Further studies of the Enhanced Structural Carborane Effect: Tricarbonylruthenium and related derivatives of benzocarborane, dihydrobenzocarborane and biphenylcarborane

Samuel Powley, Georgina Margaret Rosair, Alan Jeffrey Welch

Research output: Contribution to journalArticle

Abstract

Detailed comparison of the molecular structures of [1,2-μ-(C4H4)-3,3,3-(CO)3-3,1,2-closo-RuC2B9H9] (1) and [1,2-μ-(C4H6)-3,3,3-(CO)3-3,1,2-closo-RuC2B9H9] (2) reveals evidence for an Enhanced Structural Carborane Effect in 1 arising from the involvement of the cage pπ orbitals in the exopolyhedral ring to some degree. A minor co-product in the synthesis of 2 is [η-{1,2-μ-(C4H6)}-3,3-(CO)2-3,1,2-closo-RuC2B9H9] (3). Compounds 2 and 3 are readily interconverted, since heating 2 to reflux in THF or reaction with Me3NO affords 3 which readily reacts with CO to regenerate 2. The η-ene bonding in 3 is also displaced by PMe3, P(OMe)3 and t-BuNC to yield [1,2-μ-(C4H6)-3,3-(CO)2-3-PMe3-3,1,2-closo-RuC2B9H9] (4), [1,2-μ-(C4H6)-3,3-(CO)2-3-P(OMe)3-3,1,2-closo-RuC2B9H9] (5) and [1,2-μ-(C4H6)-3,3-(CO)2-3-t-BuNC-3,1,2-closo-RuC2B9H9] (6), respectively. Structural studies of 4–6, focussing on the Exopolyhedral Ligand Orientation of the {Ru(CO)2L} fragment relative to the C2B3 carborane face, are discussed in terms of the structural trans effects of PMe3, P(OMe)3 and t-BuNC relative to that of CO. An improved synthesis of [1,2-μ-(C6H4)2-1,2-closo-C2B10H10], “biphenylcarborane”, is reported following which the first transition-metal derivatives of this species, [1,2-μ-(C6H4)2-3-Cp-3,1,2-closo-CoC2B9H9] (7) and [1,2-μ-(C6H4)2-3,3,3-(CO)3-3,1,2-closo-RuC2B9H9] (8), are prepared. Comparisons of the structures of 7 and 8 with the corresponding benzocarborane derivatives [1,2-μ-(C4H4)-3-Cp-3,1,2-closo-CoC2B9H9] and 1, respectively, suggest that Clar's rule for aromaticity can be applied to polycyclic aromatic hydrocarbons fused onto carborane cages.
Original languageEnglish
Pages (from-to)11742-11752
Number of pages11
JournalDalton Transactions
Volume45
Issue number29
Early online date7 Jun 2016
DOIs
Publication statusPublished - 7 Aug 2016

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Carbon Monoxide
Derivatives
Polycyclic Aromatic Hydrocarbons
Molecular structure
Transition metals
Ligands
Heating

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@article{8f08fd5d48ca4e1ea3847bac56f345ef,
title = "Further studies of the Enhanced Structural Carborane Effect: Tricarbonylruthenium and related derivatives of benzocarborane, dihydrobenzocarborane and biphenylcarborane",
abstract = "Detailed comparison of the molecular structures of [1,2-μ-(C4H4)-3,3,3-(CO)3-3,1,2-closo-RuC2B9H9] (1) and [1,2-μ-(C4H6)-3,3,3-(CO)3-3,1,2-closo-RuC2B9H9] (2) reveals evidence for an Enhanced Structural Carborane Effect in 1 arising from the involvement of the cage pπ orbitals in the exopolyhedral ring to some degree. A minor co-product in the synthesis of 2 is [η-{1,2-μ-(C4H6)}-3,3-(CO)2-3,1,2-closo-RuC2B9H9] (3). Compounds 2 and 3 are readily interconverted, since heating 2 to reflux in THF or reaction with Me3NO affords 3 which readily reacts with CO to regenerate 2. The η-ene bonding in 3 is also displaced by PMe3, P(OMe)3 and t-BuNC to yield [1,2-μ-(C4H6)-3,3-(CO)2-3-PMe3-3,1,2-closo-RuC2B9H9] (4), [1,2-μ-(C4H6)-3,3-(CO)2-3-P(OMe)3-3,1,2-closo-RuC2B9H9] (5) and [1,2-μ-(C4H6)-3,3-(CO)2-3-t-BuNC-3,1,2-closo-RuC2B9H9] (6), respectively. Structural studies of 4–6, focussing on the Exopolyhedral Ligand Orientation of the {Ru(CO)2L} fragment relative to the C2B3 carborane face, are discussed in terms of the structural trans effects of PMe3, P(OMe)3 and t-BuNC relative to that of CO. An improved synthesis of [1,2-μ-(C6H4)2-1,2-closo-C2B10H10], “biphenylcarborane”, is reported following which the first transition-metal derivatives of this species, [1,2-μ-(C6H4)2-3-Cp-3,1,2-closo-CoC2B9H9] (7) and [1,2-μ-(C6H4)2-3,3,3-(CO)3-3,1,2-closo-RuC2B9H9] (8), are prepared. Comparisons of the structures of 7 and 8 with the corresponding benzocarborane derivatives [1,2-μ-(C4H4)-3-Cp-3,1,2-closo-CoC2B9H9] and 1, respectively, suggest that Clar's rule for aromaticity can be applied to polycyclic aromatic hydrocarbons fused onto carborane cages.",
author = "Samuel Powley and Rosair, {Georgina Margaret} and Welch, {Alan Jeffrey}",
year = "2016",
month = "8",
day = "7",
doi = "10.1039/C6DT01888B",
language = "English",
volume = "45",
pages = "11742--11752",
journal = "Dalton Transactions",
issn = "1477-9226",
publisher = "Royal Society of Chemistry",
number = "29",

}

Further studies of the Enhanced Structural Carborane Effect: Tricarbonylruthenium and related derivatives of benzocarborane, dihydrobenzocarborane and biphenylcarborane. / Powley, Samuel; Rosair, Georgina Margaret; Welch, Alan Jeffrey.

