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DFT Investigation of the Mechanism of Phosphine-Thioether Isomerization in the Triosmium Cluster Os-3(CO)(10)(Ph2PCH2CH2SMe): Migratory Preference for the Formation of an Edge-Bridged Thioether versus a Phosphine Moiety

Hrovat, David A.; Nordlander, Ebbe LU and Richmond, Michael G. (2012) In Organometallics 31(18). p.6608-6613
Abstract
The rearrangement of the phosphine-thioether ligand in 1,2-(P-eq,S-eq)-Os-3(CO)(10)(Ph2PCH2CH2SMe) to 1,1-(P-eq,S-ax)-Os-3(CO)(10)(Ph2PCH2CH2SMe) was investigated by electronic structure calculations. The chelated isomer lies 2.5 kcal/mol lower in energy than its bridged counterpart, and the barrier computed for the mechanism is in agreement with the results from our earlier experimental study. Phosphine-thioether isomerization occurs via three distinct steps that involve the migration of the CO and SMe groups in a plane that is perpendicular to the trimetallic core. One of the intermediates on the reaction surface corresponds to the 50e cluster Os-3(CO)(9)(mu-CO)(mu-Ph2PCH2CH2SMe), whose edge-bridging thioether moiety functions as a 4e... (More)
The rearrangement of the phosphine-thioether ligand in 1,2-(P-eq,S-eq)-Os-3(CO)(10)(Ph2PCH2CH2SMe) to 1,1-(P-eq,S-ax)-Os-3(CO)(10)(Ph2PCH2CH2SMe) was investigated by electronic structure calculations. The chelated isomer lies 2.5 kcal/mol lower in energy than its bridged counterpart, and the barrier computed for the mechanism is in agreement with the results from our earlier experimental study. Phosphine-thioether isomerization occurs via three distinct steps that involve the migration of the CO and SMe groups in a plane that is perpendicular to the trimetallic core. One of the intermediates on the reaction surface corresponds to the 50e cluster Os-3(CO)(9)(mu-CO)(mu-Ph2PCH2CH2SMe), whose edge-bridging thioether moiety functions as a 4e donor ligand. Alternative mechanisms involving ligand dissociation/association and merry-go-round sequences are energetically prohibitive. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Organometallics
volume
31
issue
18
pages
6608 - 6613
publisher
The American Chemical Society
external identifiers
  • wos:000309022700014
  • scopus:84866718355
ISSN
1520-6041
DOI
10.1021/om300640t
language
English
LU publication?
yes
id
b050b522-c420-46a4-8bd0-aa7135dc016b (old id 3187564)
date added to LUP
2012-12-06 12:14:11
date last changed
2017-10-22 03:06:27
@article{b050b522-c420-46a4-8bd0-aa7135dc016b,
  abstract     = {The rearrangement of the phosphine-thioether ligand in 1,2-(P-eq,S-eq)-Os-3(CO)(10)(Ph2PCH2CH2SMe) to 1,1-(P-eq,S-ax)-Os-3(CO)(10)(Ph2PCH2CH2SMe) was investigated by electronic structure calculations. The chelated isomer lies 2.5 kcal/mol lower in energy than its bridged counterpart, and the barrier computed for the mechanism is in agreement with the results from our earlier experimental study. Phosphine-thioether isomerization occurs via three distinct steps that involve the migration of the CO and SMe groups in a plane that is perpendicular to the trimetallic core. One of the intermediates on the reaction surface corresponds to the 50e cluster Os-3(CO)(9)(mu-CO)(mu-Ph2PCH2CH2SMe), whose edge-bridging thioether moiety functions as a 4e donor ligand. Alternative mechanisms involving ligand dissociation/association and merry-go-round sequences are energetically prohibitive.},
  author       = {Hrovat, David A. and Nordlander, Ebbe and Richmond, Michael G.},
  issn         = {1520-6041},
  language     = {eng},
  number       = {18},
  pages        = {6608--6613},
  publisher    = {The American Chemical Society},
  series       = {Organometallics},
  title        = {DFT Investigation of the Mechanism of Phosphine-Thioether Isomerization in the Triosmium Cluster Os-3(CO)(10)(Ph2PCH2CH2SMe): Migratory Preference for the Formation of an Edge-Bridged Thioether versus a Phosphine Moiety},
  url          = {http://dx.doi.org/10.1021/om300640t},
  volume       = {31},
  year         = {2012},
}