The conformations of 13-vertex ML2C2B10 metallacarboranes: experimental and computational studies

Kelly J. Dalby, David Ellis, Stefan Erhardt, Ruaraidh D McIntosh, Stuart A. Macgregor, Karen Rae, Georgina M. Rosair, Volker Settels, Alan J. Welch, Bruce E. Hodson, Thomas D. McGrath, F. Gordon A. Stone

Research output: Contribution to journalArticle

Abstract

The docosahedral metallacarboranes 4,4-(PMe2Ph) 2-4,1,6-closo-PtC2B10H12, 4,4-(PMe2Ph)2-4,1,10-closo-PtC2B 10H12, and [N(PPh3)2][4,4-cod-4,1, 10-closo-RhC2B10H12] were prepared by reduction/ metalation of either 1,2-closo-C2B10H 12 or 1,12-closo-C2B10H12. All three species were fully characterized, with a particular point of interest of the latter being the conformation of the {ML2} fragment relative to the carborane ligand face. Comparison with conformations previously established for six other ML2C2B10 species of varying heteroatom patterns (4,1,2-MC2B10, 4,1,6-/WC2Bi0, 4,1,10-MC2B10, and 4,1,12-MC2B10) reveals clear preferences. In all cases a qualitative understanding of these was afforded by simple MO arguments applied to the model heteroarene complexes [(PH3)2PtC2B4H6] 2- and [(PH3)2PtCB5H 6]3-. Moreover, DFT calculations on [(PH3) 2PtC2B4H6]2 in its various isomeric forms approximately reproduced the observed conformations in the 4,1,2-, 4,1,6-, and 4,1,10-MC2B10 species, although analogous calculations on [(PH3)2PtCB5H 6]3- did not reproduce the conformation observed in the 4,1,12-MC2B10 metallacarborane. DFT calculations on (PH3)2PtC2B10H12 yielded good agreement with experimental conformations in all four isomeric cases. Apparent discrepancies between observed and computed Pt-C distances were probed by further refinement of the 4,1,2- model to 1,2-(CH2) 3-4,4-(PMe3)2-4,1,2-closo-PtC2B 10H10. This still has a more distorted structure than measured experimentally for 1,2-(CH2)3-4,4-(PMe 2Ph)2-4,1,2-closo-PtC2B10H 10, but the structural differences lie on a very shallow potential energy surface. For the model compound a henicosahedral transition state was located 8.3 kcal mol-1 above the ground-state structure, consistent with the fluxionality of 1,2-(CH2)3-4,4-(PMe 2Ph)2-4,1,2-closo-PtC2B10H 10 in solution. © 2007 American Chemical Society.

Original languageEnglish
Pages (from-to)3302-3314
Number of pages13
JournalJournal of the American Chemical Society
Volume129
Issue number11
DOIs
Publication statusPublished - 21 Mar 2007

