1
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Chagas JCV, Milanez BD, Oliveira VP, Pinheiro M, Ferrão LFA, Aquino AJA, Lischka H, Machado FBC. A multi-descriptor analysis of substituent effects on the structure and aromaticity of benzene derivatives: π-Conjugation versus charge effects. J Comput Chem 2024; 45:863-877. [PMID: 38153839 DOI: 10.1002/jcc.27296] [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: 08/24/2023] [Revised: 11/29/2023] [Accepted: 12/10/2023] [Indexed: 12/30/2023]
Abstract
This work provides a detailed multi-component analysis of aromaticity in monosubstituted (X = CH3, CH 2 - , CH 2 + , NH2, NH-, NH+, OH, O-, and O+) and para-homodisubstituted (X = CH3, CH2, NH2, NH, OH, and O) benzene derivatives. We investigate the effects of substituents using single-reference (B3LYP/DFT) and multireference (CASSCF/MRCI) methods, focusing on structural (HOMA), vibrational (AI(vib)), topological (ELFπ), electronic (MCI), magnetic (NICS), and stability (S0-T1 splitting) properties. The findings reveal that appropriate π-electron-donating and π-electron-accepting substituents with suitable size and symmetry can interact with the π-system of the ring, significantly influencing π-electron delocalization. While the charge factor has a minimal impact on π-electron delocalization, the presence of a pz orbital capable of interacting with the π-electron delocalization is the primary factor leading to a deviation from the typical aromaticity characteristics observed in benzene.
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Affiliation(s)
- Julio C V Chagas
- Department of Chemistry, Aeronautics Institute of Technology, São José dos Campos, São Paulo, Brazil
| | - Bruno D Milanez
- Department of Chemistry, Aeronautics Institute of Technology, São José dos Campos, São Paulo, Brazil
| | - Vytor P Oliveira
- Department of Chemistry, Aeronautics Institute of Technology, São José dos Campos, São Paulo, Brazil
| | - Max Pinheiro
- Department of Chemistry, Aeronautics Institute of Technology, São José dos Campos, São Paulo, Brazil
| | - Luiz F A Ferrão
- Department of Chemistry, Aeronautics Institute of Technology, São José dos Campos, São Paulo, Brazil
| | - Adelia J A Aquino
- Department of Mechanical Engineering, Texas Tech University, Lubbock, Texas, USA
| | - Hans Lischka
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, Texas, USA
| | - Francisco B C Machado
- Department of Chemistry, Aeronautics Institute of Technology, São José dos Campos, São Paulo, Brazil
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2
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Ding B, Bhosale M, Bennett TLR, Heeney M, Plasser F, Esser B, Glöcklhofer F. Reducing undesired solubility of squarephaneic tetraimide for use as an organic battery electrode material. Faraday Discuss 2024; 250:129-144. [PMID: 37965707 PMCID: PMC10926975 DOI: 10.1039/d3fd00145h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2023] [Accepted: 08/17/2023] [Indexed: 11/16/2023]
Abstract
Locally aromatic alkyl-N-substituted squarephaneic tetraimide (SqTI) conjugated macrocycles are four-electron reducible, owing to global aromaticity and presumed global Baird aromaticity of the dianion and tetraanion states, respectively. However, their good solubility inhibits their application as a battery electrode material. By applying sidechain removal as a strategy to reduce SqTI solubility, we report the development of its unsubstituted derivative SqTI-H, which was obtained directly from squarephaneic tetraanhydride by facile treatment with hexamethyldisilazane and MeOH. Compared to alkyl-N-substituted SqTI-Rs, SqTI-H exhibited further improved thermal stability and low neutral state solubility in most common organic solvents, owing to computationally demonstrated hydrogen-bonding capabilities emanating from each imide position on SqTI-H. Reversible solid state electrochemical reduction of SqTI-H to the globally aromatic dianion state was also observed at -1.25 V vs. Fc/Fc+, which could be further reduced in two stages. Preliminary testing of SqTI-H in composite electrodes for lithium-organic half cells uncovered imperfect cycling performance, which may be explained by persistent solubility of reduced states, necessitating further optimisation of electrode fabrication procedures to attain maximum performance.