In: Dalton Transactions, Vol. 45, No. 29, 07.08.2016, p. 11742-11752.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Further studies of the Enhanced Structural Carborane Effect: Tricarbonylruthenium and related derivatives of benzocarborane, dihydrobenzocarborane and biphenylcarborane

AU - Powley, Samuel

AU - Rosair, Georgina Margaret

AU - Welch, Alan Jeffrey

PY - 2016/8/7

Y1 - 2016/8/7

N2 - Detailed comparison of the molecular structures of [1,2-μ-(C4H4)-3,3,3-(CO)3-3,1,2-closo-RuC2B9H9] (1) and [1,2-μ-(C4H6)-3,3,3-(CO)3-3,1,2-closo-RuC2B9H9] (2) reveals evidence for an Enhanced Structural Carborane Effect in 1 arising from the involvement of the cage pπ orbitals in the exopolyhedral ring to some degree. A minor co-product in the synthesis of 2 is [η-{1,2-μ-(C4H6)}-3,3-(CO)2-3,1,2-closo-RuC2B9H9] (3). Compounds 2 and 3 are readily interconverted, since heating 2 to reflux in THF or reaction with Me3NO affords 3 which readily reacts with CO to regenerate 2. The η-ene bonding in 3 is also displaced by PMe3, P(OMe)3 and t-BuNC to yield [1,2-μ-(C4H6)-3,3-(CO)2-3-PMe3-3,1,2-closo-RuC2B9H9] (4), [1,2-μ-(C4H6)-3,3-(CO)2-3-P(OMe)3-3,1,2-closo-RuC2B9H9] (5) and [1,2-μ-(C4H6)-3,3-(CO)2-3-t-BuNC-3,1,2-closo-RuC2B9H9] (6), respectively. Structural studies of 4–6, focussing on the Exopolyhedral Ligand Orientation of the {Ru(CO)2L} fragment relative to the C2B3 carborane face, are discussed in terms of the structural trans effects of PMe3, P(OMe)3 and t-BuNC relative to that of CO. An improved synthesis of [1,2-μ-(C6H4)2-1,2-closo-C2B10H10], “biphenylcarborane”, is reported following which the first transition-metal derivatives of this species, [1,2-μ-(C6H4)2-3-Cp-3,1,2-closo-CoC2B9H9] (7) and [1,2-μ-(C6H4)2-3,3,3-(CO)3-3,1,2-closo-RuC2B9H9] (8), are prepared. Comparisons of the structures of 7 and 8 with the corresponding benzocarborane derivatives [1,2-μ-(C4H4)-3-Cp-3,1,2-closo-CoC2B9H9] and 1, respectively, suggest that Clar's rule for aromaticity can be applied to polycyclic aromatic hydrocarbons fused onto carborane cages.

AB - Detailed comparison of the molecular structures of [1,2-μ-(C4H4)-3,3,3-(CO)3-3,1,2-closo-RuC2B9H9] (1) and [1,2-μ-(C4H6)-3,3,3-(CO)3-3,1,2-closo-RuC2B9H9] (2) reveals evidence for an Enhanced Structural Carborane Effect in 1 arising from the involvement of the cage pπ orbitals in the exopolyhedral ring to some degree. A minor co-product in the synthesis of 2 is [η-{1,2-μ-(C4H6)}-3,3-(CO)2-3,1,2-closo-RuC2B9H9] (3). Compounds 2 and 3 are readily interconverted, since heating 2 to reflux in THF or reaction with Me3NO affords 3 which readily reacts with CO to regenerate 2. The η-ene bonding in 3 is also displaced by PMe3, P(OMe)3 and t-BuNC to yield [1,2-μ-(C4H6)-3,3-(CO)2-3-PMe3-3,1,2-closo-RuC2B9H9] (4), [1,2-μ-(C4H6)-3,3-(CO)2-3-P(OMe)3-3,1,2-closo-RuC2B9H9] (5) and [1,2-μ-(C4H6)-3,3-(CO)2-3-t-BuNC-3,1,2-closo-RuC2B9H9] (6), respectively. Structural studies of 4–6, focussing on the Exopolyhedral Ligand Orientation of the {Ru(CO)2L} fragment relative to the C2B3 carborane face, are discussed in terms of the structural trans effects of PMe3, P(OMe)3 and t-BuNC relative to that of CO. An improved synthesis of [1,2-μ-(C6H4)2-1,2-closo-C2B10H10], “biphenylcarborane”, is reported following which the first transition-metal derivatives of this species, [1,2-μ-(C6H4)2-3-Cp-3,1,2-closo-CoC2B9H9] (7) and [1,2-μ-(C6H4)2-3,3,3-(CO)3-3,1,2-closo-RuC2B9H9] (8), are prepared. Comparisons of the structures of 7 and 8 with the corresponding benzocarborane derivatives [1,2-μ-(C4H4)-3-Cp-3,1,2-closo-CoC2B9H9] and 1, respectively, suggest that Clar's rule for aromaticity can be applied to polycyclic aromatic hydrocarbons fused onto carborane cages.

U2 - 10.1039/C6DT01888B

DO - 10.1039/C6DT01888B

M3 - Article

VL - 45

SP - 11742

EP - 11752

JO - Dalton Transactions

JF - Dalton Transactions

SN - 1477-9226

IS - 29

ER -