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Article: Chiral copper-bipyridine complexes: Synthesis, characterization and mechanistic studies on asymmetric cyclopropanation

TitleChiral copper-bipyridine complexes: Synthesis, characterization and mechanistic studies on asymmetric cyclopropanation
Authors
KeywordsAsymmetric catalysis
Chiral bipyridines
Copper-bipyridine complexes
Cyclopropanation
Issue Date2011
PublisherElsevier BV. The Journal's web site is located at http://www.elsevier.com/locate/poly
Citation
Polyhedron, 2011, v. 30 n. 1, p. 178-186 How to Cite?
AbstractChiral bipyridine ligands of different steric properties when reacted with CuCl 2 formed orange, yellow or green solids of new copper(II) complexes, [Cu(L)Cl 2] (L = L2-6), in good yield. Together with [Cu(L1)Cl 2], these complexes were characterized in solution by UV-Vis spectroscopy and cyclic voltammetry. The complexes give d-d transitions between 860 and 970 nm, and exhibit one quasi-reversible Cu(II)/Cu(I) couple between +0.405 V and +0.516 V versus NHE. Two of the copper(II) complexes, [Cu(L5)Cl 2] and [Cu(L6)Cl 2], and a copper(I) complex of L1, [Cu(L1)Cl], were characterized by X-ray crystallography. The triflate derivatives of both the Cu(I) and Cu(II) complexes are active catalysts towards the cyclopropanation of ethyl diazoacetate with styrene. The asymmetric induction suffers when the size difference between the alkyl and alkoxyl groups was minimized. The mechanism of the cyclopropanation was studied with kinetic and competition experiments. The rate is first order in catalyst and ethyl diazoacetate, inverse order with styrene and is strongly affected by the counterion. © 2010 Elsevier Ltd. All rights reserved.
Persistent Identifierhttp://hdl.handle.net/10722/139006
ISSN
2015 Impact Factor: 2.108
2015 SCImago Journal Rankings: 0.592
ISI Accession Number ID
Funding AgencyGrant Number
Hong Kong Research Grants Council GRFCityU 101108
Area of Excellence Scheme established under the University Grants Committee of the Hong Kong SAR, ChinaAoE/P-10/01
City University of Hong Kong
Funding Information:

Financial support from the Hong Kong Research Grants Council GRF (CityU 101108) and the Area of Excellence Scheme established under the University Grants Committee of the Hong Kong SAR, China (Project No. AoE/P-10/01) and the City University of Hong Kong are gratefully acknowledged.

References
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DC FieldValueLanguage
dc.contributor.authorLee, WSen_HK
dc.contributor.authorYeung, CTen_HK
dc.contributor.authorSham, KCen_HK
dc.contributor.authorWong, WTen_HK
dc.contributor.authorKwong, HLen_HK
dc.date.accessioned2011-09-23T05:44:02Z-
dc.date.available2011-09-23T05:44:02Z-
dc.date.issued2011en_HK
dc.identifier.citationPolyhedron, 2011, v. 30 n. 1, p. 178-186en_HK
dc.identifier.issn0277-5387en_HK
dc.identifier.urihttp://hdl.handle.net/10722/139006-
dc.description.abstractChiral bipyridine ligands of different steric properties when reacted with CuCl 2 formed orange, yellow or green solids of new copper(II) complexes, [Cu(L)Cl 2] (L = L2-6), in good yield. Together with [Cu(L1)Cl 2], these complexes were characterized in solution by UV-Vis spectroscopy and cyclic voltammetry. The complexes give d-d transitions between 860 and 970 nm, and exhibit one quasi-reversible Cu(II)/Cu(I) couple between +0.405 V and +0.516 V versus NHE. Two of the copper(II) complexes, [Cu(L5)Cl 2] and [Cu(L6)Cl 2], and a copper(I) complex of L1, [Cu(L1)Cl], were characterized by X-ray crystallography. The triflate derivatives of both the Cu(I) and Cu(II) complexes are active catalysts towards the cyclopropanation of ethyl diazoacetate with styrene. The asymmetric induction suffers when the size difference between the alkyl and alkoxyl groups was minimized. The mechanism of the cyclopropanation was studied with kinetic and competition experiments. The rate is first order in catalyst and ethyl diazoacetate, inverse order with styrene and is strongly affected by the counterion. © 2010 Elsevier Ltd. All rights reserved.en_HK
dc.languageengen_US
dc.publisherElsevier BV. The Journal's web site is located at http://www.elsevier.com/locate/polyen_HK
dc.relation.ispartofPolyhedronen_HK
dc.rightsNOTICE: this is the author’s version of a work that was accepted for publication in <Journal title>. Changes resulting from the publishing process, such as peer review, editing, corrections, structural formatting, and other quality control mechanisms may not be reflected in this document. Changes may have been made to this work since it was submitted for publication. A definitive version was subsequently published in PUBLICATION, [VOL#, ISSUE#, (DATE)] DOI#-
dc.subjectAsymmetric catalysisen_HK
dc.subjectChiral bipyridinesen_HK
dc.subjectCopper-bipyridine complexesen_HK
dc.subjectCyclopropanationen_HK
dc.titleChiral copper-bipyridine complexes: Synthesis, characterization and mechanistic studies on asymmetric cyclopropanationen_HK
dc.typeArticleen_HK
dc.identifier.emailWong, WT: wtwong@hku.hken_HK
dc.identifier.authorityWong, WT=rp00811en_HK
dc.description.naturelink_to_subscribed_fulltext-
dc.identifier.doi10.1016/j.poly.2010.10.021en_HK
dc.identifier.scopuseid_2-s2.0-78650847079en_HK
dc.identifier.hkuros195815en_US
dc.relation.referenceshttp://www.scopus.com/mlt/select.url?eid=2-s2.0-78650847079&selection=ref&src=s&origin=recordpageen_HK
dc.identifier.volume30en_HK
dc.identifier.issue1en_HK
dc.identifier.spage178en_HK
dc.identifier.epage186en_HK
dc.identifier.isiWOS:000287059400024-
dc.publisher.placeNetherlandsen_HK
dc.relation.projectInstitute of molecular technology for drug discovery and synthesis-
dc.identifier.scopusauthoridLee, WS=7407089119en_HK
dc.identifier.scopusauthoridYeung, CT=7201354137en_HK
dc.identifier.scopusauthoridSham, KC=24538178700en_HK
dc.identifier.scopusauthoridWong, WT=7403973084en_HK
dc.identifier.scopusauthoridKwong, HL=35569416300en_HK
dc.identifier.citeulike8230305-

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