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Affiliation(s)
- Bowen Ding
- Department of Chemistry and Centre for Processable Electronics, Imperial College London, Molecular Sciences Research Hub (White City Campus), 80 Wood Lane Shepherd's Bush, London W12 0BZ, UK.
| | - Manik Bhosale
- Institute of Organic Chemistry II and Advanced Materials, Ulm University, Albert-Einstein-Allee 11, 89081 Ulm, Germany.
| | - Troy L R Bennett
- Department of Chemistry and Centre for Processable Electronics, Imperial College London, Molecular Sciences Research Hub (White City Campus), 80 Wood Lane Shepherd's Bush, London W12 0BZ, UK.
| | - Martin Heeney
- Department of Chemistry and Centre for Processable Electronics, Imperial College London, Molecular Sciences Research Hub (White City Campus), 80 Wood Lane Shepherd's Bush, London W12 0BZ, UK.
- Physical Sciences and Engineering Division (PSE), King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900, Saudi Arabia
| | - Felix Plasser
- Department of Chemistry, Loughborough University, Loughborough LE11 3TU, UK
| | - Birgit Esser
- Institute of Organic Chemistry II and Advanced Materials, Ulm University, Albert-Einstein-Allee 11, 89081 Ulm, Germany.
| | - Florian Glöcklhofer
- Department of Chemistry and Centre for Processable Electronics, Imperial College London, Molecular Sciences Research Hub (White City Campus), 80 Wood Lane Shepherd's Bush, London W12 0BZ, UK.
- Institute of Applied Synthetic Chemistry, TU Wien, Getreidemarkt 9/163, 1060 Vienna, Austria.
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3
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Stawski W, Zhu Y, Wei Z, Petrukhina MA, Anderson HL. Crystallographic evidence for global aromaticity in the di-anion and tetra-anion of a cyclophane hydrocarbon. Chem Sci 2023; 14:14109-14114. [PMID: 38098717 PMCID: PMC10718070 DOI: 10.1039/d3sc04251k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2023] [Accepted: 09/20/2023] [Indexed: 12/17/2023] Open
Abstract
[24]Paracyclophanetetraene is a classic example of a macrocyclic hydrocarbon that becomes globally aromatic on reduction to the di-anion, and switches to globally anti-aromatic in the tetra-anion. This redox activity makes it promising as an electrode material for batteries. Here, we report the solid-state structures of the di- and tetra-anions of this cyclophane, in several coordination environments. The changes in bond length on reduction yield insights into the global aromaticity of the di-anion (26π electrons), and anti-aromaticity of the tetra-anion (28π electrons), that were previously deduced from NMR spectra of species generated in situ. The experimental geometries of the aromatic di-anion and anti-aromatic tetra-anion from X-ray crystallographic data match well with gas-phase calculated structures, and reproduce the low symmetry expected in the anti-aromatic ring. Comparison of coordinated and naked anions confirms that metal coordination has little effect on the bond lengths. The UV-vis-NIR absorption spectra show a sharp intense peak at 878 nm for the di-anion, whereas the tetra-anion gives a broad spectrum typical of an anti-aromatic system.
