1
|
Ooe H, Yokoyama T. On-surface polymerization reactions of dibrominated hexaphenylbenzene influenced by densely packed self-assembly. Phys Chem Chem Phys 2024; 26:12939-12946. [PMID: 38629232 DOI: 10.1039/d4cp00696h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/02/2024]
Abstract
Controlled bottom-up fabrication of molecular nanostructures through on-surface reactions of tailor-made precursors is of scientific and technological interest. Recently, on-surface polymerization reactions influenced by precursor self-assembly have been reported. Thus, a fundamental understanding of the reaction process is a prerequisite for controlled formation. Herein, we report on the influence of molecular self-assembly of dibrominated hexaphenylbenzene (Br2-HPB) on the on-surface polymerization reactions on a Au(111) substrate. By using low-temperature scanning tunnelling microscopy (STM), we find that the polymerization of Br2-HPB proceeds while maintaining the long-range ordered self-assembly, despite a decrease in HPB-HPB distance due to debromination and successive covalent bonding of Br2-HPB. From the STM investigations of the polymerization process, we conclude that the polymerization of Br2-HPB is accompanied by molecular rotations to maintain the periodic array of the self-assembled structure, contrary to the conventional understanding of the polymerization of the self-assembled precursor layer.
Collapse
Affiliation(s)
- Hiroaki Ooe
- Faculty of Science, Yokohama City University, 22-2 Seto, Kanazawa-ku, Yokohama 236-0027, Japan.
| | - Takashi Yokoyama
- Faculty of Science, Yokohama City University, 22-2 Seto, Kanazawa-ku, Yokohama 236-0027, Japan.
| |
Collapse
|
2
|
Kinikar A, Wang XY, Di Giovannantonio M, Urgel JI, Liu P, Eimre K, Pignedoli CA, Stolz S, Bommert M, Mishra S, Sun Q, Widmer R, Qiu Z, Narita A, Müllen K, Ruffieux P, Fasel R. Sterically Selective [3 + 3] Cycloaromatization in the On-Surface Synthesis of Nanographenes. ACS NANOSCIENCE AU 2024; 4:128-135. [PMID: 38644965 PMCID: PMC11027121 DOI: 10.1021/acsnanoscienceau.3c00062] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/06/2023] [Revised: 12/14/2023] [Accepted: 12/15/2023] [Indexed: 04/23/2024]
Abstract
Surface-catalyzed reactions have been used to synthesize carbon nanomaterials with atomically predefined structures. The recent discovery of a gold surface-catalyzed [3 + 3] cycloaromatization of isopropyl substituted arenes has enabled the on-surface synthesis of arylene-phenylene copolymers, where the surface activates the isopropyl substituents to form phenylene rings by intermolecular coupling. However, the resulting polymers suffered from undesired cross-linking when more than two molecules reacted at a single site. Here we show that such cross-links can be prevented through steric protection by attaching the isopropyl groups to larger arene cores. Upon thermal activation of isopropyl-substituted 8,9-dioxa-8a-borabenzo[fg]tetracene on Au(111), cycloaromatization is observed to occur exclusively between the two molecules. The cycloaromatization intermediate formed by the covalent linking of two molecules is prevented from reacting with further molecules by the wide benzotetracene core, resulting in highly selective one-to-one coupling. Our findings extend the versatility of the [3 + 3] cycloaromatization of isopropyl substituents and point toward steric protection as a powerful concept for suppressing competing reaction pathways in on-surface synthesis.
