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dc.contributor.authorLi, Shenyu
dc.contributor.authorKee, Choonwee
dc.contributor.authorHuang, Kuo-Wei
dc.contributor.authorHor, Andy Sum Andy
dc.contributor.authorZhao, Jin
dc.date.accessioned2015-08-02T09:12:06Z
dc.date.available2015-08-02T09:12:06Z
dc.date.issued2010-04-26
dc.identifier.issn02767333
dc.identifier.doi10.1021/om900980a
dc.identifier.urihttp://hdl.handle.net/10754/561467
dc.description.abstractA series of N-heterocyclic carbene (NHC) complexes CpMo(CO) 2(NHC)X (NHC = IMe = 1,3-dimethylimidazol-2-ylidene, X = Br, 1; NHC = 1,3-dipropylimidazol-2-ylidene, X = Br, 2; NHC = IMes = 1,3-bis(2,4,6- trimethylphenyl)imidazol-2-ylidene, X = Br, 3; NHC = IBz = 1,3-dibenzylimidazol- 2-ylidene, X = Br, 4a, and X = Cl, 4b; NHC = 1-methyl-3-propylimidazol-2- ylidene, X = Br, 5) and [CpMo(CO)2(IMes)(CH3CN)][BF 4] (6) have been synthesized and fully characterized. The stability of metal-NHC ligand bonds in these compounds under oxidative conditions has been investigated. The thermally stable Mo(VI) dioxo NHC complex [CpMoO 2(IMes)][BF4] (9) has been isolated by the oxidation of the ionic complex 6 by TBHP (tert-butyl hydrogen peroxide). Complex 6 can be applied as a very active (TOFs up to 3400 h-1) and selective olefin epoxidation catalyst. While under oxidative conditions (in the presence of TBHP), compounds 1-5 decompose into imidazolium bromide and imidazolium polyoxomolybdate. The formation of polyoxomolybdate as oxidation products had not been observed in a similar epoxidation catalyzed by Mo(II) and Mo(VI) complexes. DFT studies suggest that the presence of Br- destabilizes the CpMo(VI) oxo NHC carbene species, consistent with the experimental observations. © 2010 American Chemical Society.
dc.description.sponsorshipWe are grateful to the Ministry of Education (MOE) of Singapore Academic Research Fund (AcRF) Tier 1 Grant (WBS No. R-143-000-373-112). S.Y. L. also thanks National University of Singapore for the scholarship. K.W.H. acknowledges the support from KAUST baseline funding. We thank Ms. Geok Kheng Tan and Dr. Lip Lin Koh for determining the X-ray crystal structures.
dc.publisherAmerican Chemical Society (ACS)
dc.titleCyclopentadienyl molybdenum(II/VI) N-heterocyclic carbene complexes: Synthesis, structure, and reactivity under oxidative conditions
dc.typeArticle
dc.contributor.departmentBiological and Environmental Sciences and Engineering (BESE) Division
dc.contributor.departmentChemical Science Program
dc.contributor.departmentHomogeneous Catalysis Laboratory (HCL)
dc.contributor.departmentKAUST Catalysis Center (KCC)
dc.contributor.departmentPhysical Science and Engineering (PSE) Division
dc.identifier.journalOrganometallics
dc.contributor.institutionDepartment of Chemistry, National University of Singapore, 3 Science Drive 3, 117543 Singapore, Singapore
dc.contributor.institutionGerman Institute of Science and Technology-TUM Asia Pte. Ltd., Pixel Building, 10 Central Exchange Green, #03-01, 138649, Singapore, Singapore
kaust.personHuang, Kuo-Wei
dc.relation.issupplementedbyDOI:10.5517/cct457b
dc.relation.issupplementedbyDOI:10.5517/cct458c
dc.relation.issupplementedbyDOI:10.5517/cct459d
dc.relation.issupplementedbyDOI:10.5517/cct45bf
dc.relation.issupplementedbyDOI:10.5517/cct45cg
dc.relation.issupplementedbyDOI:10.5517/ccw6jq9
display.relations<b> Is Supplemented By:</b> <br/> <ul><li><i>[Dataset]</i> <br/> Li, S., Kee, C. W., Huang, K.-W., Hor, T. S. A., & Zhao, J. (2011). CCDC 748781: Experimental Crystal Structure Determination [Data set]. Cambridge Crystallographic Data Centre. https://doi.org/10.5517/cct457b. DOI: <a href="https://doi.org/10.5517/cct457b">10.5517/cct457b</a> HANDLE: <a href="http://hdl.handle.net/10754/624609">10754/624609</a></li><li><i>[Dataset]</i> <br/> Li, S., Kee, C. W., Huang, K.-W., Hor, T. S. A., & Zhao, J. (2011). CCDC 748782: Experimental Crystal Structure Determination [Data set]. Cambridge Crystallographic Data Centre. https://doi.org/10.5517/cct458c. DOI: <a href="https://doi.org/10.5517/cct458c">10.5517/cct458c</a> HANDLE: <a href="http://hdl.handle.net/10754/624610">10754/624610</a></li><li><i>[Dataset]</i> <br/> Li, S., Kee, C. W., Huang, K.-W., Hor, T. S. A., & Zhao, J. (2011). CCDC 748783: Experimental Crystal Structure Determination [Data set]. Cambridge Crystallographic Data Centre. https://doi.org/10.5517/cct459d. DOI: <a href="https://doi.org/10.5517/cct459d">10.5517/cct459d</a> HANDLE: <a href="http://hdl.handle.net/10754/624611">10754/624611</a></li><li><i>[Dataset]</i> <br/> Li, S., Kee, C. W., Huang, K.-W., Hor, T. S. A., & Zhao, J. (2011). CCDC 748784: Experimental Crystal Structure Determination [Data set]. Cambridge Crystallographic Data Centre. https://doi.org/10.5517/cct45bf. DOI: <a href="https://doi.org/10.5517/cct45bf">10.5517/cct45bf</a> HANDLE: <a href="http://hdl.handle.net/10754/624612">10754/624612</a></li><li><i>[Dataset]</i> <br/> Li, S., Kee, C. W., Huang, K.-W., Hor, T. S. A., & Zhao, J. (2011). CCDC 748785: Experimental Crystal Structure Determination [Data set]. Cambridge Crystallographic Data Centre. https://doi.org/10.5517/cct45cg. DOI: <a href="https://doi.org/10.5517/cct45cg">10.5517/cct45cg</a> HANDLE: <a href="http://hdl.handle.net/10754/624613">10754/624613</a></li><li><i>[Dataset]</i> <br/> Li, S., Kee, C. W., Huang, K.-W., Hor, T. S. A., & Zhao, J. (2011). CCDC 810641: Experimental Crystal Structure Determination [Data set]. Cambridge Crystallographic Data Centre. https://doi.org/10.5517/ccw6jq9. DOI: <a href="https://doi.org/10.5517/ccw6jq9">10.5517/ccw6jq9</a> HANDLE: <a href="http://hdl.handle.net/10754/624632">10754/624632</a></li></ul>


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