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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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Li S, Chen J. Synthesis and Properties of Novel Alkyl-Substituted Hexaazacyclophanes and Their Diradical Dications. Molecules 2024; 29:789. [PMID: 38398541 PMCID: PMC10893516 DOI: 10.3390/molecules29040789] [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: 01/21/2024] [Revised: 02/04/2024] [Accepted: 02/06/2024] [Indexed: 02/25/2024] Open
Abstract
Radicals based on arylamine cyclophanes can be used as functional materials and show application potential in fields such as synthetic chemistry, molecular electronic components, organic light-emitting diodes, and catalytic chemistry. Using a Buchwald-Hartwig palladium-catalyzed aryl halide amination method, we synthesized a series of neutral hexaazacyclophane compounds 1-3 with different substituents in the meta-meta-meta positions of the phenyl rings. Three characteristic high-spin hexaazacyclophane diradical dications were obtained by two-electron oxidation using AgSbF6: 12·+•2[SbF6]-, 22·+•2[SbF6]-, and 32·+•2[SbF6]-. The electronic structures and physical properties of these compounds were then investigated by 1H and 13C nuclear magnetic resonance spectroscopy, cyclic voltammetry, electron paramagnetic resonance spectroscopy, superconducting quantum interferometry, ultraviolet-visible spectroscopy, and density functional theory calculations. The findings provide new ideas for designing radical species with novel physical properties and electronic structures. Importantly, the obtained radical species are not sensitive to air, making them valuable functional materials for practical applications.
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Affiliation(s)
- Shunjie Li
- College of Chemistry and Materials Science, Anhui Normal University, Wuhu 241000, China
| | - Jian Chen
- College of Chemistry and Materials Science, Huaibei Normal University, Huaibei 235000, China
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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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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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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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