Probing the efficiency of thermal and photochemical bond homolysis in functionalized nanostructured SBA-15 silicas.
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| Title: | Probing the efficiency of thermal and photochemical bond homolysis in functionalized nanostructured SBA-15 silicas. |
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| Authors: | Nabokoff, Pierre1 (AUTHOR), Gastaldi, Stéphane1 (AUTHOR) stephane.gastaldi@univ-amu.fr, Besson, Eric1 (AUTHOR) eric.besson@univ-amu.fr |
| Source: | Microporous & Mesoporous Materials. Feb2021, Vol. 311, pN.PAG-N.PAG. 1p. |
| Subjects: | Homolysis, Thermal efficiency, Mesoporous silica, Silica, Sol-gel processes, Alkoxyamines |
| Abstract: | The formation of radical species in solution can be triggered through thermal or photochemical activation of a suitable precursor. This EPR study aimed to establish if these two activation modes were as effective in mesoporous silicas as in solution. First, a calibration system was devised and validated to reliably quantify the radical formation. Alkoxyamines were selected to generate stable nitroxyl radicals upon heating or irradiation. Thanks to direct synthesis by the sol-gel process, these precursors were selectively located on the pore surface or in the framework of mesoporous silicas. The thermal or photo-chemical activation of the functionalized materials showed that nitroxides were formed in yields comparable to those observed in solution. No significant differences were observed with the implementation of these activation modes between the solution and the mesoporous silicas. Moreover, the thermal experiments enabled to measure the C–O bond dissociation constants of alkoxyamines covalently anchored to a nanostructured silica, their values were in the same order of magnitude than those determined in solution. Image 1 • Synthesis of thermally and/or photo-chemically activable alkoxyamine anchored SBA-15. • Evidences for a homolysis reaction as efficient on silica than in solution, whatever the thermal or photochemical conditions. • First determination of dissociation constants of alkoxyamines in functionalized mesoporous silicas. • First proof for photochemical TEMPO-H bond homolysis. [ABSTRACT FROM AUTHOR] |
| Copyright of Microporous & Mesoporous Materials is the property of Elsevier B.V. and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.) | |
| Database: | Engineering Source |
| FullText | Text: Availability: 0 |
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| Header | DbId: egs DbLabel: Engineering Source An: 147505312 AccessLevel: 6 PubType: Academic Journal PubTypeId: academicJournal PreciseRelevancyScore: 0 |
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| Items | – Name: Title Label: Title Group: Ti Data: Probing the efficiency of thermal and photochemical bond homolysis in functionalized nanostructured SBA-15 silicas. – Name: Author Label: Authors Group: Au Data: <searchLink fieldCode="AR" term="%22Nabokoff%2C+Pierre%22">Nabokoff, Pierre</searchLink><relatesTo>1</relatesTo> (AUTHOR)<br /><searchLink fieldCode="AR" term="%22Gastaldi%2C+Stéphane%22">Gastaldi, Stéphane</searchLink><relatesTo>1</relatesTo> (AUTHOR)<i> stephane.gastaldi@univ-amu.fr</i><br /><searchLink fieldCode="AR" term="%22Besson%2C+Eric%22">Besson, Eric</searchLink><relatesTo>1</relatesTo> (AUTHOR)<i> eric.besson@univ-amu.fr</i> – Name: TitleSource Label: Source Group: Src Data: <searchLink fieldCode="JN" term="%22Microporous+%26+Mesoporous+Materials%22">Microporous & Mesoporous Materials</searchLink>. Feb2021, Vol. 311, pN.PAG-N.PAG. 1p. – Name: Subject Label: Subjects Group: Su Data: <searchLink fieldCode="DE" term="%22Homolysis%22">Homolysis</searchLink><br /><searchLink fieldCode="DE" term="%22Thermal+efficiency%22">Thermal efficiency</searchLink><br /><searchLink fieldCode="DE" term="%22Mesoporous+silica%22">Mesoporous silica</searchLink><br /><searchLink fieldCode="DE" term="%22Silica%22">Silica</searchLink><br /><searchLink fieldCode="DE" term="%22Sol-gel+processes%22">Sol-gel processes</searchLink><br /><searchLink fieldCode="DE" term="%22Alkoxyamines%22">Alkoxyamines</searchLink> – Name: Abstract Label: Abstract Group: Ab Data: The formation of radical species in solution can be triggered through thermal or photochemical activation of a suitable precursor. This EPR study aimed to establish if these two activation modes were as effective in mesoporous silicas as in solution. First, a calibration system was devised and validated to reliably quantify the radical formation. Alkoxyamines were selected to generate stable nitroxyl radicals upon heating or irradiation. Thanks to direct synthesis by the sol-gel process, these precursors were selectively located on the pore surface or in the framework of mesoporous silicas. The thermal or photo-chemical activation of the functionalized materials showed that nitroxides were formed in yields comparable to those observed in solution. No significant differences were observed with the implementation of these activation modes between the solution and the mesoporous silicas. Moreover, the thermal experiments enabled to measure the C–O bond dissociation constants of alkoxyamines covalently anchored to a nanostructured silica, their values were in the same order of magnitude than those determined in solution. Image 1 • Synthesis of thermally and/or photo-chemically activable alkoxyamine anchored SBA-15. • Evidences for a homolysis reaction as efficient on silica than in solution, whatever the thermal or photochemical conditions. • First determination of dissociation constants of alkoxyamines in functionalized mesoporous silicas. • First proof for photochemical TEMPO-H bond homolysis. [ABSTRACT FROM AUTHOR] – Name: AbstractSuppliedCopyright Label: Group: Ab Data: <i>Copyright of Microporous & Mesoporous Materials is the property of Elsevier B.V. and its content may not be copied or emailed to multiple sites without the copyright holder's express written permission. Additionally, content may not be used with any artificial intelligence tools or machine learning technologies. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract.</i> (Copyright applies to all Abstracts.) |
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| RecordInfo | BibRecord: BibEntity: Identifiers: – Type: doi Value: 10.1016/j.micromeso.2020.110674 Languages: – Code: eng Text: English PhysicalDescription: Pagination: PageCount: 1 StartPage: N.PAG Subjects: – SubjectFull: Homolysis Type: general – SubjectFull: Thermal efficiency Type: general – SubjectFull: Mesoporous silica Type: general – SubjectFull: Silica Type: general – SubjectFull: Sol-gel processes Type: general – SubjectFull: Alkoxyamines Type: general Titles: – TitleFull: Probing the efficiency of thermal and photochemical bond homolysis in functionalized nanostructured SBA-15 silicas. Type: main BibRelationships: HasContributorRelationships: – PersonEntity: Name: NameFull: Nabokoff, Pierre – PersonEntity: Name: NameFull: Gastaldi, Stéphane – PersonEntity: Name: NameFull: Besson, Eric IsPartOfRelationships: – BibEntity: Dates: – D: 01 M: 02 Text: Feb2021 Type: published Y: 2021 Identifiers: – Type: issn-print Value: 13871811 Numbering: – Type: volume Value: 311 Titles: – TitleFull: Microporous & Mesoporous Materials Type: main |
| ResultId | 1 |