Collapse
Affiliation(s)
- Amogh Kinikar
- Empa, Swiss
Federal Laboratories for Materials Science and Technology, 8600 Dübendorf, Switzerland
| | - Xiao-Ye Wang
- Max Planck
Institute for Polymer Research, 55128 Mainz, Germany
- State
Key
Laboratory of Elemento-Organic Chemistry, College of Chemistry, Nankai University, Tianjin 300071, China
| | - Marco Di Giovannantonio
- Empa, Swiss
Federal Laboratories for Materials Science and Technology, 8600 Dübendorf, Switzerland
| | - José I. Urgel
- Empa, Swiss
Federal Laboratories for Materials Science and Technology, 8600 Dübendorf, Switzerland
| | - Pengcai Liu
- State
Key
Laboratory of Elemento-Organic Chemistry, College of Chemistry, Nankai University, Tianjin 300071, China
| | - Kristjan Eimre
- Empa, Swiss
Federal Laboratories for Materials Science and Technology, 8600 Dübendorf, Switzerland
| | - Carlo A. Pignedoli
- Empa, Swiss
Federal Laboratories for Materials Science and Technology, 8600 Dübendorf, Switzerland
| | - Samuel Stolz
- Empa, Swiss
Federal Laboratories for Materials Science and Technology, 8600 Dübendorf, Switzerland
- Institute
of Condensed Matter Physics, Station 3, EPFL, 1015 Lausanne, Switzerland
| | - Max Bommert
- Empa, Swiss
Federal Laboratories for Materials Science and Technology, 8600 Dübendorf, Switzerland
| | - Shantanu Mishra
- Empa, Swiss
Federal Laboratories for Materials Science and Technology, 8600 Dübendorf, Switzerland
| | - Qiang Sun
- Empa, Swiss
Federal Laboratories for Materials Science and Technology, 8600 Dübendorf, Switzerland
| | - Roland Widmer
- Empa, Swiss
Federal Laboratories for Materials Science and Technology, 8600 Dübendorf, Switzerland
| | - Zijie Qiu
- Max Planck
Institute for Polymer Research, 55128 Mainz, Germany
| | - Akimitsu Narita
- Max Planck
Institute for Polymer Research, 55128 Mainz, Germany
| | - Klaus Müllen
- Max Planck
Institute for Polymer Research, 55128 Mainz, Germany
- Department
of Chemistry, Johannes Gutenberg-Universität
Mainz, 55128 Mainz, Germany
| | - Pascal Ruffieux
- Empa, Swiss
Federal Laboratories for Materials Science and Technology, 8600 Dübendorf, Switzerland
| | - Roman Fasel
- Empa, Swiss
Federal Laboratories for Materials Science and Technology, 8600 Dübendorf, Switzerland
- Department
of Chemistry, Biochemistry and Pharmaceutical Sciences, University of Bern, 3012 Bern, Switzerland
| |
Collapse
|
3
|
Fu B, Lu J, Geng J, Zhang Y, Sun S, Xiong W, Zhang Y, Niu G, Gao L, Cai J. On-surface synthesis of two types of cyano-substituted polyfluorene derivatives via Ullmann coupling on Au(111). NANOSCALE 2024. [PMID: 38436109 DOI: 10.1039/d3nr06186h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/05/2024]
Abstract
Using 4-(3,6-dibromo-9H-carbazol-9-yl)benzonitrile (DBCB) precursors, we successfully constructed two types of cyano-substituted polymers on Au(111) by the molecular beam epitaxy method. According to the geometry, the two polymers are referred to as w-type polymers composed of cis-dimers and z-type polymers composed of trans-dimers. The intermediate dimers and final polymers were well characterized by high-resolution scanning tunneling microscopy (HR-STM). Moreover, the productivities of these two polymers can be controlled by adjusting the heating rate and different treatment methods. High heating rates and hot deposition can provide more ample space and time for molecular diffusion, which is conducive to the formation of w-type polymers with relatively low density. In addition, by combining scanning tunneling spectroscopy (STS) and density functional theory (DFT) calculations, we have shown that the addition of CN groups reduces the band gap of the two polymers. Our investigation thus shows the controllable construction of nanostructures through efficient surface synthesis parameters and reveals the potential of using functional groups as tools to modify the electronic properties of polymers.
