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Takahashi S, Sekiya R, Haino T. Computational Studies on the Structures of Nanographenes with Various Edge Functionalities. Chemphyschem 2023; 24:e202200465. [PMID: 36377417 DOI: 10.1002/cphc.202200465] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2022] [Revised: 11/12/2022] [Indexed: 11/16/2022]
Abstract
Computational studies have often been carried out on hydrogen-terminated nanographenes (NGs). These structures are, however, far from those deduced from experimental observations, which have suggested armchair edges with two carboxy groups on the edges as dominant. We conducted computational studies on NGs consisting of C42 , C60 , C78 , C96 , C142 , and C174 carbon atoms with hydrogen, carboxy, and N-methyl imide-terminated armchair edges. DFT calculations inform distorted basal planes and similar HOMO-LUMO gaps, indicating that the edge oxidation and functionalization do not very influence the electronic structure. Comparison of observed UV-vis spectra of carboxy- and N-octadecyl chain terminated NGs with calculated spectra of model NGs informs the contribution of π-π* transitions on the basal plane to the absorptions in the visible region. A dimeric structure of NG and octadecyl-installed NG demonstrate that both the distorted basal planes and the steric contacts among the functional groups widen the surface-to-surface distance thereby allowing the invasion of solvent molecules between the surfaces. This picture is consistent with the improved solubility of edge-modified NGs.
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Affiliation(s)
- Shusaku Takahashi
- Department of Chemistry, Graduate School of Advanced Science and Engineering, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima, Hiroshima, 739-8526, Japan
| | - Ryo Sekiya
- Department of Chemistry, Graduate School of Advanced Science and Engineering, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima, Hiroshima, 739-8526, Japan
| | - Takeharu Haino
- Department of Chemistry, Graduate School of Advanced Science and Engineering, Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima, Hiroshima, 739-8526, Japan.,International Institute for Sustainability with Knotted Chiral Meta Matter (SKCM2), Hiroshima University, 1-3-1 Kagamiyama, Higashi-Hiroshima, Hiroshima, 739-8526, Japan
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Abstract
Despite its great explanatory power in understanding the chemistry of polycyclic aromatic hydrocarbons (PAHs) and related systems, the Clar sextet rule still remains an intuitive and qualitative model with notable exceptions in some cases. Here we develop a quantitative theory of chemical resonance based on semilocalized Clar-type resonance structures (named the Clar resonators) consisting of variable numbers of Clar sextets and C═C bonds. The constructed wave functions of the Clar resonators are used to expand the actual wave function of the π-conjugated system obtained from a DFT or Hartree-Fock calculation. The resultant weights and one-electron energies of the Clar resonators can serve as a quantitative measure of the importance of these resonators. Implementing the theory in our open-source python code EzReson and applying it to over a thousand PAH molecules of different sizes and shapes, we show that the weight of the Clar resonators increases exponentially with increasing number of sextets and that their energy decreases linearly with the latter, thus confirming the general validity of the Clar rule. On the basis of such a large-scale resonance analysis, we propose three extended Clar rules, along with a unified quantitative model, that are able to evaluate the importance of all Clar resonators and the ring aromaticity for PAHs. Using the present theories, we uncover the essential role that the minor Clar resonators may play in correctly understanding the resonance stabilization and local aromaticity of rings, which was totally overlooked in the original Clar model.
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Affiliation(s)
- Yang Wang
- School of Chemistry and Chemical Engineering, Yangzhou University, Yangzhou, Jiangsu 225002, China
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3
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Abstract
Buckybowls have concave and convex surfaces with distinct π-electron cloud distribution, and consequently they show unique structural and electronic features as compared to planar aromatic polycycles. Doping the π-framework of buckybowls with heteroatoms is an efficient scheme to tailor inherent properties, because the nature of heteroatoms plays a pivotal role in the structural and electronic characteristics of the resulting hetera-buckybowls. The design, synthesis, and derivatization of hetera-buckybowls open an avenue for obtaining fascinating organic entities not only of fundamental importance but also of promising applications in optoelectronics. In this review, we summarize the advances in hetera-buckybowl chemistry, particularly the synthetic strategies toward these scaffolds.
