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Pfund B, Gejsnæs-Schaad D, Lazarevski B, Wenger OS. Picosecond reactions of excited radical ion super-reductants. Nat Commun 2024; 15:4738. [PMID: 38834625 DOI: 10.1038/s41467-024-49006-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2024] [Accepted: 05/21/2024] [Indexed: 06/06/2024] Open
Abstract
Classical photochemistry requires nanosecond excited-state lifetimes for diffusion-controlled reactions. Excited radicals with picosecond lifetimes have been implied by numerous photoredox studies, and controversy has arisen as to whether they can actually be catalytically active. We provide direct evidence for the elusive pre-association between radical ions and substrate molecules, enabling photoinduced electron transfer beyond the diffusion limit. A strategy based on two distinct light absorbers, mimicking the natural photosystems I and II, is used to generate excited radicals, unleashing extreme reduction power and activating C(sp2)-Cl and C(sp2)-F bonds. Our findings provide a long-sought mechanistic understanding for many previous synthetically-oriented works and permit more rational future photoredox reaction development. The newly developed excitation strategy pushes the current limits of reactions based on multi-photon excitation and very short-lived but highly redox active species.
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Affiliation(s)
- Björn Pfund
- Department of Chemistry, University of Basel, Basel, Switzerland
| | | | - Bruno Lazarevski
- Department of Chemistry, University of Basel, Basel, Switzerland
| | - Oliver S Wenger
- Department of Chemistry, University of Basel, Basel, Switzerland.
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Mani T, Grills DC, Newton MD, Miller JR. Electron Localization of Anions Probed by Nitrile Vibrations. J Am Chem Soc 2015; 137:10979-91. [DOI: 10.1021/jacs.5b04648] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Tomoyasu Mani
- Chemistry Department, Brookhaven National Laboratory, Upton, New York 11973-5000, United States
| | - David C. Grills
- Chemistry Department, Brookhaven National Laboratory, Upton, New York 11973-5000, United States
| | - Marshall D. Newton
- Chemistry Department, Brookhaven National Laboratory, Upton, New York 11973-5000, United States
| | - John R. Miller
- Chemistry Department, Brookhaven National Laboratory, Upton, New York 11973-5000, United States
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Palma CA, Joshi S, Hoh T, Ecija D, Barth JV, Auwärter W. Two-level spatial modulation of vibronic conductance in conjugated oligophenylenes on boron nitride. NANO LETTERS 2015; 15:2242-8. [PMID: 25756645 DOI: 10.1021/nl503956p] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Intramolecular current-induced vibronic excitations are reported in highly ordered monolayers of quaterphenylene dicarbonitriles at an electronically patterned boron nitride on copper platform (BN/Cu(111)). A first level of spatially modulated conductance at the nanometer-scale is induced by the substrate. Moreover, a second level of conductance variations at the molecular level is found. Low temperature scanning tunneling microscopy studies in conjunction with molecular dynamics calculations reveal collective amplification of the molecule's interphenylene torsion angles in the monolayer. Librational modes influencing these torsion angles are identified as initial excitations during vibronic conductance. Density functional theory is used to map phenylene breathing modes and other vibrational excitations that are suggested to be at the origin of the submolecular features during vibronic conductance.
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Affiliation(s)
- Carlos-Andres Palma
- §Physik-Department E20, Technische Universität München, D-85748 Garching, Germany
| | - Sushobhan Joshi
- §Physik-Department E20, Technische Universität München, D-85748 Garching, Germany
| | - Tobias Hoh
- §Physik-Department E20, Technische Universität München, D-85748 Garching, Germany
| | - David Ecija
- §Physik-Department E20, Technische Universität München, D-85748 Garching, Germany
- †IMDEA Nanoscience, 28049 Madrid, Spain
| | - Johannes V Barth
- §Physik-Department E20, Technische Universität München, D-85748 Garching, Germany
| | - Willi Auwärter
- §Physik-Department E20, Technische Universität München, D-85748 Garching, Germany
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4
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Hoekstra RM, Chen YT, Kiesz MD, Telo JP, Stephenson RM, Nelsen SF, Zink JI. Resonance Raman spectroscopic study of solvent-dependent coexistence of localized and delocalized dinitroaromatic radical anions. CAN J CHEM 2014. [DOI: 10.1139/cjc-2014-0058] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Optical absorption spectra of three dinitroaromatic radical anions, 2,7-dinitro-9,9-dimethylfluorene (1•−), 4,4′-dinitrobiphenyl (2•−), and 4,4′-dinitrotolane (3•−) in solvents THF, HMPA, and MeCN show both an unresolved broad band characteristic of charge-localized mixed valence species (Robin-Day classification Class II), and a vibronically structured band of the delocalized species (Class III). With decreasing solvent reorganization energy, a greater portion of the compounds become charge-delocalized. In particular, 1•− with the greatest coupling, is almost entirely composed of the delocalized species in all solvents. An intense Raman mode is used to identify the charge-bearing unit as the nitrobenzene moiety. Resonance Raman profiles are utilized to gain detailed information of vibrational modes. The out-of-phase ring lengthening stretch mode is observed to be enhanced at higher excitation energies, corresponding to the absorption band of the Class II species, while the in-phase ring lengthening stretch mode, a totally symmetric vibration, is most strongly enhanced in the absorption region of the Class III species. Resonance Raman profiles support the solvent-dependent coexistence of Class II and Class III molecules of the same chemical composition.
