1
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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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2
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Zhang H, Lu J, Zhao XJ, Li B, Zhou H, Zhang Y, Niu G, Fu B, Gao L, Tan YZ, Cai J. Length-Dependent Magnetic Evolution of Anthenes on Au(111). Angew Chem Int Ed Engl 2023; 62:e202315216. [PMID: 37933811 DOI: 10.1002/anie.202315216] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2023] [Revised: 11/06/2023] [Accepted: 11/07/2023] [Indexed: 11/08/2023]
Abstract
Nanographenes with zigzag edges, for example, anthenes, exhibit a unique nonbonding π-electron state, which can be described as a spin-polarized edge state that yields specific magnetic ground state. However, prior researches on the magnetism of anthenes with varying lengths on a surface is lacking. This study systematically fabricated anthenes with inherent zigzag carbon atoms of different lengths ranging from bisanthene to hexanthene. Their magnetic evolution on the Au(111) surface was analyzed through bond-resolved scanning probe techniques and density functional theory calculations. The analyses revealed a transition in magnetic properties associated with the length of the anthenes, arising from the imbalance between hybridization energy and the Coulomb repulsion between valence electrons. With the increasing length of the anthenes, the ground state transforms gradually from a closed-shell to an antiferromagnetic open-shell singlet, exhibiting a weak exchange coupling of 4 meV and a charge transfer-induced doublet. Therefore, this study formulated a chemically tunable platform to explore size-dependent π magnetism at the atomic scale, providing a framework for research in organic spintronics.
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Affiliation(s)
- Hui Zhang
- Faculty of Materials Science and Engineering, Kunming University of Science and Technology, Kunming, 650093, China
| | - Jianchen Lu
- Faculty of Materials Science and Engineering, Kunming University of Science and Technology, Kunming, 650093, China
| | - Xin-Jing Zhao
- State Key Laboratory for Physical Chemistry of Solid Surfaces, Collaborative Innovation Center of Chemistry for Energy Materials, and Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005, China
| | - Baijin Li
- Faculty of Materials Science and Engineering, Kunming University of Science and Technology, Kunming, 650093, China
| | - Hangjing Zhou
- Faculty of Materials Science and Engineering, Kunming University of Science and Technology, Kunming, 650093, China
| | - Yong Zhang
- Faculty of Materials Science and Engineering, Kunming University of Science and Technology, Kunming, 650093, China
| | - Gefei Niu
- Faculty of Materials Science and Engineering, Kunming University of Science and Technology, Kunming, 650093, China
| | - Boyu Fu
- Faculty of Materials Science and Engineering, Kunming University of Science and Technology, Kunming, 650093, China
| | - Lei Gao
- Faculty of Science, Kunming University of Science and Technology, Kunming, 650500, China
| | - Yuan-Zhi Tan
- State Key Laboratory for Physical Chemistry of Solid Surfaces, Collaborative Innovation Center of Chemistry for Energy Materials, and Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005, China
| | - Jinming Cai
- Faculty of Materials Science and Engineering, Kunming University of Science and Technology, Kunming, 650093, China
- Southwest United Graduate School, Kunming, 650093, China
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3
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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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Zheng F, Lu J, Zhu Z, Jiang H, Yan Y, He Y, Yuan S, Sun Q. Predicting Molecular Self-Assembly on Metal Surfaces Using Graph Neural Networks Based on Experimental Data Sets. ACS NANO 2023; 17:17545-17553. [PMID: 37611029 DOI: 10.1021/acsnano.3c06405] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/25/2023]
Abstract
The application of supramolecular chemistry on solid surfaces has received extensive attention in the past few decades. To date, combining experiments with quantum mechanical or molecular dynamic methods represents the key strategy to explore the molecular self-assembled structures, which is, however, often laborious. Recently, machine learning (ML) has become one of the most exciting tools in material research, allowing for both efficiency and accuracy in predicting molecular properties. In this work, we constructed a graph neural network to predict the self-assembly of functional polycyclic aromatic hydrocarbons (PAHs) on metal surfaces. Using scanning tunneling microscopy (STM), we characterized the self-assembled nanostructures of a homologous series of PAH molecules on different metal surfaces to construct an experimental data set for model training. Compared with traditional ML algorithms, our model exhibits better predictive performance. Finally, the generalization of the model is further verified by comparing the ML predictions and experimental results of different functionalized molecule. Our results demonstrate training experimental data sets to produce a predictive ML model of molecular self-assembly with generalization performance, which allows for the predictive design of nanostructures with functional molecules.
