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Author(s): Carlos J. P. Monteiro
Sónia A. C. Carabineiro
Tobias Lauterbach
Christoph Hubbert
A. Stephen K. Hashmi
José L. Figueiredo
Mariette M. Pereira
Title: ( S )-BINOL Immobilized onto Multiwalled Carbon Nanotubes through Covalent Linkage: A New Approach for Hybrid Nanomaterials Characterization
Issue Date: 2015
Abstract: (S)-6-(4-(Methoxycarbonyl)phenyl)-1,1'-bis-2-naphthol,a chiral 1,1'-bis-2-naphthol (BINOL) derivative, was preparedvia Suzuki C¢C coupling and immobilized onto diamine-functionalized multiwalled carbon nanotubes. TheBINOL was first derivatized with a carboxylic acid, capable offorming an amide linkage with the amine-carbon nanotubemodified surface. The 4-methoxyphenylboronic acid was replacedby 3-fluoro-4-(methoxycarbonyl)phenylboronic acidand (S)-6-(3-fluoro-4-(methoxycarbonyl)phenyl)-1,1'-bis-2-naphthol was obtained and used as a probe to better quantifythe organic material. It was found that in the hybrid material,1/3 of amine groups have been transformed into thecorresponding amide (S)-BINOL derivative. The chemical andelectronic integrity of the chiral BINOL ligand is maintainedafter the ligand immobilization. Evaluation in diethyl zincand Ti(OiPr)4-catalyzed alkylation of benzaldehyde showedthat both methoxycarbonylphenyl and fluoromethoxycarbonylphenylBINOL moieties do not significantly influence thecatalytic activity or selectivity of the process. However, whenhybrid materials were used, similar activities were obtained,but with lower enantioselectivities. This result could be dueto a competitive alkylation reaction occurring on the carbonsurface or by the constraint caused by the ligand proximityon the support surface.
Subject: Química
Chemical sciences
Scientific areas: Ciências exactas e naturais::Química
Natural sciences::Chemical sciences
Related Information: info:eu-repo/grantAgreement/FCT - Fundação para a Ciência e Tecnologia/Projetos Estratégicos/UID/EQU/50020/2013- POCI-01-0145-FEDER-006984/Laboratório de Processos de Separação e Reação - Laboratório de Catálise e Materiais/LSRE-LCM
Document Type: Artigo em Revista Científica Internacional
Rights: restrictedAccess
Appears in Collections:FEUP - Artigo em Revista Científica Internacional

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