Collapse
Affiliation(s)
- Boyu Fu
- Faculty of Materials Science and Engineering, Kunming University of Science and Technology, No. 68 Wenchang Road, Kunming 650093, China.
| | - Jianchen Lu
- Faculty of Materials Science and Engineering, Kunming University of Science and Technology, No. 68 Wenchang Road, Kunming 650093, China.
| | - Jianqun Geng
- Faculty of Materials Science and Engineering, Kunming University of Science and Technology, No. 68 Wenchang Road, Kunming 650093, China.
| | - Yong Zhang
- Faculty of Materials Science and Engineering, Kunming University of Science and Technology, No. 68 Wenchang Road, Kunming 650093, China.
| | - Shijie Sun
- Faculty of Materials Science and Engineering, Kunming University of Science and Technology, No. 68 Wenchang Road, Kunming 650093, China.
| | - Wei Xiong
- Faculty of Materials Science and Engineering, Kunming University of Science and Technology, No. 68 Wenchang Road, Kunming 650093, China.
| | - Yi Zhang
- Faculty of Materials Science and Engineering, Kunming University of Science and Technology, No. 68 Wenchang Road, Kunming 650093, China.
| | - Gefei Niu
- Faculty of Materials Science and Engineering, Kunming University of Science and Technology, No. 68 Wenchang Road, Kunming 650093, China.
| | - Lei Gao
- Faculty of Science, Kunming University of Science and Technology, No. 727 Jingming South Road, Kunming 650500, China.
| | - Jinming Cai
- Faculty of Materials Science and Engineering, Kunming University of Science and Technology, No. 68 Wenchang Road, Kunming 650093, China.
- Southwest United Graduate School, Kunming, 650000, China
| |
Collapse
|
4
|
Xu X, Kinikar A, Di Giovannantonio M, Pignedoli CA, Ruffieux P, Müllen K, Fasel R, Narita A. On-Surface Synthesis of Anthracene-Fused Zigzag Graphene Nanoribbons from 2,7-Dibromo-9,9'-bianthryl Reveals Unexpected Ring Rearrangements. PRECISION CHEMISTRY 2024; 2:81-87. [PMID: 38425747 PMCID: PMC10900509 DOI: 10.1021/prechem.3c00116] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/06/2023] [Revised: 01/17/2024] [Accepted: 01/22/2024] [Indexed: 03/02/2024]
Abstract
On-surface synthesis has emerged as a powerful strategy to fabricate unprecedented forms of atomically precise graphene nanoribbons (GNRs). However, the on-surface synthesis of zigzag GNRs (ZGNR) has met with only limited success. Herein, we report the synthesis and on-surface reactions of 2,7-dibromo-9,9'-bianthryl as the precursor toward π-extended ZGNRs. Characterization by scanning tunneling microscopy and high-resolution noncontact atomic force microscopy clearly demonstrated the formation of anthracene-fused ZGNRs. Unique skeletal rearrangements were also observed, which could be explained by intramolecular Diels-Alder cycloaddition. Theoretical calculations of the electronic properties of the anthracene-fused ZGNRs revealed spin-polarized edge-states and a narrow bandgap of 0.20 eV.
Collapse
Affiliation(s)
- Xiushang Xu
- Max
Planck Institute for Polymer Research, 55128 Mainz, Germany
- Organic
and Carbon Nanomaterials Unit, Okinawa Institute
of Science and Technology Graduate University, 1919-1 Tancha, Onna-son, Kunigami-gun, Okinawa 904-0495, Japan
| | - Amogh Kinikar
- Empa,
Swiss Federal Laboratories for Materials Science and Technology, nanotech@surfaces
Laboratory, 8600 Dübendorf, Switzerland
| | - Marco Di Giovannantonio
- Empa,
Swiss Federal Laboratories for Materials Science and Technology, nanotech@surfaces
Laboratory, 8600 Dübendorf, Switzerland
- Institute
of Structure of Matter − CNR (ISM-CNR), via Fosso del Cavaliere 100, 00133 Roma, Italy
| | | | - Pascal Ruffieux
- Empa,
Swiss Federal Laboratories for Materials Science and Technology, nanotech@surfaces
Laboratory, 8600 Dübendorf, Switzerland
| | - Klaus Müllen
- Max
Planck Institute for Polymer Research, 55128 Mainz, Germany
- Institute
of Physical Chemistry, Johannes Gutenberg
