title: New, potentially chelating NHC ligands; synthesis, complexation studies, and preliminary catalytic evaluation.
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' 2ndgeneration catalyst incorporating 2-SIPipNap did not initiate at room temperature and required heating for RCM to occur.
authors.affiliation: School of Chemistry and Biochemistry, University of Western Australia, 35 Stirling Highway, Perth 6009, Western Australia, Australia. reto.dorta@uwa.edu.au.
authors.forename: Arnold
authors.initials: A
authors.lastname: Ou
authors.affiliation: School of Chemistry and Biochemistry, University of Western Australia, 35 Stirling Highway, Perth 6009, Western Australia, Australia. reto.dorta@uwa.edu.au.
authors.forename: Linglin
authors.initials: L
authors.lastname: Wu
authors.affiliation: School of Chemistry and Biochemistry, University of Western Australia, 35 Stirling Highway, Perth 6009, Western Australia, Australia. reto.dorta@uwa.edu.au.
authors.forename: Alvaro
authors.initials: A
authors.lastname: Salvador
authors.affiliation: School of Chemistry and Biochemistry, University of Western Australia, 35 Stirling Highway, Perth 6009, Western Australia, Australia. reto.dorta@uwa.edu.au.
authors.forename: Gellert
authors.identifier: http://orcid.org/0000-0001-6956-9009
authors.initials: G
authors.lastname: Sipos
authors.affiliation: School of Chemistry and Biochemistry, University of Western Australia, 35 Stirling Highway, Perth 6009, Western Australia, Australia. reto.dorta@uwa.edu.au.
authors.forename: Guangzhen
authors.initials: G
authors.lastname: Zhao
authors.affiliation: Centre for Microscopy, Characterisation and Analysis, University of Western Australia, 35 Stirling Highway, Perth 6009, Western Australia, Australia.
authors.forename: Brian W
authors.initials: BW
authors.lastname: Skelton
authors.affiliation: Centre for Microscopy, Characterisation and Analysis, University of Western Australia, 35 Stirling Highway, Perth 6009, Western Australia, Australia.
authors.forename: Alexandre N
authors.initials: AN
authors.lastname: Sobolev
authors.affiliation: School of Chemistry and Biochemistry, University of Western Australia, 35 Stirling Highway, Perth 6009, Western Australia, Australia. reto.dorta@uwa.edu.au.
authors.forename: Reto
authors.identifier: http://orcid.org/0000-0003-1240-2755
authors.initials: R
authors.lastname: Dorta