers: i.e., the Pt has a preference for the halide in the order I > Cl > F; the difference is, however, fairly small. The substitution kinetics follow the usual two-term rate law, and the rate constants for the solvolytic (k1) and the direct (k2) reaction pathways were determined to be k1 = (9.7 ± 2.4) × 10-5 s-1, k2 = (11.7 ± 0.3) × 10-2 M-1 s-1 and k1 = (7.1 ± 4.9) × 10-5 s-1, k2 = (23.0 ± 1.3) × 10-2 M-1 s-1 for Cl- and I-, respectively. Activation parameters for the solvolytic and direct pathways with Cl- as incoming ligand are typical for associative processes and were determined to be H = 77.8 ± 5.5 kJ mol-1, S = -56 ± 18 J K-1mol-1 and H = 67.6 ± 1.8 kJ mol-1, S = -37 ± 6 J K-1mol-1, respectively. Complexes 4 and 5 react with Me3SnPh, and within 2-15 min there is a complete conversion to products. 4 gives a single product, trans-[PtPhMe(PPh3)2], which was characterized by X-ray crystallography. 5 gives two products: trans-[PtPhMe(PMe2Ph)2] and trans-[PtPh2(PMe2Ph)2]. Steric effects on the reactivity speak in favor of an associative mechanism. The surprisingly high reactivity for the transmetalations, compared to the substitution reactions, can be explained in terms of an associative mechanism, where a strong, bridging Sn-F interaction stabilizes the transition state. Furthermore, only trans products are formed; i.e., we have an exclusive F-for-R (R = Me, Ph) substitution at these platinum fluoro complexes. Treatment of 4 with phenylacetylene in benzene at room temperature gives the alkynyl complex trans-[PtPh(CCPh)(PPh3)2] (8).},
  author       = {Nilsson, Patrik and Plamper, Felix and Wendt, Ola},
  issn         = {1520-6041},
  language     = {eng},
  number       = {25},
  pages        = {5235--5242},
  publisher    = {The American Chemical Society},
  series       = {Organometallics},
  title        = {Synthesis, structure, and reactivity of arylfluoro platinum(II) complexes.},
  url          = {http://dx.doi.org/10.1021/om030524i},
  volume       = {22},
  year         = {2003},
}