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Affiliation(s)
- Wojciech Stawski
- Department of Chemistry, University at Albany, State University of New York Albany NY 12222 USA
- Department of Chemistry, University of Oxford, Chemistry Research Laboratory Oxford OX1 3TA UK
| | - Yikun Zhu
- Department of Chemistry, University at Albany, State University of New York Albany NY 12222 USA
| | - Zheng Wei
- Department of Chemistry, University at Albany, State University of New York Albany NY 12222 USA
| | - Marina A Petrukhina
- Department of Chemistry, University at Albany, State University of New York Albany NY 12222 USA
| | - Harry L Anderson
- Department of Chemistry, University of Oxford, Chemistry Research Laboratory Oxford OX1 3TA UK
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4
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Ferrão LFA, Pontes MAP, Fernandes GFS, Bettanin F, Aquino AJA, Lischka H, Nachtigallova D, Machado FBC. Stability and Reactivity of the Phenalene and Olympicene Isomers. J Phys Chem A 2023; 127:9430-9441. [PMID: 37920974 DOI: 10.1021/acs.jpca.3c04331] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2023]
Abstract
The phenalene (triangulene) and olympicene molecules belong to the polycyclic aromatic hydrocarbon class, which have attracted substantial technological interest due to their unique electronic properties. Electronic structure calculations serve as a valuable tool in investigating the stability and reactivity of these molecular systems. In the present work, the multireference calculations, namely, the complete active space second-order perturbation theory and multireference averaged quadratic coupled cluster (MR-AQCC), were employed to study the reactivity and stability of phenalene and olympicene isomers, as well as their modified structures where the sp3-carbon at the borders were removed. The harmonic oscillator model of aromaticity (HOMA) and the nucleus-independent chemical shift as geometric and magnetic indexes calculated with density functional theory were utilized to assess the aromaticity of the studied molecules. These indexes were compared with properties such as the excitation energy and natural orbitals occupation. The reactivity analyzed using the HOMA index combined with MR-AQCC revealed the radical character of certain structures as well as the weakening of their aromaticity. Moreover, the results suggest that the removal of sp3-carbon atoms and the addition of hydrogen atoms did not alter the π network and the excitation energies of the phenalene molecules.
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Affiliation(s)
- Luiz F A Ferrão
- Departamento de Química, Instituto Tecnológico de Aeronáutica, São José dos Campos 122228-900, SP, Brazil
| | - Marcelo A P Pontes
- Departamento de Química, Instituto Tecnológico de Aeronáutica, São José dos Campos 122228-900, SP, Brazil
| | - Gabriel F S Fernandes
- Departamento de Química, Instituto Tecnológico de Aeronáutica, São José dos Campos 122228-900, SP, Brazil
| | - Fernanda Bettanin
- Escola de Artes, Ciências e Humanidades (EACH) - Universidade de São Paulo (USP), São Paulo 03828-000, SP, Brazil
| | - Adélia J A Aquino
- Department of Mechanical Engineering, Texas Tech University, Lubbock, Texas 79409, United States
| | - Hans Lischka
- Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, Texas 79409-1061, United States
| | - Dana Nachtigallova
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Flemingovo nam. 2, CZ-16610 Prague 6, Czech Republic
- IT4Innovations, VŠB-Technical University of Ostrava, 17. listopadu 2172/15, 70800 Ostrava-Poruba, Czech Republic
| | - Francisco B C Machado
- Departamento de Química, Instituto Tecnológico de Aeronáutica, São José dos Campos 122228-900, SP, Brazil
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5
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Bennett TLR, Marsh AV, Turner JM, Plasser F, Heeney M, Glöcklhofer F. Functionalisation of conjugated macrocycles with type I and II concealed antiaromaticity via cross-coupling reactions. MOLECULAR SYSTEMS DESIGN & ENGINEERING 2023; 8:713-720. [PMID: 37288099 PMCID: PMC10243434 DOI: 10.1039/d3me00045a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/22/2023] [Accepted: 05/03/2023] [Indexed: 06/09/2023]
Abstract
Conjugated macrocycles can exhibit concealed antiaromaticity; that is, despite not being antiaromatic, under specific circumstances, they can display properties typically observed in antiaromatic molecules due to their formal macrocyclic 4n π-electron system. Paracyclophanetetraene (PCT) and its derivatives are prime examples of macrocycles exhibiting this behaviour. In redox reactions and upon photoexcitation, they have been shown to behave like antiaromatic molecules (requiring type I and II concealed antiaromaticity, respectively), with such phenomena showing potential for use in battery electrode materials and other electronic applications. However, further exploration of PCTs has been hindered by the lack of halogenated molecular building blocks that would permit their integration into larger conjugated molecules by cross-coupling reactions. Here, we present two dibrominated PCTs, obtained as a mixture of regioisomers from a three-step synthesis, and demonstrate their functionalisation via Suzuki cross-coupling reactions. Optical, electrochemical, and theoretical studies reveal that aryl substituents can subtly tune the properties and behaviour of PCT, showing that this is a viable strategy in further exploring this promising class of materials.
