Structure-Property Relationships for Tailoring Phenoxazines as Reducing Photoredox Catalysts.
Through the study of structure-property relationships using a combination of experimental and computational analyses, a number of phenoxazine derivatives have been developed as visible light absorbing, organic photoredox catalysts (PCs) with excited state reduction potentials rivaling those of highl...
| Publicado en: | Journal of the American Chemical Society Vol. 140; no. 15; pp. 5088 - 5102 |
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| Autores principales: | , , , , , |
| Formato: | Artículo |
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American Chemical Society
4/18/2018
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| Materias: | |
| Acceso en línea: | Ver este registro en EBSCOhost |
| fields | @attributes: recordID: 1 pdfLink: plink: https://search.ebscohost.com/login.aspx?direct=true&db=hlh&AN=129236685&site=ehost-live header: @attributes: shortDbName: hlh uiTerm: 129236685 longDbName: Humanities International Complete uiTag: AN controlInfo: bkinfo: jinfo: jid: 00027863 ACS jtl: Journal of the American Chemical Society issn: 00027863 maglogo: N pubinfo: dt: 4/18/2018 vid: 140 iid: 15 pid: 997 pub: American Chemical Society artinfo: ui: 129236685 10.1021/jacs.7b12074 ppf: 5088 ppct: 14 formats: tig: atl: Structure-Property Relationships for Tailoring Phenoxazines as Reducing Photoredox Catalysts. aug: au: McCarthy, Blaine G. Pearson, Ryan M. Chern-Hooi Lim Sartor, Steven M. Damrauer, Niels H. Miyake, Garret M. affil: Department of Chemistry, Colorado State University, Fort Collins, Colorado 80523-1872, United States Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado 80309-0215, United States Materials Science and Engineering, University of Colorado, Boulder, Colorado 80309-0215, United States su: Catalysts Visible spectra Time-dependent density functional theory Photoexcitation Polymerization sug: subj: Catalysts Visible spectra Time-dependent density functional theory Photoexcitation Polymerization ab: Through the study of structure-property relationships using a combination of experimental and computational analyses, a number of phenoxazine derivatives have been developed as visible light absorbing, organic photoredox catalysts (PCs) with excited state reduction potentials rivaling those of highly reducing transition metal PCs. Time-dependent density functional theory (TD-DFT) computational modeling of the photoexcitation of N-aryl and core modified phenoxazines guided the design of PCs with absorption profiles in the visible regime. In accordance with our previous work with N,N-diaryl dihydrophenazines, characterization of noncore modified N-aryl phenoxazines in the excited state demonstrated that the nature of the N-aryl substituent dictates the ability of the PC to access a charge transfer excited state. However, our current analysis of core modified phenoxazines revealed that these molecules can access a different type of CT excited state which we posit involves a core substituent as the electron acceptor. Modification of the core of phenoxazine derivatives with electron-donating and electron-withdrawing substituents was used to alter triplet energies, excited state reduction potentials, and oxidation potentials of the phenoxazine derivatives. The catalytic activity of these molecules was explored using organocatalyzed atom transfer radical polymerization (O-ATRP) for the synthesis of poly(methyl methacrylate) (PMMA) using white light irradiation. All of the derivatives were determined to be suitable PCs for O-ATRP as indicated by a linear growth of polymer molecular weight as a function of monomer conversion and the ability to synthesize PMMA with moderate to low dispersity (dispersity less than or equal to 1.5) and initiator efficiencies typically greater than 70% at high conversions. However, only PCs that exhibit strong absorption of visible light and strong triplet excited state reduction potentials maintain control over the polymerization during the entire course of the reaction. The structure-property relationships established here will enable the application of these organic PCs for O-ATRP and other photoredox-catalyzed small molecule and polymer syntheses. pubtype: Academic Journal doctype: Article src: R language: English refInfo: copyright: @attributes: flag: Y dt: @attributes: year: 2018 holdings: @attributes: islocal: N |
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