Cooperative effect by monopodal silica-supported niobium com-plexes pairs enhancing catalytic cyclic carbonate production

Handle URI:
http://hdl.handle.net/10754/552780
Title:
Cooperative effect by monopodal silica-supported niobium com-plexes pairs enhancing catalytic cyclic carbonate production
Authors:
D'Elia, Valerio; Dong, Hailin; Rossini, Aaron J; Widdifield, Cory M.; Vummaleti, Sai V. C.; Minenkov, Yury; Poater, Albert; Abou-Hamad, Edy; Pelletier, Jeremie D. A.; Cavallo, Luigi ( 0000-0002-1398-338X ) ; Emsley, Lyndon; Basset, Jean-Marie ( 0000-0003-3166-8882 )
Abstract:
Recent discoveries highlighted the activity and the intriguing mechanistic features of NbCl5 as a molecular catalyst for the cycloaddition of CO2 and epoxides under ambient conditions. This has inspired the preparation of novel silica supported Nb-species by reacting a molecular niobium precursor [NbCl5•OEt2] with silica dehydroxylated at 700 °C (SiO2-700) or at 200 oC (SiO2-200) to generate diverse surface complexes. The product of the reaction between SiO2-700 and [NbCl5•OEt2] was identified as a monopodal supported surface species [≡SiONbCl4•OEt2] (1a). The reactions of SiO2-200 with the niobium precursor, according to two different protocols, generated surface complexes 2a and 3a presenting significant, but different, populations of the monopodal surface complex along with bipodal [(≡SiO)2NbCl3•OEt2]. 93Nb SSNMR spectra of 1a-3a and 31P SSNMR on their PMe3 derivatives (1b-3b) led to the unambiguous assignment of 1a as a single site, monopodal Nb-species while 2a and 3a were found to present two distinct surface-supported components, with 2a being mostly monopodal [≡SiONbCl4•OEt2] and 3a being mostly bipodal [≡S ONbCl3•OEt2]. Double-quantum/single-quantum 31P NMR correlation experiment carried out on 2b supported the existence of vicinal Nb centers on the silica surface for this species. 1a-3a were active heterogeneous catalysts for the synthesis of propylene carbonate from CO2 and propylene oxide under mild catalytic conditions; the performance of 2a was found to significantly surpass that of 1a and 3a. With the support of a systematic DFT study carried out on model silica surfaces, the observed differences in catalytic efficiency were correlated with an unprece-dented cooperative effect between two neighboring Nb centers on the surface of 2a. This is in an excellent agreement with our previous discoveries regarding the mechanism of the NbCl5 catalyzed cycloaddition in the homogeneous phase.
KAUST Department:
KAUST Catalysis Center (KCC)
Citation:
Cooperative effect by monopodal silica-supported niobium com-plexes pairs enhancing catalytic cyclic carbonate production 2015:150507190632009 Journal of the American Chemical Society
Publisher:
American Chemical Society (ACS)
Journal:
Journal of the American Chemical Society
Issue Date:
7-May-2015
DOI:
10.1021/jacs.5b02872
Type:
Article
ISSN:
0002-7863; 1520-5126
Additional Links:
http://pubs.acs.org/doi/abs/10.1021/jacs.5b02872
Appears in Collections:
Articles; KAUST Catalysis Center (KCC)