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Affiliation(s)
- Wenbo Wang
- State Key Laboratory of Applied Organic Chemistry, Lanzhou University, Lanzhou 730000, Gansu Province, China.
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Monaco G, Scott ELT, Zanasi R. Reversal of Clar's Aromatic-Sextet Rule in Ultrashort Single-End-Capped [5,5] Carbon Nanotubes. ChemistryOpen 2020; 9:616-622. [PMID: 32489766 PMCID: PMC7253069 DOI: 10.1002/open.202000091] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2020] [Revised: 05/06/2020] [Indexed: 12/18/2022] Open
Abstract
The three-fold HOMO-LUMO gap oscillation, typical of finite length armchair carbon nanotubes (CNT), has a major effect on the magnetic response of ultrashort, single-end-capped [5,5] carbon nanotubes to a perturbing magnetic field parallel to the main symmetry axis. For the CNT's containing 40, 70, and 100 carbon atoms, for which 100 % of the C=C double bonds can be grouped into aromatic-sextets, i. e., fully or complete Clar networks, large paratropic (antiaromatic) global circulations around the cylindrical axis are predicted at the DFT level of calculation. Local and semi-global diatropic (aromatic) currents of strengths not larger than that of the benzene molecule are determined for a perpendicular perturbing magnetic field. CNTs of intermediate lengths do not display this enhanced antiaromatic response. The paratropic current flow clearly shows that these complete Clar networks can be viewed as stacked cycloparaphenylene belts, each providing a double 4 n annulene circuit as a consequence of the quinoidal resonance structure that results from their closure. Paradoxically, the fully aromatic Clar structure itself is responsible for the enhanced global antiaromaticity.
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Affiliation(s)
- Guglielmo Monaco
- Dipartimento di Chimica e Biologia “A. Zambelli”Università degli studi di Salernovia Giovanni Paolo II 132Fisciano84084SAItaly
| | | | - Riccardo Zanasi
- Dipartimento di Chimica e Biologia “A. Zambelli”Università degli studi di Salernovia Giovanni Paolo II 132Fisciano84084SAItaly
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Schaub TA, Padberg K, Kivala M. Bridged triarylboranes, ‐silanes, ‐amines, and ‐phosphines as minimalistic heteroatom‐containing polycyclic aromatic hydrocarbons: Progress and challenges. J PHYS ORG CHEM 2019. [DOI: 10.1002/poc.4022] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Affiliation(s)
- Tobias A. Schaub
- Organisch‐Chemisches InstitutRuprecht‐Karls‐Universität Heidelberg Heidelberg Germany
| | - Kevin Padberg
- Department of Chemistry and PharmacyUniversität Erlangen‐Nürnberg Erlangen Germany
| | - Milan Kivala
- Organisch‐Chemisches InstitutRuprecht‐Karls‐Universität Heidelberg Heidelberg Germany
- Centre for Advanced MaterialsRuprecht‐Karls‐Universität Heidelberg Heidelberg Germany
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6
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How much aromatic are naphthalene and graphene? COMPUT THEOR CHEM 2019. [DOI: 10.1016/j.comptc.2019.112504] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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7
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Dias JR. Edge Effects in Benzenoid and Total Resonant Sextet Benzenoid Hydrocarbons and Clar’s Sextet Principle. J Phys Chem A 2019; 123:3229-3238. [DOI: 10.1021/acs.jpca.9b01356] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Jerry Ray Dias
- Department of Chemistry, University of Missouri, Kansas City, Kansas City, Missouri 64110-2499, United States
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Aihara JI. Graph Theory of Ring-Current Diamagnetism. BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 2018. [DOI: 10.1246/bcsj.20170318] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Jun-ichi Aihara
