One-N, six-membered heterocyclic carbene complexes and the remote heteroatom concept

Simple item page
dc.contributor.authorRaubenheimer H.G.
dc.contributor.authorCronje S.
dc.date.accessioned2011-05-15T15:59:06Z
dc.date.available2011-05-15T15:59:06Z
dc.date.issued2008
dc.description.abstractA whole library of six-membered N-heterocyclic carbene complexes of Ni(ii) and Pd(ii) were prepared by oxidative substitution. In some of these compounds the heteroatom occurs in a position distant from the carbene donor atom. Combined structural and physical data, especially 13C NMR results, indicate carbene character in such ligands. DFT quantum mechanical calculation at the RI-BP56/SVP level allowed the extraction of valuable chemical information predicting that rNHC (r = remote) ligands would bond more strongly than their nNHC (n = normal) isomers. This result is also corroborated by calculations on the metal complexes themselves. Orbital overlap (mainly σ) follows the order N2HC5 < nN1HC6 < rN 1HC6 when ligands derived from halo-imidazolium and halo-pyridinium salts are compared. In C-C coupling catalysis using Pd(ii) and Ni(ii) complexes, the simple one-N, six-membered carbene complexes are superior to simple two-N, five-membered examples but clear differentiation between nNHC and rNHC precatalysts in the former family, is not always possible. © The Royal Society of Chemistry.
dc.description.versionArticle
dc.identifier.citationDalton Transactions
dc.identifier.citation10
dc.identifier.issn14779226
dc.identifier.other10.1039/b715592a
dc.identifier.urihttp://hdl.handle.net/10019.1/11002
dc.subjectCatalysis
dc.subjectIsomers
dc.subjectLigands
dc.subjectNuclear magnetic resonance
dc.subjectOxidation
dc.subjectQuantum theory
dc.subjectSubstitution reactions
dc.subjectChemical information
dc.subjectDifferentiation
dc.subjectHeteroatoms
dc.subjectPhysical data
dc.subjectPrecatalysts
dc.subjectCarbon inorganic compounds
dc.titleOne-N, six-membered heterocyclic carbene complexes and the remote heteroatom concept
dc.typeArticle
Files
Collections
Stellenbosch University - Scopus Publications