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Biswas K, Chen Q, Obermann S, Ma J, Soler-Polo D, Melidonie J, Barragán A, Sánchez-Grande A, Lauwaet K, Gallego JM, Miranda R, Écija D, Jelínek P, Feng X, Urgel JI. On-Surface Synthesis of Non-Benzenoid Nanographenes Embedding Azulene and Stone-Wales Topologies. Angew Chem Int Ed Engl 2024; 63:e202318185. [PMID: 38299925 DOI: 10.1002/anie.202318185] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2023] [Revised: 01/26/2024] [Accepted: 01/30/2024] [Indexed: 02/02/2024]
Abstract
The incorporation of non-benzenoid motifs in graphene nanostructures significantly impacts their properties, making them attractive for applications in carbon-based electronics. However, understanding how specific non-benzenoid structures influence their properties remains limited, and further investigations are needed to fully comprehend their implications. Here, we report an on-surface synthetic strategy toward fabricating non-benzenoid nanographenes containing different combinations of pentagonal and heptagonal rings. Their structure and electronic properties were investigated via scanning tunneling microscopy and spectroscopy, complemented by computational investigations. After thermal activation of the precursor P on the Au(111) surface, we detected two major nanographene products. Nanographene Aa-a embeds two azulene units formed through oxidative ring-closure of methyl substituents, while Aa-s contains one azulene unit and one Stone-Wales defect, formed by the combination of oxidative ring-closure and skeletal ring-rearrangement reactions. Aa-a exhibits an antiferromagnetic ground state with the highest magnetic exchange coupling reported up to date for a non-benzenoid containing nanographene, coexisting with side-products with closed shell configurations resulted from the combination of ring-closure and ring-rearragement reactions (Ba-a , Ba-s , Bs-a and Bs-s ). Our results provide insights into the single gold atom assisted synthesis of novel NGs containing non-benzenoid motifs and their tailored electronic/magnetic properties.
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Affiliation(s)
- Kalyan Biswas
- IMDEA Nanoscience, C/Faraday 9, Campus de Cantoblanco, 28049, Madrid, Spain
| | - Qifan Chen
- Institute of Physics of the Czech Academy of Science, CZ-16253, Praha, Czech Republic
- Faculty of Mathematics and Physics, Charles University, V Holešovičkách 2, 180 00, Praha, Czech Republic
| | - Sebastian Obermann
- Center for Advancing Electronics Dresden (cfaed) & Faculty of Chemistry and Food Chemistry, Technische Universität Dresden, D-01069, Dresden, Germany
| | - Ji Ma
- Center for Advancing Electronics Dresden (cfaed) & Faculty of Chemistry and Food Chemistry, Technische Universität Dresden, D-01069, Dresden, Germany
- Max Planck Institute of Microstructure Physics, Weinberg 2, 06120, Halle, Germany
| | - Diego Soler-Polo
- Institute of Physics of the Czech Academy of Science, CZ-16253, Praha, Czech Republic
| | - Jason Melidonie
- Center for Advancing Electronics Dresden (cfaed) & Faculty of Chemistry and Food Chemistry, Technische Universität Dresden, D-01069, Dresden, Germany
| | - Ana Barragán
- IMDEA Nanoscience, C/Faraday 9, Campus de Cantoblanco, 28049, Madrid, Spain
| | - Ana Sánchez-Grande
- IMDEA Nanoscience, C/Faraday 9, Campus de Cantoblanco, 28049, Madrid, Spain
| | - Koen Lauwaet
- IMDEA Nanoscience, C/Faraday 9, Campus de Cantoblanco, 28049, Madrid, Spain
| | - José M Gallego
- Instituto de Ciencia de Materiales de Madrid (ICMM), CSIC, Cantoblanco, 28049, Madrid, Spain
| | - Rodolfo Miranda
- IMDEA Nanoscience, C/Faraday 9, Campus de Cantoblanco, 28049, Madrid, Spain
- Departamento de Física de la Materia Condensada, Universidad Autónoma de Madrid, 28049, Madrid, Spain
| | - David Écija
- IMDEA Nanoscience, C/Faraday 9, Campus de Cantoblanco, 28049, Madrid, Spain
- Unidad de Nanomateriales avanzados, IMDEA Nanoscience, Unidad asociada al CSIC por el ICMM, 28049, Madrid, Spain
