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Schunke C, Schweer P, Engelage E, Austin D, Switzer ED, Rahman TS, Morgenstern K. Increased Selectivity in Photolytic Activation of Nanoassemblies Compared to Thermal Activation in On-Surface Ullmann Coupling. ACS NANO 2024; 18:11665-11674. [PMID: 38661485 DOI: 10.1021/acsnano.3c11509] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/26/2024]
Abstract
On-surface synthesis is a powerful method that has emerged recently to fabricate a large variety of atomically precise nanomaterials on surfaces based on polymerization. It is very successful for thermally activated reactions within the framework of heterogeneous catalysis. As a result, it often lacks selectivity. We propose to use selective activation of specific bonds as a crucial ingredient to synthesize desired molecules with high selectivity. In this approach, thermally nonaccessible products are expected to arise in photolytically activated on-surface reactions with high selectivity. We demonstrate for assembled 2,2'-dibromo biphenyl clusters on Cu(111) that the thermal and photolytic activations yield distinctly different products, combining submolecular resolution of individual product molecules in real-space imaging by scanning tunneling microscopy with chemical identification in X-ray photoelectron spectroscopy and supported by ab initio calculations. The photolytically activated Ullmann coupling of 2,2'-dibromo biphenyl is highly selective, with only one identified product. It starkly contrasts the thermal reaction, which yields various products because alternate pathways are activated at the reaction temperature. Our study extends on-surface synthesis to a directed formation of thermally inaccessible products by direct bond activation. It promises tailored reactions of nanomaterials within the framework of on-surface synthesis based on the photolytic activation of specific bonds.
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Affiliation(s)
- Christina Schunke
- Lehrstuhl für Physikalische Chemie I, Ruhr-Universität Bochum, Universitätsstraße 150, Bochum D-44801, Germany
| | - Paul Schweer
- Lehrstuhl für Physikalische Chemie I, Ruhr-Universität Bochum, Universitätsstraße 150, Bochum D-44801, Germany
| | - Elric Engelage
- Lehrstuhl für Organische Chemie II, Ruhr-Universität Bochum, Universitätsstraße 150, Bochum D-44801, Germany
| | - Dave Austin
- Department of Physics, University of Central Florida, Orlando, Florida 32816, United States
| | - Eric D Switzer
- Department of Physics, University of Central Florida, Orlando, Florida 32816, United States
| | - Talat S Rahman
- Department of Physics, University of Central Florida, Orlando, Florida 32816, United States
| | - Karina Morgenstern
- Lehrstuhl für Physikalische Chemie I, Ruhr-Universität Bochum, Universitätsstraße 150, Bochum D-44801, Germany
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Timm MJ, Leung L, Anggara K, Lim T, Hu Z, Latini S, Rubio A, Polanyi JC. Contrasting Efficiency of Electron-Induced Reaction at Cu(110) in Aliphatic and Aromatic Bromides. J Am Chem Soc 2020; 142:9453-9459. [PMID: 32329343 DOI: 10.1021/jacs.0c02851] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We report a comparative study of the electron-induced reaction of pentyl bromide (PeBr) and phenyl bromide (PhBr) on Cu(110) at 4.6 K, observed by scanning tunneling microscopy (STM). The induced dissociation of the intact adsorbed molecule for both reagents occurred at an energy of 2.0 eV, producing a hydrocarbon radical and a Br atom. Electron-induced C-Br bond dissociation was found to be a single-electron process for both reagents. The impulsive two-state (I2S) model was used to describe the Br atom recoil as due to molecular excitation to a repulsive anti-bonding state, in which recoil of the dissociation products occurred due to C·Br repulsion along the prior C-Br bond direction. The measured reaction yield was 3 orders of magnitude greater for PeBr, 2.0 × 10-7 reactive events per electron, than for PhBr with a yield of 1.7 × 10-10. The low yield of dissociation products from the aromatic PhBr was attributed to the presence of two additional anionic states below the 2.0 eV energy limit, absent for the aliphatic PeBr; these additional anionic states for PhBr could provide a pathway for electron transfer to the surface in the case of the aromatic, but not the aliphatic, anion. The consequent shorter lifetime of the repulsive aromatic anion of PhBr is consistent with the observation of shorter mean recoil distance (3.2 Å) of its Br dissociation product, as compared with the markedly longer recoil (8.7 Å) of Br observed from the anion of PeBr.
