An Oligosilsesquioxane Cage Functionalized with Molybdenum(II) Organometallic Fragments

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dc.contributor.authorDias Filho, Newton L. [UNESP]
dc.contributor.authorPortugal, Fatima C. M.
dc.contributor.authorNogueira, J. M. F.
dc.contributor.authorBrandao, Paula
dc.contributor.authorFelix, Vitor
dc.contributor.authorVaz, Pedro D.
dc.contributor.authorNunes, Carla D.
dc.contributor.authorVeiros, Luis F.
dc.contributor.authorVilla de Brito, Maria J.
dc.contributor.authorCalhorda, Maria Jose
dc.contributor.institutionUniv Lisbon
dc.contributor.institutionUniversidade Estadual Paulista (Unesp)
dc.contributor.institutionUniv Aveiro
dc.contributor.institutionUniv Tecn Lisboa
dc.date.accessioned2014-05-20T13:29:50Z
dc.date.available2014-05-20T13:29:50Z
dc.date.issued2012-06-25
dc.description.abstractA silsesquioxane cage polymer functionalized with eight chloropropyl arms (1, T-8-PrCl) reacted with 2,2'-dipyridiylamine (DPA) to afford a new derivative with eight pendant linear chains (2, T-8-Pr-DPA). Further reaction with [Mo(eta(3)-C3H5)Br(CO)(2)(NCMe)(2)] afforded another derivative containing three molybdenum units (3, T-8-Pr-DPA-Mo), after substitution of the two nitrite ligands in each complex. These are the first silsesquioxane species containing DPA and the Mo(eta(3)-C3H5)Br(CO)(2) fragment. The three materials were characterized by H-1, C-13, Si-29, and Mo-95 NMR, FTIR, XRD, and elemental analysis, and T-8-PrCl (1) was also structurally characterized by single-crystal X-ray diffraction. It was identified as a low-temperature polymorph of this material. Elemental analysis indicated that all Cl atoms in the parent material T-8-PrCl (1) were substituted by the deprotonated DPA group in T-8-Pr-DPA (2). However, only three [Mo(eta(3)-C3H5)Br(CO)(2)(DPA)] units were detected in T-8-Pr-DPA-Mo (3). A comprehensive NMR study, complemented with DFT calculations, was carried out in order to detect the effect of Mo coordination on the cage silicon and on the protons and carbons of the propyl chain, but no significant effects were observed. Both H-1 and Si-29 chemical shifts vary upon introducing DPA but remain the same after reaction with the Mo(II) precursor. The Mo-95 NMR data reveal that the metal is not sensitive to the cage. The catalytic activity of 3 was tested as a precursor in the epoxidation of cyclooctene and styrene in the presence of TBHP. Despite the high selectivity toward the epoxides, the conversion and turnover frequencies were low, reflecting the behavior of the [Mo(eta(3)-C3H5)Br(CO),(DPA)] complex.en
dc.description.affiliationUniv Lisbon, Fac Ciencias, Dept Quim & Bioquim, P-1749016 Lisbon, Portugal
dc.description.affiliationUNESP Univ Estadual Paulista, Fac Engn Ilha Solteira, Dept Quim & Fis, BR-15385000 Ilha Solteira, SP, Brazil
dc.description.affiliationUniv Lisbon, Fac Ciencias, Ctr Quim & Bioquim, P-1749016 Lisbon, Portugal
dc.description.affiliationUniv Aveiro, CICECO, Dept Quim, P-3810193 Aveiro, Portugal
dc.description.affiliationUniv Aveiro, Seccao Autonoma Ciencias Saude, P-3810193 Aveiro, Portugal
dc.description.affiliationUniv Tecn Lisboa, Inst Super Tecn, Ctr Quim Estrutural, P-1049001 Lisbon, Portugal
dc.description.affiliationUnespUNESP Univ Estadual Paulista, Fac Engn Ilha Solteira, Dept Quim & Fis, BR-15385000 Ilha Solteira, SP, Brazil
dc.description.sponsorshipFCT
dc.description.sponsorshipFundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
dc.description.sponsorshipUNESP
dc.description.sponsorshipCoordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
dc.description.sponsorshipIdFCT: SFRH/BD/24598/2005
dc.description.sponsorshipIdFCT: PTDC/QUI-QUI/099389/2008
dc.description.sponsorshipIdFCT: PEst-OE/QUI/UI0100/2011
dc.description.sponsorshipIdFCT: PEst-OE/QUI/UI0612/2011
dc.format.extent4495-4503
dc.identifierhttp://dx.doi.org/10.1021/om3003043
dc.identifier.citationOrganometallics. Washington: Amer Chemical Soc, v. 31, n. 12, p. 4495-4503, 2012.
dc.identifier.doi10.1021/om3003043
dc.identifier.issn0276-7333
dc.identifier.urihttp://hdl.handle.net/11449/10107
dc.identifier.wosWOS:000305588000015
dc.language.isoeng
dc.publisherAmer Chemical Soc
dc.relation.ispartofOrganometallics
dc.relation.ispartofjcr4.051
dc.relation.ispartofsjr1,652
dc.rights.accessRightsAcesso restrito
dc.sourceWeb of Science
dc.titleAn Oligosilsesquioxane Cage Functionalized with Molybdenum(II) Organometallic Fragmentsen
dc.typeArtigo
dcterms.licensehttp://pubs.acs.org/page/copyright/index.html
dcterms.rightsHolderAmer Chemical Soc
unesp.campusUniversidade Estadual Paulista (Unesp), Faculdade de Engenharia, Ilha Solteirapt

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Artigos - Física e Química - FEIS