A Zirconium Photosensitizer with a Long-Lived Excited State: Mechanistic Insight into Photoinduced Single-Electron Transfer.
Time-resolved emission spectroscopy for the luminescent zirconium complex Zr(PDP)2 (MePDP = 2,6-bis(5-methyl-3-phenyl-1H-pyrrol-2-yl)pyridine) revealed a long-lived excited state with a lifetime τ = 325 ± 10 μs. Computational studies using time-dependent density functional theory were conducted to i...
| Published in: | Journal of the American Chemical Society Vol. 140; no. 18; pp. 5934 - 5948 |
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| Main Authors: | , , , |
| Format: | Article |
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American Chemical Society
5/9/2018
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| Online Access: | View this record in EBSCOhost |
| fields | @attributes: recordID: 1 pdfLink: plink: https://search.ebscohost.com/login.aspx?direct=true&db=hlh&AN=129582255&site=ehost-live header: @attributes: shortDbName: hlh uiTerm: 129582255 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: 5/9/2018 vid: 140 iid: 18 pid: 997 pub: American Chemical Society artinfo: ui: 129582255 10.1021/jacs.8b00742 ppf: 5934 ppct: 14 formats: tig: atl: A Zirconium Photosensitizer with a Long-Lived Excited State: Mechanistic Insight into Photoinduced Single-Electron Transfer. aug: au: Zhang, Yu Lee, Tia S. Petersen, Jeffrey L. Milsmann, Carsten affil: C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, West Virginia 26506, United States Department of Chemistry, Princeton University, Princeton, New Jersey 08544, United States su: Zirconium Photosensitizers Photoinduced electron transfer Emission spectroscopy Density functional theory sug: subj: Zirconium Photosensitizers Photoinduced electron transfer Emission spectroscopy Density functional theory ab: Time-resolved emission spectroscopy for the luminescent zirconium complex Zr(PDP)2 (MePDP = 2,6-bis(5-methyl-3-phenyl-1H-pyrrol-2-yl)pyridine) revealed a long-lived excited state with a lifetime τ = 325 ± 10 μs. Computational studies using time-dependent density functional theory were conducted to identify the nature of the luminescent excited state as a mixed triplet intraligand/ligandto- metal charge-transfer state. Stern--Volmer experiments showed a strong dependence of the quenching rate on the redox potential of the quencher indicating photoinduced single-electron transfer (SET) as the quenching pathway. Mechanistic investigations of the photocatalytic homocoupling of benzyl bromide allowed the detection of organic radical intermediates during turnover and provided further evidence for SET mediated by Zr(PDP). Isolation of the one-electron-reduced form of the photosensitizer, [Zr(PDP)], enabled studies of its electronic structure by a combination of experimental and computational techniques and confirmed its role as a strong reductant. Additionally, the role of the benzimidazolium hydride derivatives as two-electron sacrificial reductants during photoredox catalysis was investigated. In combination, the results presented in this report establish a detailed mechanistic picture of a photoredox catalytic reaction promoted by an earth-abundant early transition metal photosensitizer. 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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