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Affiliation(s)
- Matthew J Timm
- Lash Miller Chemical Laboratories, Department of Chemistry and Institute of Optical Sciences, University of Toronto, 80 St. George Street, Toronto, Ontario M5H 3H6, Canada
| | - Lydie Leung
- Lash Miller Chemical Laboratories, Department of Chemistry and Institute of Optical Sciences, University of Toronto, 80 St. George Street, Toronto, Ontario M5H 3H6, Canada
| | - Kelvin Anggara
- Lash Miller Chemical Laboratories, Department of Chemistry and Institute of Optical Sciences, University of Toronto, 80 St. George Street, Toronto, Ontario M5H 3H6, Canada
| | - Tingbin Lim
- Lash Miller Chemical Laboratories, Department of Chemistry and Institute of Optical Sciences, University of Toronto, 80 St. George Street, Toronto, Ontario M5H 3H6, Canada
| | - Zhixin Hu
- Lash Miller Chemical Laboratories, Department of Chemistry and Institute of Optical Sciences, University of Toronto, 80 St. George Street, Toronto, Ontario M5H 3H6, Canada
| | - Simone Latini
- Max Planck Institute for the Structure and Dynamics of Matter, Luruper Chaussee 149, 22761 Hamburg, Germany.,Center for Free-Electron Laser Science and Department of Physics, University of Hamburg, Luruper Chaussee 149, 22761 Hamburg, Germany
| | - Angel Rubio
- Max Planck Institute for the Structure and Dynamics of Matter, Luruper Chaussee 149, 22761 Hamburg, Germany.,Center for Free-Electron Laser Science and Department of Physics, University of Hamburg, Luruper Chaussee 149, 22761 Hamburg, Germany
| | - John C Polanyi
- Lash Miller Chemical Laboratories, Department of Chemistry and Institute of Optical Sciences, University of Toronto, 80 St. George Street, Toronto, Ontario M5H 3H6, Canada
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Bertram C, Auburger P, Bockstedte M, Stähler J, Bovensiepen U, Morgenstern K. Impact of Electron Solvation on Ice Structures at the Molecular Scale. J Phys Chem Lett 2020; 11:1310-1316. [PMID: 31985230 DOI: 10.1021/acs.jpclett.9b03723] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Electron attachment and solvation at ice structures are well-known phenomena. The energy liberated in such events is commonly understood to cause temporary changes at such ice structures, but it may also trigger permanent modifications to a yet unknown extent. We determine the impact of electron solvation on D2O structures adsorbed on Cu(111) with low-temperature scanning tunneling microscopy, two-photon photoemission, and ab initio theory. Solvated electrons, generated by ultraviolet photons, lead not only to transient but also to permanent structural changes through the rearrangement of individual molecules. The persistent changes occur near sites with a high density of dangling OD groups that facilitate electron solvation. We conclude that energy dissipation during solvation triggers permanent molecular rearrangement via vibrational excitation.
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Affiliation(s)
- Cord Bertram
- Physical Chemistry I , Ruhr-Universität Bochum , D-44780 Bochum , Germany
- Faculty of Physics , University of Duisburg-Essen , Lotharstr. 1 , D-47048 Duisburg , Germany
| | - Philipp Auburger
- Solid State Theory , Friedrich-Alexander University Erlangen-Nürnberg , Staudtstr. 7B2 , D-91058 Erlangen , Germany
| | - Michel Bockstedte
- Solid State Theory , Friedrich-Alexander University Erlangen-Nürnberg , Staudtstr. 7B2 , D-91058 Erlangen , Germany
- Chemistry and Physics of Materials , University of Salzburg , Jakob-Haringer-Str. 2a , A-5020 Salzburg , Austria
| | - Julia Stähler
- Department of Physical Chemistry , Fritz Haber Institute of the Max Planck Society , Faradayweg 4-6 , D-14195 Berlin , Germany
- Department of Physics , Freie Universität Berlin , Arnimallee 14 , D-14195 Berlin , Germany
| | - Uwe Bovensiepen
- Faculty of Physics , University of Duisburg-Essen , Lotharstr. 1 , D-47048 Duisburg , Germany
- Department of Physics , Freie Universität Berlin , Arnimallee 14 , D-14195 Berlin , Germany
| | - Karina Morgenstern
- Physical Chemistry I , Ruhr-Universität Bochum , D-44780 Bochum , Germany
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Lemelin V, Bass AD, Cloutier P, Sanche L. Low energy (1-19 eV) electron scattering from condensed thymidine (dT) II: comparison of vibrational excitation cross sections with those of tetrahydrofuran and the recalibrated values of thymine. Phys Chem Chem Phys 2019; 21:23818-23825. [PMID: 31503272 DOI: 10.1039/c9cp03448j] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Recent measurements of absolute vibrational cross sections (CSs) for low-energy electron (LEE) scattering from condensed thymidine (dT) allows comparison with CSs of its constituents; thymine and tetrahydrofuran (THF). To facilitate this comparison, the vibrational CSs of condensed thymine were remeasured at six electron incident energies and a correction was applied to the earlier thymine CS values measured by Lévesque et al. [Nucl. Instrum. Methods Phys. Res., Sect. B, 2003, 208, 225]. The incident energy dependence of the CS of each vibrational mode of dT is compared with the corresponding modes in thymine and/or THF. It is found that the magnitude of the CSs of the thymine breathing mode and the C-C stretch mode of THF are greatly attenuated in dT. Finally, the magnitudes of the total vibrational CSs of each molecule are compared. Below 4 eV, the total vibrational CSs of dT is greater than each of its two constituents. Interestingly, at higher energy (>6 eV), the magnitude of the total vibrational CS of dT is roughly equal to that of THF and is greater than thymine by only 15% at 10 eV, showing that the CSs of dT cannot be approximated by the addition of the CSs of its constituents over the entire energy range. These comparisons are discussed in terms of the basic principles involved in the formation and decay of shape resonances, which are known to be responsible for major enhancements of LEE-induced vibrational excitation at low electron energies.