- Department of Chemistry, Faculty of Science, Shizuoka University, Oya, Shizuoka 422-8529
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Makino M, Nishina N, Aihara JI. Critical evaluation of HOMA and MBL as local aromaticity indices. J PHYS ORG CHEM 2017. [DOI: 10.1002/poc.3783] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
- Masakazu Makino
- Department of Environmental and Life Sciences, School of Food and Nutritional Sciences; University of Shizuoka; Shizuoka Japan
| | - Naoko Nishina
- Department of Chemistry, Faculty of Science; Shizuoka University; Shizuoka Japan
| | - Jun-ichi Aihara
- Department of Environmental and Life Sciences, School of Food and Nutritional Sciences; University of Shizuoka; Shizuoka Japan
- Department of Chemistry, Faculty of Science; Shizuoka University; Shizuoka Japan
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Aihara JI. Graph Theory of Aromatic Stabilization. BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 2016. [DOI: 10.1246/bcsj.20160237] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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Setiawan D, Kraka E, Cremer D. Quantitative Assessment of Aromaticity and Antiaromaticity Utilizing Vibrational Spectroscopy. J Org Chem 2016; 81:9669-9686. [DOI: 10.1021/acs.joc.6b01761] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Dani Setiawan
- Computational and Theoretical
Chemistry Group (CATCO), Department of Chemistry, Southern Methodist University, 3215 Daniel Ave., Dallas, Texas 75275-0314, United States
| | - Elfi Kraka
- Computational and Theoretical
Chemistry Group (CATCO), Department of Chemistry, Southern Methodist University, 3215 Daniel Ave., Dallas, Texas 75275-0314, United States
| | - Dieter Cremer
- Computational and Theoretical
Chemistry Group (CATCO), Department of Chemistry, Southern Methodist University, 3215 Daniel Ave., Dallas, Texas 75275-0314, United States
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Otero N, El-kelany KE, Pouchan C, Rérat M, Karamanis P. Establishing the pivotal role of local aromaticity in the electronic properties of boron-nitride graphene lateral hybrids. Phys Chem Chem Phys 2016; 18:25315-25328. [PMID: 27711641 DOI: 10.1039/c6cp04502b] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Within an attempt to unravel the conundrum of irregular bandgap variations in hybrids of white-graphene (hBN) and graphene (G) observed in both experiment and theory, strong proofs about the decisive role of aromaticity in their electronic properties are brought to light.
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Affiliation(s)
- Nicolás Otero
- Equipe de Chimie Théorique
- ECP Institut des Sciences Analytiques et de Physico-chimie pour l'Environnement et les Matériaux (IPREM) UMR 5254. Hélioparc Pau Pyrénées 2 avenue du Président Angot
- 64053 PAU Cedex 09
- France
- Departamento de Química Física
| | - Khaled E. El-kelany
- Equipe de Chimie Théorique
- ECP Institut des Sciences Analytiques et de Physico-chimie pour l'Environnement et les Matériaux (IPREM) UMR 5254. Hélioparc Pau Pyrénées 2 avenue du Président Angot
- 64053 PAU Cedex 09
- France
- CompChem Lab
| | - Claude Pouchan
- Equipe de Chimie Théorique
- ECP Institut des Sciences Analytiques et de Physico-chimie pour l'Environnement et les Matériaux (IPREM) UMR 5254. Hélioparc Pau Pyrénées 2 avenue du Président Angot
- 64053 PAU Cedex 09
- France
| | - Michel Rérat
- Equipe de Chimie Théorique
- ECP Institut des Sciences Analytiques et de Physico-chimie pour l'Environnement et les Matériaux (IPREM) UMR 5254. Hélioparc Pau Pyrénées 2 avenue du Président Angot
- 64053 PAU Cedex 09
- France
| | - Panaghiotis Karamanis
- Equipe de Chimie Théorique
- ECP Institut des Sciences Analytiques et de Physico-chimie pour l'Environnement et les Matériaux (IPREM) UMR 5254. Hélioparc Pau Pyrénées 2 avenue du Président Angot
- 64053 PAU Cedex 09
- France
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