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Affiliation(s)
- Ryan M. Hoekstra
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA 90095-1569, USA
| | - Yen-Ting Chen
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA 90095-1569, USA
| | - Matthew D. Kiesz
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA 90095-1569, USA
| | - João P. Telo
- Centro de Química Estrutural, Instituto Superior Técnico, Av. Rovisco Pais, 1049-001 Lisboa, Portugal
| | - Rachel M. Stephenson
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA 90095-1569, USA
| | - Stephen F. Nelsen
- Department of Chemistry and Molecular Structure Laboratory, University of Wisconsin, 1101 University Avenue, Madison, WI 53706-1396, USA
| | - Jeffrey I. Zink
- Department of Chemistry and Biochemistry, University of California, Los Angeles, CA 90095-1569, USA
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Moneo Á, Justino GC, Carvalho MFNN, Oliveira MC, Antunes AMM, Bléger D, Hecht S, Telo JP. Electronic Communication in Linear Oligo(azobenzene) Radical Anions. J Phys Chem A 2013; 117:14056-64. [DOI: 10.1021/jp407099c] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Affiliation(s)
- Álvaro Moneo
- Centro de Química Estrutural, Instituto Superior
Técnico, Universidade de Lisboa, Av. Rovisco Pais, 1049-001 Lisboa, Portugal
| | - Gonçalo C. Justino
- Centro de Química Estrutural, Instituto Superior
Técnico, Universidade de Lisboa, Av. Rovisco Pais, 1049-001 Lisboa, Portugal
| | - M. Fernanda N. N. Carvalho
- Centro de Química Estrutural, Instituto Superior
Técnico, Universidade de Lisboa, Av. Rovisco Pais, 1049-001 Lisboa, Portugal
| | - M. Conceição Oliveira
- Centro de Química Estrutural, Instituto Superior
Técnico, Universidade de Lisboa, Av. Rovisco Pais, 1049-001 Lisboa, Portugal
| | - Alexandra M. M. Antunes
- Centro de Química Estrutural, Instituto Superior
Técnico, Universidade de Lisboa, Av. Rovisco Pais, 1049-001 Lisboa, Portugal
| | - David Bléger
- Department of Chemistry, Humboldt-Universität zu Berlin, Brook-Taylor-Strasse
2, 12489 Berlin, Germany
| | - Stefan Hecht
- Department of Chemistry, Humboldt-Universität zu Berlin, Brook-Taylor-Strasse
2, 12489 Berlin, Germany
| | - João P. Telo
- Centro de Química Estrutural, Instituto Superior
Técnico, Universidade de Lisboa, Av. Rovisco Pais, 1049-001 Lisboa, Portugal
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Moneo Á, Telo JP. Electron transfer within 1,3-dinitrobenzene radical anions: electron hopping or superexchange? J PHYS ORG CHEM 2013. [DOI: 10.1002/poc.2957] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Álvaro Moneo
- Centro de Química Estrutural, Instituto Superior Técnico; Technical University of Lisbon; Av. Rovisco Pais 1049-001 Lisboa Portugal
| | - João P. Telo
- Centro de Química Estrutural, Instituto Superior Técnico; Technical University of Lisbon; Av. Rovisco Pais 1049-001 Lisboa Portugal
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