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Dalby, Kelly J. ; Ellis, David ; Erhardt, Stefan ; McIntosh, Ruaraidh D ; Macgregor, Stuart A. ; Rae, Karen ; Rosair, Georgina M. ; Settels, Volker ; Welch, Alan J. ; Hodson, Bruce E. ; McGrath, Thomas D. ; Stone, F. Gordon A. / The conformations of 13-vertex ML2C2B10 metallacarboranes : experimental and computational studies. In: Journal of the American Chemical Society. 2007 ; Vol. 129, No. 11. pp. 3302-3314.
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title = "The conformations of 13-vertex ML2C2B10 metallacarboranes: experimental and computational studies",
abstract = "The docosahedral metallacarboranes 4,4-(PMe2Ph) 2-4,1,6-closo-PtC2B10H12, 4,4-(PMe2Ph)2-4,1,10-closo-PtC2B 10H12, and [N(PPh3)2][4,4-cod-4,1, 10-closo-RhC2B10H12] were prepared by reduction/ metalation of either 1,2-closo-C2B10H 12 or 1,12-closo-C2B10H12. All three species were fully characterized, with a particular point of interest of the latter being the conformation of the {ML2} fragment relative to the carborane ligand face. Comparison with conformations previously established for six other ML2C2B10 species of varying heteroatom patterns (4,1,2-MC2B10, 4,1,6-/WC2Bi0, 4,1,10-MC2B10, and 4,1,12-MC2B10) reveals clear preferences. In all cases a qualitative understanding of these was afforded by simple MO arguments applied to the model heteroarene complexes [(PH3)2PtC2B4H6] 2- and [(PH3)2PtCB5H 6]3-. Moreover, DFT calculations on [(PH3) 2PtC2B4H6]2 in its various isomeric forms approximately reproduced the observed conformations in the 4,1,2-, 4,1,6-, and 4,1,10-MC2B10 species, although analogous calculations on [(PH3)2PtCB5H 6]3- did not reproduce the conformation observed in the 4,1,12-MC2B10 metallacarborane. DFT calculations on (PH3)2PtC2B10H12 yielded good agreement with experimental conformations in all four isomeric cases. Apparent discrepancies between observed and computed Pt-C distances were probed by further refinement of the 4,1,2- model to 1,2-(CH2) 3-4,4-(PMe3)2-4,1,2-closo-PtC2B 10H10. This still has a more distorted structure than measured experimentally for 1,2-(CH2)3-4,4-(PMe 2Ph)2-4,1,2-closo-PtC2B10H 10, but the structural differences lie on a very shallow potential energy surface. For the model compound a henicosahedral transition state was located 8.3 kcal mol-1 above the ground-state structure, consistent with the fluxionality of 1,2-(CH2)3-4,4-(PMe 2Ph)2-4,1,2-closo-PtC2B10H 10 in solution. {\circledC} 2007 American Chemical Society.",
author = "Dalby, {Kelly J.} and David Ellis and Stefan Erhardt and McIntosh, {Ruaraidh D} and Macgregor, {Stuart A.} and Karen Rae and Rosair, {Georgina M.} and Volker Settels and Welch, {Alan J.} and Hodson, {Bruce E.} and McGrath, {Thomas D.} and Stone, {F. Gordon A.}",
year = "2007",
month = "3",
day = "21",
doi = "10.1021/ja067698m",
language = "English",
volume = "129",
pages = "3302--3314",
journal = "Journal of the American Chemical Society",
issn = "0002-7863",
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Dalby, KJ, Ellis, D, Erhardt, S, McIntosh, RD, Macgregor, SA, Rae, K, Rosair, GM, Settels, V, Welch, AJ, Hodson, BE, McGrath, TD & Stone, FGA 2007, 'The conformations of 13-vertex ML2C2B10 metallacarboranes: experimental and computational studies', Journal of the American Chemical Society, vol. 129, no. 11, pp. 3302-3314. https://doi.org/10.1021/ja067698m

The conformations of 13-vertex ML2C2B10 metallacarboranes : experimental and computational studies. / Dalby, Kelly J.; Ellis, David; Erhardt, Stefan; McIntosh, Ruaraidh D; Macgregor, Stuart A.; Rae, Karen; Rosair, Georgina M.; Settels, Volker; Welch, Alan J.; Hodson, Bruce E.; McGrath, Thomas D.; Stone, F. Gordon A.

In: Journal of the American Chemical Society, Vol. 129, No. 11, 21.03.2007, p. 3302-3314.

Research output: Contribution to journalArticle

TY - JOUR

T1 - The conformations of 13-vertex ML2C2B10 metallacarboranes

T2 - experimental and computational studies

AU - Dalby, Kelly J.

AU - Ellis, David

AU - Erhardt, Stefan

AU - McIntosh, Ruaraidh D

AU - Macgregor, Stuart A.

AU - Rae, Karen

AU - Rosair, Georgina M.

AU - Settels, Volker

AU - Welch, Alan J.

AU - Hodson, Bruce E.

AU - McGrath, Thomas D.

AU - Stone, F. Gordon A.