| | - Pavel Jelínek
- Institute of Physics of the Czech Academy of Science, CZ-16253, Praha, Czech Republic
- Regional Centre of Advanced Technologies and Materials, Palacký University Olomouc, 771 46, Olomouc, Czech Republic
| | - Xinliang Feng
- Center for Advancing Electronics Dresden (cfaed) & Faculty of Chemistry and Food Chemistry, Technische Universität Dresden, D-01069, Dresden, Germany
- Max Planck Institute of Microstructure Physics, Weinberg 2, 06120, Halle, Germany
| | - José I Urgel
- IMDEA Nanoscience, C/Faraday 9, Campus de Cantoblanco, 28049, Madrid, Spain
- Unidad de Nanomateriales avanzados, IMDEA Nanoscience, Unidad asociada al CSIC por el ICMM, 28049, Madrid, Spain
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Wu F, Barragán A, Gallardo A, Yang L, Biswas K, Écija D, Mendieta-Moreno JI, Urgel JI, Ma J, Feng X. Structural Expansion of Cyclohepta[def]fluorene towards Azulene-Embedded Non-Benzenoid Nanographenes. Chemistry 2023; 29:e202301739. [PMID: 37339368 DOI: 10.1002/chem.202301739] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Revised: 06/20/2023] [Accepted: 06/20/2023] [Indexed: 06/22/2023]
Abstract
Non-benzenoid non-alternant nanographenes (NGs) have attracted increasing attention on account of their distinct electronic and structural features in comparison to their isomeric benzenoid counterparts. In this work, we present a series of unprecedented azulene-embedded NGs on Au(111) during the attempted synthesis of cyclohepta[def]fluorene-based high-spin non-Kekulé structure. Comprehensive scanning tunneling microscopy (STM) and non-contact atomic force microscopy (nc-AFM) evidence the structures and conformations of these unexpected products. The dynamics of the precursor bearing 9-(2,6-dimethylphenyl)anthracene and dihydro-dibenzo-cyclohepta[def]fluorene units and its reaction products on the surface are analyzed by density functional theory (DFT) and molecular dynamics (MD) simulations. Our study sheds light on the fundamental understanding of precursor design for the fabrication of π-extended non-benzenoid NGs on a metal surface.
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Affiliation(s)
- Fupeng Wu
- Max Planck Institute of Microstructure Physics, Weinberg 2, 06120, Halle, Germany
- Center for Advancing Electronics Dresden (cfaed) &, Faculty of Chemistry and Food Chemistry, Technische Universität Dresden, Mommsenstrasse 4, 01062, Dresden, Germany
| | - Ana Barragán
- IMDEA Nanoscience, C/Faraday 9, Campus de Cantoblanco, 28049, Madrid, Spain
| | - Aurelio Gallardo
- IMDEA Nanoscience, C/Faraday 9, Campus de Cantoblanco, 28049, Madrid, Spain
| | - Lin Yang
- Center for Advancing Electronics Dresden (cfaed) &, Faculty of Chemistry and Food Chemistry, Technische Universität Dresden, Mommsenstrasse 4, 01062, Dresden, Germany
| | - Kalyan Biswas
- IMDEA Nanoscience, C/Faraday 9, Campus de Cantoblanco, 28049, Madrid, Spain
| | - David Écija
- IMDEA Nanoscience, C/Faraday 9, Campus de Cantoblanco, 28049, Madrid, Spain
| | - Jesús I Mendieta-Moreno
- Departamento de Física Teórica de la Materia Condensada, Universidad Autónoma de Madrid, 28049, Madrid, Spain
| | - José I Urgel
- IMDEA Nanoscience, C/Faraday 9, Campus de Cantoblanco, 28049, Madrid, Spain
| | - Ji Ma
- Max Planck Institute of Microstructure Physics, Weinberg 2, 06120, Halle, Germany
- Center for Advancing Electronics Dresden (cfaed) &, Faculty of Chemistry and Food Chemistry, Technische Universität Dresden, Mommsenstrasse 4, 01062, Dresden, Germany
| | - Xinliang Feng
- Max Planck Institute of Microstructure Physics, Weinberg 2, 06120, Halle, Germany
- Center for Advancing Electronics Dresden (cfaed) &, Faculty of Chemistry and Food Chemistry, Technische Universität Dresden, Mommsenstrasse 4, 01062, Dresden, Germany