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Affiliation(s)
- Troy L R Bennett
- Department of Chemistry and Centre for Processable Electronics, Imperial College London, Molecular Sciences Research Hub London UK
| | - Adam V Marsh
- KAUST Solar Center (KSC), Physical Science and Engineering Division (PSE), King Abdullah University of Science and Technology (KAUST) Thuwal Saudi Arabia
| | - James M Turner
- Department of Chemistry, Loughborough University Loughborough LE11 3TU UK
| | - Felix Plasser
- Department of Chemistry, Loughborough University Loughborough LE11 3TU UK
| | - Martin Heeney
- Department of Chemistry and Centre for Processable Electronics, Imperial College London, Molecular Sciences Research Hub London UK
- KAUST Solar Center (KSC), Physical Science and Engineering Division (PSE), King Abdullah University of Science and Technology (KAUST) Thuwal Saudi Arabia
| | - Florian Glöcklhofer
- Department of Chemistry and Centre for Processable Electronics, Imperial College London, Molecular Sciences Research Hub London UK
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6
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Eder S, Ding B, Thornton DB, Sammut D, White AJP, Plasser F, Stephens IEL, Heeney M, Mezzavilla S, Glöcklhofer F. Squarephaneic Tetraanhydride: A Conjugated Square-Shaped Cyclophane for the Synthesis of Porous Organic Materials. ANGEWANDTE CHEMIE (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2022; 134:e202212623. [PMID: 38504923 PMCID: PMC10947162 DOI: 10.1002/ange.202212623] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/26/2022] [Indexed: 11/10/2022]
Abstract
Aromatic carboxylic anhydrides are ubiquitous building blocks in organic materials chemistry and have received considerable attention in the synthesis of organic semiconductors, pigments, and battery electrode materials. Here we extend the family of aromatic carboxylic anhydrides with a unique new member, a conjugated cyclophane with four anhydride groups. The cyclophane is obtained in a three-step synthesis and can be functionalised efficiently, as shown by the conversion into tetraimides and an octacarboxylate. Crystal structures reveal the high degree of porosity achievable with the new building block. Excellent electrochemical properties and reversible reduction to the tetraanions are shown for the imides; NMR and EPR measurements confirm the global aromaticity of the dianions and evidence the global Baird aromaticity of the tetraanions. Considering the short synthesis and unique properties, we expect widespread use of the new building block in the development of organic materials.
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Affiliation(s)
- Simon Eder
- Department of ChemistryImperial College LondonMolecular Sciences Research HubLondonW12 0BZUK
- Centre for Processable ElectronicsImperial College LondonMolecular Sciences Research HubLondonW12 0BZUK
| | - Bowen Ding
- Department of ChemistryImperial College LondonMolecular Sciences Research HubLondonW12 0BZUK
- Centre for Processable ElectronicsImperial College LondonMolecular Sciences Research HubLondonW12 0BZUK
| | - Daisy B. Thornton
- Department of MaterialsImperial College LondonRoyal School of MinesLondonSW7 2AZUK
- The Faraday InstitutionHarwell Science and Innovation CampusDidcotOX11 0RAUK
| | - Darlene Sammut
- Department of ChemistryImperial College LondonMolecular Sciences Research HubLondonW12 0BZUK
- Centre for Processable ElectronicsImperial College LondonMolecular Sciences Research HubLondonW12 0BZUK
| | - Andrew J. P. White
- Department of ChemistryImperial College LondonMolecular Sciences Research HubLondonW12 0BZUK
| | - Felix Plasser
- Department of ChemistryLoughborough UniversityLoughboroughLE11 3TUUK
| | - Ifan E. L. Stephens
- Department of MaterialsImperial College LondonRoyal School of MinesLondonSW7 2AZUK
- The Faraday InstitutionHarwell Science and Innovation CampusDidcotOX11 0RAUK
| | - Martin Heeney
- Department of ChemistryImperial College LondonMolecular Sciences Research HubLondonW12 0BZUK
- Centre for Processable ElectronicsImperial College LondonMolecular Sciences Research HubLondonW12 0BZUK
| | - Stefano Mezzavilla
- Department of MaterialsImperial College LondonRoyal School of MinesLondonSW7 2AZUK
| | - Florian Glöcklhofer