University Mainz, Duesbergweg
10-14, 55128 Mainz, Germany
| | - Roman Fasel
- Empa,
Swiss Federal Laboratories for Materials Science and Technology, nanotech@surfaces
Laboratory, 8600 Dübendorf, Switzerland
- Department
of Chemistry, Biochemistry and Pharmaceutical Sciences, University of Bern, Freiestrasse 3, 3012 Bern, Switzerland
| | - Akimitsu Narita
- Max
Planck Institute for Polymer Research, 55128 Mainz, Germany
- Organic
and Carbon Nanomaterials Unit, Okinawa Institute
of Science and Technology Graduate University, 1919-1 Tancha, Onna-son, Kunigami-gun, Okinawa 904-0495, Japan
| |
Collapse
|
5
|
Zhao C, Bhagwandin DD, Xu W, Ruffieux P, Khan SI, Pignedoli CA, Fasel R, Rubin Y. Dramatic Acceleration of the Hopf Cyclization on Gold(111): From Enediynes to Peri-Fused Diindenochrysene Graphene Nanoribbons. J Am Chem Soc 2024; 146:2474-2483. [PMID: 38227949 PMCID: PMC10835731 DOI: 10.1021/jacs.3c10144] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2024]
Abstract
Hopf et al. reported the high-temperature 6π-electrocyclization of cis-hexa-1,3-diene-5-yne to benzene in 1969. Subsequent studies using this cyclization have been limited by its very high reaction barrier. Here, we show that the reaction barrier for two model systems, (E)-1,3,4,6-tetraphenyl-3-hexene-1,5-diyne (1a) and (E)-3,4-bis(4-iodophenyl)-1,6-diphenyl-3-hexene-1,5-diyne (1b), is decreased by nearly half on a Au(111) surface. We have used scanning tunneling microscopy (STM) and noncontact atomic force microscopy (nc-AFM) to monitor the Hopf cyclization of enediynes 1a,b on Au(111). Enediyne 1a undergoes two sequential, quantitative Hopf cyclizations, first to naphthalene derivative 2, and finally to chrysene 3. Density functional theory (DFT) calculations reveal that a gold atom from the Au(111) surface is involved in all steps of this reaction and that it is crucial to lowering the reaction barrier. Our findings have important implications for the synthesis of novel graphene nanoribbons. Ullmann-like coupling of enediyne 1b at 20 °C on Au(111), followed by a series of Hopf cyclizations and aromatization reactions at higher temperatures, produces nanoribbons 12 and 13. These results show for the first time that graphene nanoribbons can be synthesized on a Au(111) surface using the Hopf cyclization mechanism.
Collapse
Affiliation(s)
- Chenxiao Zhao
- Nanotech@surfaces Laboratory, Empa-Swiss Federal Laboratories for Materials Science and Technology, 8600 Dübendorf, Switzerland
| | - Dayanni D Bhagwandin
- Department of Chemistry and Biochemistry, University of California, Los Angeles, 607 Charles Young Dr. East, Los Angeles, California 90095-1567, United States
| | - Wangwei Xu
- Nanotech@surfaces Laboratory, Empa-Swiss Federal Laboratories for Materials Science and Technology, 8600 Dübendorf, Switzerland
- Department of Chemistry, Biochemistry and Pharmaceutical Sciences, University of Bern, 3012 Bern, Switzerland
| | - Pascal Ruffieux
- Nanotech@surfaces Laboratory, Empa-Swiss Federal Laboratories for Materials Science and Technology, 8600 Dübendorf, Switzerland
| | - Saeed I Khan
- Department of Chemistry and Biochemistry, University of California, Los Angeles, 607 Charles Young Dr. East, Los Angeles, California 90095-1567, United States
| | - Carlo A Pignedoli
- Nanotech@surfaces Laboratory, Empa-Swiss Federal Laboratories for Materials Science and Technology, 8600 Dübendorf, Switzerland
| | - Roman Fasel
- Nanotech@surfaces Laboratory, Empa-Swiss Federal Laboratories for Materials Science and Technology, 8600 Dübendorf, Switzerland
- Department of Chemistry, Biochemistry and Pharmaceutical Sciences, University of Bern, 3012 Bern, Switzerland
| | - Yves Rubin
- Department of Chemistry and Biochemistry, University of California, Los Angeles, 607 Charles Young Dr. East, Los Angeles, California 90095-1567, United States
| |
Collapse
|