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Cahlík A, Liu D, Zengin B, Taskin M, Schwenk J, Natterer FD. A versatile platform for graphene nanoribbon synthesis, electronic decoupling, and spin polarized measurements. NANOSCALE ADVANCES 2023; 5:1722-1728. [PMID: 36926566 PMCID: PMC10012868 DOI: 10.1039/d2na00668e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/29/2022] [Accepted: 02/02/2023] [Indexed: 06/18/2023]
Abstract
The on-surface synthesis of nano-graphenes has led the charge in prototyping structures with perspectives beyond silicon-based technology. Following reports of open-shell systems in graphene-nanoribbons (GNRs), a flurry of research activity was directed at investigating their magnetic properties with a keen eye for spintronic applications. Although the synthesis of nano-graphenes is usually carried out on Au(111), the substrate is difficult to use for electronic decoupling and spin-polarized measurements. Using a binary alloy Cu3Au(111), we show possibilities for gold-like on-surface synthesis compatible with spin polarization and electronic decoupling known from copper. We prepare copper oxide layers, demonstrate the synthesis of GNRs, and grow thermally stable magnetic Co islands. We functionalize the tip of a scanning tunneling microscope with carbon-monoxide, nickelocene, or attach Co clusters for high-resolution imaging, magnetic sensing, or spin-polarized measurements. This versatile platform will be a valuable tool in the advanced study of magnetic nano-graphenes.
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Affiliation(s)
- Aleš Cahlík
- Department of Physics, University of Zurich Winterthurerstrasse 190 CH-8057 Zurich Switzerland
| | - Danyang Liu
- Department of Physics, University of Zurich Winterthurerstrasse 190 CH-8057 Zurich Switzerland
| | - Berk Zengin
- Department of Physics, University of Zurich Winterthurerstrasse 190 CH-8057 Zurich Switzerland
| | - Mert Taskin
- Department of Physics, University of Zurich Winterthurerstrasse 190 CH-8057 Zurich Switzerland
| | - Johannes Schwenk
- Institute of Physics, EPFL Station 3 CH-1015 Lausanne Switzerland
| | - Fabian Donat Natterer
- Department of Physics, University of Zurich Winterthurerstrasse 190 CH-8057 Zurich Switzerland
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Steering Large Magnetic Exchange Coupling in Nanographenes near the Closed-Shell to Open-Shell Transition. J Am Chem Soc 2023; 145:2968-2974. [PMID: 36708335 DOI: 10.1021/jacs.2c11431] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
The design of open-shell carbon-based nanomaterials is at the vanguard of materials science, steered by their beneficial magnetic properties like weaker spin-orbit coupling than that of transition metal atoms and larger spin delocalization, which are of potential relevance for future spintronics and quantum technologies. A key parameter in magnetic materials is the magnetic exchange coupling (MEC) between unpaired spins, which should be large enough to allow device operation at practical temperatures. In this work, we theoretically and experimentally explore three distinct families of nanographenes (NGs) (A, B, and C) featuring majority zigzag peripheries. Through many-body calculations, we identify a transition from a closed-shell ground state to an open-shell ground state upon an increase of the molecular size. Our predictions indicate that the largest MEC for open-shell NGs occurs in proximity to the transition between closed-shell and open-shell states. Such predictions are corroborated by the on-surface syntheses and structural, electronic, and magnetic characterizations of three NGs (A[3,5], B[4,5], and C[4,3]), which are the smallest open-shell systems in their respective chemical families and are thus located the closest to the transition boundary. Notably, two of the NGs (B[4,5] and C[4,3]) feature record values of MEC (close to 200 meV) measured on the Au(111) surface. Our strategy for maximizing the MEC provides perspectives for designing carbon nanomaterials with robust magnetic ground states.
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