- Department of ChemistryImperial College LondonMolecular Sciences Research HubLondonW12 0BZUK
- Centre for Processable ElectronicsImperial College LondonMolecular Sciences Research HubLondonW12 0BZUK
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7
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Eder S, Ding B, Thornton DB, Sammut D, White AJP, Plasser F, Stephens IEL, Heeney M, Mezzavilla S, Glöcklhofer F. Squarephaneic Tetraanhydride: A Conjugated Square-Shaped Cyclophane for the Synthesis of Porous Organic Materials. Angew Chem Int Ed Engl 2022; 61:e202212623. [PMID: 36178733 PMCID: PMC9827958 DOI: 10.1002/anie.202212623] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2022] [Indexed: 01/12/2023]
Abstract
Aromatic carboxylic anhydrides are ubiquitous building blocks in organic materials chemistry and have received considerable attention in the synthesis of organic semiconductors, pigments, and battery electrode materials. Here we extend the family of aromatic carboxylic anhydrides with a unique new member, a conjugated cyclophane with four anhydride groups. The cyclophane is obtained in a three-step synthesis and can be functionalised efficiently, as shown by the conversion into tetraimides and an octacarboxylate. Crystal structures reveal the high degree of porosity achievable with the new building block. Excellent electrochemical properties and reversible reduction to the tetraanions are shown for the imides; NMR and EPR measurements confirm the global aromaticity of the dianions and evidence the global Baird aromaticity of the tetraanions. Considering the short synthesis and unique properties, we expect widespread use of the new building block in the development of organic materials.
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Affiliation(s)
- Simon Eder
- Department of ChemistryImperial College LondonMolecular Sciences Research HubLondonW12 0BZUK
- Centre for Processable ElectronicsImperial College LondonMolecular Sciences Research HubLondonW12 0BZUK
| | - Bowen Ding
- Department of ChemistryImperial College LondonMolecular Sciences Research HubLondonW12 0BZUK
- Centre for Processable ElectronicsImperial College LondonMolecular Sciences Research HubLondonW12 0BZUK
| | - Daisy B. Thornton
- Department of MaterialsImperial College LondonRoyal School of MinesLondonSW7 2AZUK
- The Faraday InstitutionHarwell Science and Innovation CampusDidcotOX11 0RAUK
| | - Darlene Sammut
- Department of ChemistryImperial College LondonMolecular Sciences Research HubLondonW12 0BZUK
- Centre for Processable ElectronicsImperial College LondonMolecular Sciences Research HubLondonW12 0BZUK
| | - Andrew J. P. White
- Department of ChemistryImperial College LondonMolecular Sciences Research HubLondonW12 0BZUK
| | - Felix Plasser
- Department of ChemistryLoughborough UniversityLoughboroughLE11 3TUUK
| | - Ifan E. L. Stephens
- Department of MaterialsImperial College LondonRoyal School of MinesLondonSW7 2AZUK
- The Faraday InstitutionHarwell Science and Innovation CampusDidcotOX11 0RAUK
| | - Martin Heeney
- Department of ChemistryImperial College LondonMolecular Sciences Research HubLondonW12 0BZUK
- Centre for Processable ElectronicsImperial College LondonMolecular Sciences Research HubLondonW12 0BZUK
| | - Stefano Mezzavilla
- Department of MaterialsImperial College LondonRoyal School of MinesLondonSW7 2AZUK
| | - Florian Glöcklhofer
- Department of ChemistryImperial College LondonMolecular Sciences Research HubLondonW12 0BZUK
- Centre for Processable ElectronicsImperial College LondonMolecular Sciences Research HubLondonW12 0BZUK
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8
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Plasser F, Krylov AI, Dreuw A. libwfa: Wavefunction analysis tools for excited and open‐shell electronic states. WIRES COMPUTATIONAL MOLECULAR SCIENCE 2022. [DOI: 10.1002/wcms.1595] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Affiliation(s)
- Felix Plasser
- Department of Chemistry Loughborough University Loughborough UK
| | - Anna I. Krylov
- Department of Chemistry University of Southern California California Los Angeles USA
| | - Andreas Dreuw
- Interdisciplinary Center for Scientific Computing Ruprecht‐Karls University Heidelberg Germany
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9