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Affiliation(s)
- Fengru Zheng
- Materials Genome Institute, Shanghai University, 200444 Shanghai, China
| | - Jiayi Lu
- Materials Genome Institute, Shanghai University, 200444 Shanghai, China
| | - Zhiwen Zhu
- Materials Genome Institute, Shanghai University, 200444 Shanghai, China
| | - Hao Jiang
- Materials Genome Institute, Shanghai University, 200444 Shanghai, China
| | - Yuyi Yan
- Materials Genome Institute, Shanghai University, 200444 Shanghai, China
| | - Yu He
- Materials Genome Institute, Shanghai University, 200444 Shanghai, China
| | - Shaoxuan Yuan
- Materials Genome Institute, Shanghai University, 200444 Shanghai, China
| | - Qiang Sun
- Materials Genome Institute, Shanghai University, 200444 Shanghai, China
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5
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Closed-shell and open-shell dual nature of singlet diradical compounds. PURE APPL CHEM 2023. [DOI: 10.1515/pac-2023-0114] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/09/2023]
Abstract
Abstract
Unlike triplet diradicals, singlet diradicals can vary in diradical character from 0 % to 100 % depending on linker units that allow two formally unpaired electrons to couple covalently. In principle, the electronic structure of singlet diradicals can be described as a quantum superposition of closed-shell and open-shell structures. This means that, depending on the external environment, singlet diradicals can behave as either closed-shell or open-shell species. This paper summarizes our progress in understanding the electronic structure of π-conjugated singlet diradical molecules in terms of closed-shell and open-shell dual nature. We first discuss the coexistence of intra- and intermolecular covalent bonding interactions in the π-dimer of a singlet diradical molecule. The intra- and intermolecular coupling of two formally unpaired electrons are related to closed-shell and open-shell nature of singlet diradical, respectively. Then we demonstrate the coexistence of the covalent bonding interactions in the one-dimensional stack of singlet diradical molecules having different diradical character. The relative strength of the interactions is varied with the magnitude of singlet diradical index y
0. Finally, we show the dual reactivity of a singlet diradical molecule, which undergoes rapid [4 + 2] and [4 + 4] cycloaddition reactions in the dark at room temperature. Closed-shell and open-shell nature endow the singlet diradical molecule with the reaction manner as diene and diradical species, respectively.
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6
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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: 10] [Impact Index Per Article: 10.0] [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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de Oteyza DG, Frederiksen T. Carbon-based nanostructures as a versatile platform for tunable π-magnetism. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2022; 34:443001. [PMID: 35977474 DOI: 10.1088/1361-648x/ac8a7f] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/08/2022] [Accepted: 08/17/2022] [Indexed: 06/15/2023]
Abstract
Emergence ofπ-magnetism in open-shell nanographenes has been theoretically predicted decades ago but their experimental characterization was elusive due to the strong chemical reactivity that makes their synthesis and stabilization difficult. In recent years, on-surface synthesis under vacuum conditions has provided unprecedented opportunities for atomically precise engineering of nanographenes, which in combination with scanning probe techniques have led to a substantial progress in our capabilities to realize localized electron spin states and to control electron spin interactions at the atomic scale. Here we review the essential concepts and the remarkable advances in the last few years, and outline the versatility of carbon-basedπ-magnetic materials as an interesting platform for applications in spintronics and quantum technologies.
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Affiliation(s)
- Dimas G de Oteyza
- Nanomaterials and Nanotechnology Research Center (CINN), CSIC-UNIOVI-PA, E-33940 El Entrego, Spain
- Donostia International Physics Center (DIPC)-UPV/EHU, E-20018 San Sebastián, Spain
| | - Thomas Frederiksen
- Donostia International Physics Center (DIPC)-UPV/EHU, E-20018 San Sebastián, Spain
- Ikerbasque, Basque Foundation for Science, E-48013 Bilbao, Spain
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Lu J, Jiang H, Yan Y, Zhu Z, Zheng F, Sun Q. High-Throughput Preparation of Supramolecular Nanostructures on Metal Surfaces. ACS NANO 2022; 16:13160-13167. [PMID: 35862580 DOI: 10.1021/acsnano.2c06294] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
One of the contemporary challenges in materials science lies in the rapid materials screening and discovery. Experimental sample libraries can be generated by high-throughput parallel synthesis to map the composition space for rapid material discoveries. Molecular self-assembly on surfaces has proved a useful way to construct nanostructures with interesting topologies or properties. Despite the strong dependence of molecular stoichiometry on the structures, high-throughput preparations of supramolecular surface nanostructures have been far less explored. Here, by integrating a physical mask into the standard ultra-high-vacuum (UHV) molecular preparation system we show a high-throughput approach for preparing supramolecular nanostructures of continuous composition spreads on metal surfaces. The spatially addressable sample libraries of supramolecular self-assemblies are characterized by high-resolution scanning probe microscopy. We could explore different binary nanostructures of varying molecular ratios on one single substrate. Moreover, we use the minimum spanning tree approach to qualitatively and quantitatively study the structural properties of the formed nanostructures. This high-throughput approach may accelerate the screening and exploration of surface-supported, low-dimensional nanostructures not limited to supramolecular interactions.
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Affiliation(s)
- Jiayi Lu
- Materials Genome Institute, Shanghai University, 200444 Shanghai, China
| | - Hao Jiang
- Materials Genome Institute, Shanghai University, 200444 Shanghai, China
| | - Yuyi Yan
- Materials Genome Institute, Shanghai University, 200444 Shanghai, China
| | - Zhiwen Zhu
- Materials Genome Institute, Shanghai University, 200444 Shanghai, China
| | - Fengru Zheng
- Materials Genome Institute, Shanghai University, 200444 Shanghai, China
| | - Qiang Sun
- Materials Genome Institute, Shanghai University, 200444 Shanghai, China
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