Experimental and Computational Studies of the Isomerization Reactions of Bidentate Phosphine Ligands in Triosmium Clusters: Kinetics of the Rearrangements from Bridged to Chelated Isomers and X-ray Structures of the Clusters Os3 (CO)10 (dppbz), 1,1-Os3 (CO)10 (dppbzF4), HOs3 (CO)9 [μ -1,2-PhP (C6H4-ɳ1) C6H4PPh2], and HOs3 (CO)9- [μ-1,2-PhP (C6H4-ɳ 1) C6F4PPh2]

PDF Version Also Available for Download.

Description

Article on experimental and computational studies of the isomerization reactions of bidentate phosphine ligands in triosmium clusters.

Creation Information

Zhang, Xue; Kandala, Srikanth; Yang, Li; Watson, William H.; Wang, Xiaoping; Hrovat, David A. et al. February 22, 2011.

Context

This article is part of the collection entitled: UNT Scholarly Works and was provided by UNT College of Arts and Sciences to Digital Library, a digital repository hosted by the UNT Libraries. It has been viewed 537 times , with 7 in the last month . More information about this article can be viewed below.

Who

People and organizations associated with either the creation of this article or its content.

Authors

Publisher

Provided By

UNT College of Arts and Sciences

The UNT College of Arts and Sciences educates students in traditional liberal arts, performing arts, sciences, professional, and technical academic programs. In addition to its departments, the college includes academic centers, institutes, programs, and offices providing diverse courses of study.

Contact Us

What

Descriptive information to help identify this article. Follow the links below to find similar items on the Digital Library.

Degree Information

Description

Article on experimental and computational studies of the isomerization reactions of bidentate phosphine ligands in triosmium clusters.

Notes

Reprinted with permission from the Organometallics. Copyright 2011 American Chemical Society.

Abstract: The diphosphine ligand 1,2-bis(diphenylphosphino) benzene (dppbz) reacts with the activated cluster 1,2-Os3 (CO)10 (MeCN)2 (1) at room temperature to furnish a mixture of the triosmium clusters 1,2-Os3 (CO)10 (dppbz) (2) and 1,1-Os3 (CO)10 (dppbz) (3), along with a trace amount of the hydride cluster HOs3 (CO)9 [μ -1,2-PhP (C6H4-ɳ1) C6H4PPh2] (4). The dppbz-bridged cluster 2 forms as the kinetically controlled product and irreversibly transforms to the corresponding chelated isomer 3 at ambient temperature. The disposition of the dppbz ligand in 2 and 3 has been established by X-ray crystallography and 31P NMR spectroscopy, and the kinetics for the conversion 2 → 3 have been followed by UV-vis spectroscopy in toluene over the temperature range 318-343 K. The calculated activation parameters (ΔH‡ = 21.6(3)kcal/mol; ΔS‡ = -11(1)eu) and lack of CO inhibition support an intramolecular isomerization mechanism that involves the simultaneous migration of phosphine and CO groups about the cluster polyhedron. The reaction between 1 and the fluorinated diphosphine ligand 1,2-bis(diphenylphosphino) tetrafluorobenzene (dppbzF4) was examined under similar reaction conditions and was found to afford the chelated cluster 1,1-Os3 (CO)10 (dppbzF4) (6) as the sole observable product. The absence of the expected bridged isomer 1,2-Os3 (CO)10 (dppbzF4) (5) suggests that the dppbzF4 ligand destabilizes 5, thus accounting for the rapid isomerization of 5 to 6. Near-UV irradiation of clusters 3 and 6 leads to CO loss and ortho metalation of an ancillary aryl group. The resulting hydride clusters 4 and HOs3 (CO)9 [µ-1,2-PhP(C6H4-ɳ1) C6F4PPh2] (7) have been isolated and fully characterized by spectroscopic and X-ray diffraction analyses. Both 4 and 7 react with added CO under mild conditions to regenerate 3 and 6, respectively, in quantitative yield. The rearrangements of bridged to chelated diphosphine complexes in this genre of decacarbonyl clusters have been investigated by DFT calculations. The computational results support a concerted process, involving the scrambling of equatorial CO and phosphine groups via a classical merry-go-round exchange scheme. The barriers computed for this mechanism agree well with those that have been measured, and steric compression within the bridged diphosphine groups of the reactants has been calculated to reduce the barrier heights for the rearrangement.

Source

  • Organometallics, 2011, Washington DC: American Chemical Society, pp. 1253-1268

Language

Item Type

Identifier

Unique identifying numbers for this article in the Digital Library or other systems.

Publication Information

  • Publication Title: Organometallics
  • Volume: 30
  • Page Start: 1253
  • Page End: 1268
  • Pages: 16
  • Peer Reviewed: Yes

Collections

This article is part of the following collection of related materials.

UNT Scholarly Works

Materials from the UNT community's research, creative, and scholarly activities and UNT's Open Access Repository. Access to some items in this collection may be restricted.

What responsibilities do I have when using this article?

When

Dates and time periods associated with this article.

Creation Date

  • February 22, 2011

Added to The UNT Digital Library

  • Jan. 31, 2012, 10:30 a.m.

Description Last Updated

  • Aug. 30, 2017, 3:10 p.m.

Usage Statistics

When was this article last used?

Yesterday: 0
Past 30 days: 7
Total Uses: 537

Interact With This Article

Here are some suggestions for what to do next.

Start Reading

PDF Version Also Available for Download.

Citations, Rights, Re-Use

Zhang, Xue; Kandala, Srikanth; Yang, Li; Watson, William H.; Wang, Xiaoping; Hrovat, David A. et al. Experimental and Computational Studies of the Isomerization Reactions of Bidentate Phosphine Ligands in Triosmium Clusters: Kinetics of the Rearrangements from Bridged to Chelated Isomers and X-ray Structures of the Clusters Os3 (CO)10 (dppbz), 1,1-Os3 (CO)10 (dppbzF4), HOs3 (CO)9 [μ -1,2-PhP (C6H4-ɳ1) C6H4PPh2], and HOs3 (CO)9- [μ-1,2-PhP (C6H4-ɳ 1) C6F4PPh2], article, February 22, 2011; [Washington, DC]. (digital.library.unt.edu/ark:/67531/metadc71815/: accessed October 18, 2017), University of North Texas Libraries, Digital Library, digital.library.unt.edu; crediting UNT College of Arts and Sciences.