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Pletzer M, Plasser F, Rimmele M, Heeney M, Glöcklhofer F. [2.2.2.2]Paracyclophanetetraenes (PCTs): cyclic structural analogues of poly( p‑phenylene vinylene)s (PPVs). OPEN RESEARCH EUROPE 2022; 1:111. [PMID: 37645175 PMCID: PMC10445936 DOI: 10.12688/openreseurope.13723.2] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 03/03/2022] [Indexed: 08/31/2023]
Abstract
Background: Poly( p-phenylene vinylene)s ( PPVs) and [2.2.2.2]paracyclophanetetraene ( PCT) are both composed of alternating π-conjugated para-phenylene and vinylene units. However, while the former constitute a class of π-conjugated polymers that has been used in organic electronics for decades, the latter is a macrocycle that only recently revealed its potential for applications such as organic battery electrodes. The cyclic structure endows PCT with unusual properties, and further tuning of these may be required for specific applications. Methods: In this article, we adopt an approach often used for tuning the properties of PPVs, the introduction of alkoxy (or alkylthio) substituents at the phenylene units, for tuning the optoelectronic properties of PCT. The resulting methoxy- and methylthio-substituted PCTs, obtained by Wittig cyclisation reactions, are studied by UV-vis absorption, photoluminescence, and cyclic voltammetry measurements, and investigated computationally using the visualisation of chemical shielding tensors (VIST) method. Results: The measurements show that substitution leads to slight changes in terms of absorption/emission energies and redox potentials while having a pronounced effect on the photoluminescence intensity. The computations show the effect of the substituents on the ring currents and chemical shielding and on the associated local and global (anti)aromaticity of the macrocycles, highlighting the interplay of local and global aromaticity in various electronic states. Conclusions: The study offers interesting insights into the tuneability of the properties of this versatile class of π-conjugated macrocycles.
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Affiliation(s)
- Matthias Pletzer
- Department of Chemistry, Imperial College London, London, W12 0BZ, UK
- Centre for Processable Electronics, Imperial College London, London, W12 0BZ, UK
| | - Felix Plasser
- Department of Chemistry, Loughborough University, Loughborough, LE11 3TU, UK
| | - Martina Rimmele
- Department of Chemistry, Imperial College London, London, W12 0BZ, UK
- Centre for Processable Electronics, Imperial College London, London, W12 0BZ, UK
| | - Martin Heeney
- Department of Chemistry, Imperial College London, London, W12 0BZ, UK
- Centre for Processable Electronics, Imperial College London, London, W12 0BZ, UK
| | - Florian Glöcklhofer
- Department of Chemistry, Imperial College London, London, W12 0BZ, UK
- Centre for Processable Electronics, Imperial College London, London, W12 0BZ, UK
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10
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Chen Y, Tseng SM, Chang KH, Chou PT. Energy Counterbalance to Harness Photoinduced Structural Planarization of Dibenzo[b,f]azepines toward Thermal Reversibility. J Am Chem Soc 2022; 144:1748-1757. [DOI: 10.1021/jacs.1c11231] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Affiliation(s)
- Yi Chen
- Department of Chemistry, National Taiwan University, Taipei 10617, Taiwan, Republic of China
| | - Sheng-Ming Tseng
- Department of Chemistry, National Taiwan University, Taipei 10617, Taiwan, Republic of China
| | - Kai-Hsin Chang
- Department of Chemistry, National Taiwan University, Taipei 10617, Taiwan, Republic of China
| | - Pi-Tai Chou
- Department of Chemistry, National Taiwan University, Taipei 10617, Taiwan, Republic of China
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11
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Zeng Y, Yang J, Zheng X. Aggregation effects on photophysical properties of NBN-doped polycyclic aromatic hydrocarbons: a theoretical study. Phys Chem Chem Phys 2021; 23:23986-23997. [PMID: 34664048 DOI: 10.1039/d1cp03726a] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
