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Theoretical studies of the oxidative addition of azolium salts to a model Wilkinson's catalyst


Hawkes, KJ and McGuinness, DS and Cavell, KJ and Yates, BF, Theoretical studies of the oxidative addition of azolium salts to a model Wilkinson's catalyst, Dalton Transactions, (16) pp. 2505-2513. ISSN 1477-9226 (2004) [Refereed Article]

DOI: doi:10.1039/b407088g


The oxidative addition of 1,3-dimethylimidazolium to a model Wilkinson's catalyst (RhCl(PH3)3) has been studied with density functional calculations (B3LYP). According to our free energy calculations, the octahedral rhodium carbene hydride product forms from initial predissociation of a phosphine molecule to subsequently form a 5 ligand intermediate; however, results indicate that a six ligand, associative route with a concerted three-centred transition structure may also be competitive. Exchange of the phosphine molecule on the metal centre with trimethylphosphine had a significant effect in lowering the barrier to oxidative addition and decreasing the endothermicity of the reaction. Solvation was found to have a moderate effect on the overall reaction. Bulk solvent calculations reflected a relative stabilisation of reactants for both pathways, resulting in an endothermic overall reaction. A study of alternative azolium salts revealed the saturated 1,3-dimethy1-4,5-dihydroimidazolium resulted in little change to the reaction geometries or energies, while the use of 3-methylthiazolium salt significantly reduced the barrier to addition and increased the exothermicity of the reaction considerably.

Item Details

Item Type:Refereed Article
Research Division:Chemical Sciences
Research Group:Inorganic chemistry
Research Field:Organometallic chemistry
Objective Division:Expanding Knowledge
Objective Group:Expanding knowledge
Objective Field:Expanding knowledge in the chemical sciences
UTAS Author:Hawkes, KJ (Dr Kirsty Hawkes)
UTAS Author:McGuinness, DS (Dr David McGuinness)
UTAS Author:Cavell, KJ (Professor Kingsley Cavell)
UTAS Author:Yates, BF (Professor Brian Yates)
ID Code:31986
Year Published:2004
Web of Science® Times Cited:21
Deposited By:Chemistry
Deposited On:2004-08-01
Last Modified:2011-09-30

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