PY - 2007/3/21

Y1 - 2007/3/21

N2 - The docosahedral metallacarboranes 4,4-(PMe2Ph) 2-4,1,6-closo-PtC2B10H12, 4,4-(PMe2Ph)2-4,1,10-closo-PtC2B 10H12, and [N(PPh3)2][4,4-cod-4,1, 10-closo-RhC2B10H12] were prepared by reduction/ metalation of either 1,2-closo-C2B10H 12 or 1,12-closo-C2B10H12. All three species were fully characterized, with a particular point of interest of the latter being the conformation of the {ML2} fragment relative to the carborane ligand face. Comparison with conformations previously established for six other ML2C2B10 species of varying heteroatom patterns (4,1,2-MC2B10, 4,1,6-/WC2Bi0, 4,1,10-MC2B10, and 4,1,12-MC2B10) reveals clear preferences. In all cases a qualitative understanding of these was afforded by simple MO arguments applied to the model heteroarene complexes [(PH3)2PtC2B4H6] 2- and [(PH3)2PtCB5H 6]3-. Moreover, DFT calculations on [(PH3) 2PtC2B4H6]2 in its various isomeric forms approximately reproduced the observed conformations in the 4,1,2-, 4,1,6-, and 4,1,10-MC2B10 species, although analogous calculations on [(PH3)2PtCB5H 6]3- did not reproduce the conformation observed in the 4,1,12-MC2B10 metallacarborane. DFT calculations on (PH3)2PtC2B10H12 yielded good agreement with experimental conformations in all four isomeric cases. Apparent discrepancies between observed and computed Pt-C distances were probed by further refinement of the 4,1,2- model to 1,2-(CH2) 3-4,4-(PMe3)2-4,1,2-closo-PtC2B 10H10. This still has a more distorted structure than measured experimentally for 1,2-(CH2)3-4,4-(PMe 2Ph)2-4,1,2-closo-PtC2B10H 10, but the structural differences lie on a very shallow potential energy surface. For the model compound a henicosahedral transition state was located 8.3 kcal mol-1 above the ground-state structure, consistent with the fluxionality of 1,2-(CH2)3-4,4-(PMe 2Ph)2-4,1,2-closo-PtC2B10H 10 in solution. © 2007 American Chemical Society.

AB - The docosahedral metallacarboranes 4,4-(PMe2Ph) 2-4,1,6-closo-PtC2B10H12, 4,4-(PMe2Ph)2-4,1,10-closo-PtC2B 10H12, and [N(PPh3)2][4,4-cod-4,1, 10-closo-RhC2B10H12] were prepared by reduction/ metalation of either 1,2-closo-C2B10H 12 or 1,12-closo-C2B10H12. All three species were fully characterized, with a particular point of interest of the latter being the conformation of the {ML2} fragment relative to the carborane ligand face. Comparison with conformations previously established for six other ML2C2B10 species of varying heteroatom patterns (4,1,2-MC2B10, 4,1,6-/WC2Bi0, 4,1,10-MC2B10, and 4,1,12-MC2B10) reveals clear preferences. In all cases a qualitative understanding of these was afforded by simple MO arguments applied to the model heteroarene complexes [(PH3)2PtC2B4H6] 2- and [(PH3)2PtCB5H 6]3-. Moreover, DFT calculations on [(PH3) 2PtC2B4H6]2 in its various isomeric forms approximately reproduced the observed conformations in the 4,1,2-, 4,1,6-, and 4,1,10-MC2B10 species, although analogous calculations on [(PH3)2PtCB5H 6]3- did not reproduce the conformation observed in the 4,1,12-MC2B10 metallacarborane. DFT calculations on (PH3)2PtC2B10H12 yielded good agreement with experimental conformations in all four isomeric cases. Apparent discrepancies between observed and computed Pt-C distances were probed by further refinement of the 4,1,2- model to 1,2-(CH2) 3-4,4-(PMe3)2-4,1,2-closo-PtC2B 10H10. This still has a more distorted structure than measured experimentally for 1,2-(CH2)3-4,4-(PMe 2Ph)2-4,1,2-closo-PtC2B10H 10, but the structural differences lie on a very shallow potential energy surface. For the model compound a henicosahedral transition state was located 8.3 kcal mol-1 above the ground-state structure, consistent with the fluxionality of 1,2-(CH2)3-4,4-(PMe 2Ph)2-4,1,2-closo-PtC2B10H 10 in solution. © 2007 American Chemical Society.

U2 - 10.1021/ja067698m

DO - 10.1021/ja067698m

M3 - Article

C2 - 17315872

VL - 129

SP - 3302

EP - 3314

JO - Journal of the American Chemical Society

JF - Journal of the American Chemical Society

SN - 0002-7863

IS - 11

ER -