Full metadata record

DC FieldValue Language
dc.contributor.authorD'Elia, Valerioen
dc.contributor.authorDong, Hailinen
dc.contributor.authorRossini, Aaron Jen
dc.contributor.authorWiddifield, Cory M.en
dc.contributor.authorVummaleti, Sai V. C.en
dc.contributor.authorMinenkov, Yuryen
dc.contributor.authorPoater, Alberten
dc.contributor.authorAbou-Hamad, Edyen
dc.contributor.authorPelletier, Jeremie D. A.en
dc.contributor.authorCavallo, Luigien
dc.contributor.authorEmsley, Lyndonen
dc.contributor.authorBasset, Jean-Marieen
dc.date.accessioned2015-05-14T07:08:15Zen
dc.date.available2015-05-14T07:08:15Zen
dc.date.issued2015-05-07en
dc.identifier.citationCooperative effect by monopodal silica-supported niobium com-plexes pairs enhancing catalytic cyclic carbonate production 2015:150507190632009 Journal of the American Chemical Societyen
dc.identifier.issn0002-7863en
dc.identifier.issn1520-5126en
dc.identifier.doi10.1021/jacs.5b02872en
dc.identifier.urihttp://hdl.handle.net/10754/552780en
dc.description.abstractRecent discoveries highlighted the activity and the intriguing mechanistic features of NbCl5 as a molecular catalyst for the cycloaddition of CO2 and epoxides under ambient conditions. This has inspired the preparation of novel silica supported Nb-species by reacting a molecular niobium precursor [NbCl5•OEt2] with silica dehydroxylated at 700 °C (SiO2-700) or at 200 oC (SiO2-200) to generate diverse surface complexes. The product of the reaction between SiO2-700 and [NbCl5•OEt2] was identified as a monopodal supported surface species [≡SiONbCl4•OEt2] (1a). The reactions of SiO2-200 with the niobium precursor, according to two different protocols, generated surface complexes 2a and 3a presenting significant, but different, populations of the monopodal surface complex along with bipodal [(≡SiO)2NbCl3•OEt2]. 93Nb SSNMR spectra of 1a-3a and 31P SSNMR on their PMe3 derivatives (1b-3b) led to the unambiguous assignment of 1a as a single site, monopodal Nb-species while 2a and 3a were found to present two distinct surface-supported components, with 2a being mostly monopodal [≡SiONbCl4•OEt2] and 3a being mostly bipodal [≡S ONbCl3•OEt2]. Double-quantum/single-quantum 31P NMR correlation experiment carried out on 2b supported the existence of vicinal Nb centers on the silica surface for this species. 1a-3a were active heterogeneous catalysts for the synthesis of propylene carbonate from CO2 and propylene oxide under mild catalytic conditions; the performance of 2a was found to significantly surpass that of 1a and 3a. With the support of a systematic DFT study carried out on model silica surfaces, the observed differences in catalytic efficiency were correlated with an unprece-dented cooperative effect between two neighboring Nb centers on the surface of 2a. This is in an excellent agreement with our previous discoveries regarding the mechanism of the NbCl5 catalyzed cycloaddition in the homogeneous phase.en
dc.publisherAmerican Chemical Society (ACS)en
dc.relation.urlhttp://pubs.acs.org/doi/abs/10.1021/jacs.5b02872en
dc.rightsThis document is the Accepted Manuscript version of a Published Work that appeared in final form in Journal of the American Chemical Society, copyright © American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see http://pubs.acs.org/doi/abs/10.1021/jacs.5b02872.en
dc.titleCooperative effect by monopodal silica-supported niobium com-plexes pairs enhancing catalytic cyclic carbonate productionen
dc.typeArticleen
dc.contributor.departmentKAUST Catalysis Center (KCC)en
dc.identifier.journalJournal of the American Chemical Societyen
dc.eprint.versionPost-printen
dc.contributor.institutionUniversité de Lyon, (CNRS/ENS-Lyon/UCB Lyon 1), Centre de RMN à Très Hauts Champs, 5 rue de la Doua, 69100 Villeurbanne, France.en
dc.contributor.institutionInstitut de Química Computacional, Department de Química, Universitat de Girona, Campus de Montilivi , E-17071 Girona, Spain.en
dc.contributor.institutionInstitut des Sciences et Ingénierie Chimiques, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerlanden
kaust.authorD'Elia, Valerioen
kaust.authorDong, Hailinen
kaust.authorVummaleti, Sai Vikrama Chaitanyaen
kaust.authorMinenkov, Yuryen
kaust.authorAbou-Hamad, Edyen
kaust.authorPelletier, Jeremieen
kaust.authorCavallo, Luigien
kaust.authorBasset, Jean-Marieen
kaust.authorPoater, Alberten
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