To realize the precise manipulation of the optoelectrical properties of boron-nitrogen (B-N) unit-doped polycyclic aromatic hydrocarbons (PAHs), unraveling the structure-property relationship behind them is of vital importance. In this work, we take two representative NBN-doped PAHs with similar structures (NBN-5 and NBN-6) as examples and explore the influence of molecular packing on their photophysical properties in different environments (including dilute solution, amorphous aggregate and crystal) using a theoretical protocol that combines molecular dynamics (MD) simulations and thermal vibration correlation function coupled quantum mechanics/molecular mechanics (QM/MM) calculations. We found that the different symmetries of the transition orbitals in NBN-5 and NBN-6 lead to their distinct distributions of transition orbitals, with NBN-5 delocalizing on the whole backbone and NBN-6 bearing clear intramolecular charge transfer. Therefore, the S1 state of NBN-6 demonstrates redshifted emission spectra in contrast to those of NBN-5. We confirmed that NBN-6 in dilute solution is more flexible than NBN-6 in aggregated states. After aggregation, the fluorescent quantum efficiency (FQE) of NBN-6 increases significantly with the nonradiative decay constants decreasing by 2-4 orders of magnitude, because the dense molecular packing in the aggregated state could effectively suppress the out-of-plane rotation and distortion of the phenyl-ring at the boron position, indicating its AIE feature. While the photophysical properties of conjugated NBN-5 with high rigidity are independent of the environment, showing bright emission in both solution and solid states, consistent with the experimental results. Our theoretical protocol is general and applicable to other doped PAHs, thus laying a solid foundation for the rational design of advanced materials.
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Affiliation(s)
- Yi Zeng
- Key Laboratory of Cluster Science of Ministry of Education, Beijing Key laboratory of Photoelectronic/Electro-photonic Conversion Materials, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing, 100081, China.
| | - Junfang Yang
- Key Laboratory of Cluster Science of Ministry of Education, Beijing Key laboratory of Photoelectronic/Electro-photonic Conversion Materials, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing, 100081, China.
| | - Xiaoyan Zheng
- Key Laboratory of Cluster Science of Ministry of Education, Beijing Key laboratory of Photoelectronic/Electro-photonic Conversion Materials, School of Chemistry and Chemical Engineering, Beijing Institute of Technology, Beijing, 100081, China. .,Guangdong Provincial Key Laboratory of Luminescence from Molecular Aggregates (South China University of Technology), Guangzhou 510640, China
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12
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Artigas A, Hagebaum-Reignier D, Carissan Y, Coquerel Y. Visualizing electron delocalization in contorted polycyclic aromatic hydrocarbons. Chem Sci 2021; 12:13092-13100. [PMID: 34745540 PMCID: PMC8513938 DOI: 10.1039/d1sc03368a] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2021] [Accepted: 09/03/2021] [Indexed: 11/21/2022] Open
Abstract
Electron delocalization in contorted polycyclic aromatic hydrocarbon (PAH) molecules was examined through 3D isotropic magnetic shielding (IMS) contour maps built around the molecules using pseudo-van der Waals surfaces. The resulting maps of electron delocalization provided an intuitive, yet detailed and quantitative evaluation of the aromatic, non aromatic, and antiaromatic character of the local and global conjugated cyclic circuits distributed over the molecules. An attractive pictural feature of the 3D IMS contour maps is that they are reminiscent of the Clar π-sextet model of aromaticity. The difference in delocalization patterns between the two faces of the electron circuits in contorted PAHs was clearly visualized. For π-extended contorted PAHs, some splits of the π system resulted in recognizable patterns typical of smaller PAHs. The differences between the delocalization patterns of diastereomeric chiral PAHs could also be visualized. Mapping IMS on pseudo-van der Waals surfaces around contorted PAHs allowed visualization of their superimposed preferred circuits for electron delocalization and hence their local and global aromaticity patterns.
