New, potentially chelating NHC ligands; synthesis, complexation studies, and preliminary catalytic evaluation

Arnold Ou, Linglin Wu, Alvaro Salvador, Gellert Sipos, Guangzhen Zhao, Brian W. Skelton, Alexandre N. Sobolev, Reto Dorta

Research output: Contribution to journalArticle

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Abstract

Two new N-heterocyclic carbene (NHC) ligands bearing 2-morpholino and 2-piperidinyl naphthyl wingtips were synthesised (2-SIMorNap and 2-SIPipNap). Nuclear magnetic resonance studies, in conjunction with crystal structures and derivatisation of the NHC salts using a chiral counteranion, revealed that the ligand wingtips are oriented anti with respect to each other. From the free carbene, palladium, ruthenium and iridium complexes were prepared. NHC-iridium dicarbonyl complexes were made in order to extract the TEP values for these ligands. The study showed that these NHC ligands are more electron-donating than normal, aryl-substituted NHCs. The palladium complexes were tested in representative Suzuki-Miyaura cross-coupling reactions and compared to the state of the art systems. Ruthenium-catalysed ring-closing metathesis with these ligands was also performed. It was found that Grubbs’ 2nd generation catalyst incorporating 2-SIPipNap did not initiate at room temperature and required heating for RCM to occur.

Original languageEnglish
Pages (from-to)3631-3641
Number of pages11
JournalDalton Transactions
Volume46
Issue number11
DOIs
Publication statusPublished - 21 Mar 2017

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Chelation
Complexation
Ligands
Iridium
Ruthenium
Palladium
Bearings (structural)
Morpholinos
Salts
Crystal structure
Nuclear magnetic resonance
carbene
Heating
Catalysts
Electrons
Temperature

Cite this

Ou, Arnold ; Wu, Linglin ; Salvador, Alvaro ; Sipos, Gellert ; Zhao, Guangzhen ; Skelton, Brian W. ; Sobolev, Alexandre N. ; Dorta, Reto. / New, potentially chelating NHC ligands; synthesis, complexation studies, and preliminary catalytic evaluation. In: Dalton Transactions. 2017 ; Vol. 46, No. 11. pp. 3631-3641.
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New, potentially chelating NHC ligands; synthesis, complexation studies, and preliminary catalytic evaluation. / Ou, Arnold; Wu, Linglin; Salvador, Alvaro; Sipos, Gellert; Zhao, Guangzhen; Skelton, Brian W.; Sobolev, Alexandre N.; Dorta, Reto.

In: Dalton Transactions, Vol. 46, No. 11, 21.03.2017, p. 3631-3641.

Research output: Contribution to journalArticle

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AU - Ou, Arnold

AU - Wu, Linglin

AU - Salvador, Alvaro

AU - Sipos, Gellert

AU - Zhao, Guangzhen

AU - Skelton, Brian W.

AU - Sobolev, Alexandre N.

AU - Dorta, Reto

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