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Affiliation(s)
- V Lemelin
- Groupe en Sciences des Radiations, Département de Médecine Nucléaire et Radiobiologie, Faculté de Médecine et Sciences des radiations, Université de Sherbrooke, Québec J1H 5N4, Canada.
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Lemelin V, Bass AD, Cloutier P, Sanche L. Low energy (1-19 eV) electron scattering from condensed thymidine (dT) I: absolute vibrational excitation cross sections. Phys Chem Chem Phys 2019; 21:23808-23817. [PMID: 31503266 DOI: 10.1039/c9cp03447a] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Absolute cross sections (CSs) for vibrational excitation by electrons of energy between 1-19 eV scattering from condensed thymidine (dT) were measured by means of high-resolution electron energy loss spectroscopy (HREELS). The CSs were extracted from electron energy loss spectra of dT condensed on multilayers film of Ar held at about 20 K under ultra-high vacuum (∼1 × 10-11 Torr). dT is one of the most complex molecules to be studied in condensed phase by HREELS. The magnitudes of the vibrational CSs lie within the 10-17 cm2 range. Structures observed in the energy dependence of the vibrational CSs under 3 eV and around 4 eV were compared with previous results of gas- and solid-phase studies on dT and related molecules (e.g., thymine and tetrahydrofuran). These structures were attributed to the formation of shape resonances.
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Affiliation(s)
- V Lemelin
- Groupe en Sciences des Radiations, Département de Médecine Nucléaire et Radiobiologie, Faculté de Médecine et Sciences des radiations, Université de Sherbrooke, Québec J1H 5N4, Canada.
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Patera LL, Queck F, Scheuerer P, Moll N, Repp J. Accessing a Charged Intermediate State Involved in the Excitation of Single Molecules. PHYSICAL REVIEW LETTERS 2019; 123:016001. [PMID: 31386418 DOI: 10.1103/physrevlett.123.016001] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/18/2019] [Revised: 05/02/2019] [Indexed: 06/10/2023]
Abstract
Intermediate states are elusive to many experimental techniques due to their short lifetimes. Here, by performing single-electron alternate charging scanning tunneling microscopy of molecules on insulators, we accessed a charged intermediate state involved in the rapid toggling of individual metal phthalocyanines deposited on NaCl films. By stabilizing the transient species, we reveal how electron injection into the lowest unoccupied molecular orbital leads to a pronounced change in the adsorption geometry, characterized by a different azimuthal orientation. This observation allows clarifying the nature of the toggling process, unveiling the role of transient ionic states involved into fundamental processes occurring at interfaces.
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Affiliation(s)
- Laerte L Patera
- Institute of Experimental and Applied Physics, University of Regensburg, 93053 Regensburg, Germany
| | - Fabian Queck
- Institute of Experimental and Applied Physics, University of Regensburg, 93053 Regensburg, Germany
| | - Philipp Scheuerer
- Institute of Experimental and Applied Physics, University of Regensburg, 93053 Regensburg, Germany
| | - Nikolaj Moll
- IBM Research-Zurich, 8803 Rüschlikon, Switzerland
| | - Jascha Repp
- Institute of Experimental and Applied Physics, University of Regensburg, 93053 Regensburg, Germany
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