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Affiliation(s)
- Albert Artigas
- Aix Marseille Université, CNRS, Centrale Marseille, ISM2 13397 Marseille France
| | | | - Yannick Carissan
- Aix Marseille Université, CNRS, Centrale Marseille, ISM2 13397 Marseille France
| | - Yoann Coquerel
- Aix Marseille Université, CNRS, Centrale Marseille, ISM2 13397 Marseille France
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Rimmele M, Nogala W, Seif-Eddine M, Roessler MM, Heeney M, Plasser F, Glöcklhofer F. Functional group introduction and aromatic unit variation in a set of π-conjugated macrocycles: revealing the central role of local and global aromaticity. Org Chem Front 2021; 8:4730-4745. [PMID: 34484800 PMCID: PMC8382046 DOI: 10.1039/d1qo00901j] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2021] [Accepted: 06/17/2021] [Indexed: 12/18/2022]
Abstract
π-Conjugated macrocycles are molecules with unique properties that are increasingly exploited for applications and the question of whether they can sustain global aromatic or antiaromatic ring currents is particularly intriguing. However, there are only a small number of experimental studies that investigate how the properties of π-conjugated macrocycles evolve with systematic structural changes. Here, we present such a systematic experimental study of a set of [2.2.2.2]cyclophanetetraenes, all with formally Hückel antiaromatic ground states, and combine it with an in-depth computational analysis. The study reveals the central role of local and global aromaticity for rationalizing the observed optoelectronic properties, ranging from extremely large Stokes shifts of up to 1.6 eV to reversible fourfold reduction, a highly useful feature for charge storage/accumulation applications. A recently developed method for the visualization of chemical shielding tensors (VIST) is applied to provide unique insight into local and global ring currents occurring in different planes along the macrocycle. Conformational changes as a result of the structural variations can further explain some of the observations. The study contributes to the development of structure-property relationships and molecular design guidelines and will help to understand, rationalize, and predict the properties of other π-conjugated macrocycles. It will also assist in the design of macrocycle-based supramolecular elements with defined properties.
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Affiliation(s)
- Martina Rimmele
- Department of Chemistry, Imperial College London London W12 0BZ UK .,Centre for Processable Electronics, Imperial College London London W12 0BZ UK
| | - Wojciech Nogala
- Institute of Physical Chemistry, Polish Academy of Sciences Kasprzaka 44/52 01-224 Warsaw Poland
| | | | - Maxie M Roessler
- Department of Chemistry, Imperial College London London W12 0BZ UK
| | - Martin Heeney
- Department of Chemistry, Imperial College London London W12 0BZ UK .,Centre for Processable Electronics, Imperial College London London W12 0BZ UK
| | - Felix Plasser
- Department of Chemistry, Loughborough University Loughborough LE11 3TU UK
| | - Florian Glöcklhofer
- Department of Chemistry, Imperial College London London W12 0BZ UK .,Centre for Processable Electronics, Imperial College London London W12 0BZ UK
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Exploitation of Baird Aromaticity and Clar’s Rule for Tuning the Triplet Energies of Polycyclic Aromatic Hydrocarbons. CHEMISTRY 2021. [DOI: 10.3390/chemistry3020038] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Polycyclic aromatic hydrocarbons (PAH) are a prominent substance class with a variety of applications in molecular materials science. Their electronic properties crucially depend on the bond topology in ways that are often highly non-intuitive. Here, we study, using density functional theory, the triplet states of four biphenylene-derived PAHs finding dramatically different triplet excitation energies for closely related isomeric structures. These differences are rationalised using a qualitative description of Clar sextets and Baird quartets, quantified in terms of nucleus independent chemical shifts, and represented graphically through a recently developed method for visualising chemical shielding tensors (VIST). The results are further interpreted in terms of a 2D rigid rotor model of aromaticity and through an analysis of the natural transition orbitals involved in the triplet excited states showing good consistency between the different viewpoints. We believe that this work constitutes an important step in consolidating these varying viewpoints of electronically excited states.
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