1
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Mutoh K, Abe J. Fast photochromism of helicene-bridged imidazole dimers. Chem Sci 2024; 15:13343-13350. [PMID: 39183935 PMCID: PMC11339945 DOI: 10.1039/d4sc03578j] [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: 05/31/2024] [Accepted: 07/19/2024] [Indexed: 08/27/2024] Open
Abstract
The unique optical and magnetic properties of organic biradicaloids on polycyclic aromatic hydrocarbons are of fundamental interest in the development of novel organic optoelectronic materials. Open-shell π-conjugated molecules with helicity have recently attracted a great deal of attention due to the magnetic-field-dependence and spin-selectivity arising from the combination of helical chirality and electron spins. However, the molecular design for helical biradicaloids is limited due to the thermal instability and high reactivity. Herein, we achieved fast photochromic reactions and reversible photo-generation of biradical species using helicene-bridged imidazole dimers. A [9]helicene-bridged imidazole dimer exhibits reversible photochromism upon UV light irradiation. The transient species produced reversibly by UV light irradiation exhibited ESR spectra with a fine structure characteristic of a triplet radical pair, indicating the reversible generation of the biradical. The half-life of the thermal recombination reaction of the biradical was estimated to be 29 ms at 298 K. Conversely, a substantial activation energy barrier was confirmed for the intramolecular recombination reaction in the [7]helicene-bridged imidazole dimer, attributed to the extended pitch length of [7]helicene. The temperature dependence of the thermal back reactions revealed that the [7]helicene and [9]helicene moieties functioned as 'soft' and 'hard' molecular bridges, respectively. These findings pave the way for future advances in the development of photoswitchable helical biradicaloids.
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Affiliation(s)
- Katsuya Mutoh
- Department of Chemistry and Biological Science, College of Science and Engineering, Aoyama Gakuin University Sagamihara Kanagawa 252-5258 Japan
| | - Jiro Abe
- Department of Chemistry and Biological Science, College of Science and Engineering, Aoyama Gakuin University Sagamihara Kanagawa 252-5258 Japan
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2
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Jiang Q, Tang H, Peng Y, Hu Z, Zeng W. Helical polycyclic hydrocarbons with open-shell singlet ground states and ambipolar redox behaviors. Chem Sci 2024; 15:10519-10528. [PMID: 38994409 PMCID: PMC11234857 DOI: 10.1039/d4sc02116a] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2024] [Accepted: 05/28/2024] [Indexed: 07/13/2024] Open
Abstract
Organic π-conjugated polycyclic hydrocarbons (PHs) with an open-shell diradical character are attracting increasing interest due to their promising applications in organic electronics and spintronics. However, most of the open-shell PHs synthesized thus far are based on planar π-conjugated molecules. Herein, we report the synthesis and characterization of two new quinodimethane-embedded expanded helicenes H1 and H2. The helical structures of both molecules were revealed using X-ray crystallographic analysis. It was elucidated in detailed experimental and theoretical studies that they possess an open-shell singlet biradical structure in the ground state and show a small energy gap and amphoteric redox behavior. Both compounds can also be easily oxidized or reduced into relatively stable charged species. The dianions of H1 and H2 exhibit similar electronic structures to the respective isoelectronic structures of their all-benzenoid helical analogues according to NMR measurements and theoretical calculations. Moreover, the structures of the dication and dianion of H2 were identified by X-ray crystallographic analysis, revealing the effect of electron transfer on their backbones and aromaticity. This study thus opens up new avenues for both helical polycyclic π-systems and diradicaloids.
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Affiliation(s)
- Qing Jiang
- College of Chemistry and Bioengineering, Hunan University of Science and Engineering Yongzhou 425100 China
| | - Hui Tang
- College of Chemistry and Bioengineering, Hunan University of Science and Engineering Yongzhou 425100 China
| | - Yuchen Peng
- College of Chemistry and Bioengineering, Hunan University of Science and Engineering Yongzhou 425100 China
| | - Zhenni Hu
- College of Chemistry and Bioengineering, Hunan University of Science and Engineering Yongzhou 425100 China
| | - Wangdong Zeng
- School of Materials Science and Engineering, Hunan University of Science and Technology Xiangtan 411201 China
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3
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Radenković S, Đorđević S, Nikolendžić M. Effect of Benzo-Annelation on Triplet State Energies in Polycyclic Conjugated Hydrocarbons. Chemistry 2024; 30:e202400361. [PMID: 38488676 DOI: 10.1002/chem.202400361] [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: 01/27/2024] [Indexed: 04/09/2024]
Abstract
In a series of earlier studies, the effect of benzo-annelation was found to be a useful tool for tuning the aromaticity in polycyclic conjugated compounds to desired level. In this work we studied the (anti)aromaticity of benzo-annelated derivatives of three conjugated hydrocarbons (anthracene, fluoranthene and biphenylene) in their lowest lying singlet (S0) and triplet (T1) states by means of the energy effect (ef), harmonic oscillator model of aromaticity (HOMA), multicentre delocalization indices (MCI), magnetically induced current densities (MICDs) and nucleus independent chemical shifts (NICS). We showed that benzo-annelation is a topology-based effect which can be used to modify the T1 state excitation energies (E(T1)). A quantitative model was established being able to accurately predict the E(T1) based only on the numbers of angularly, linearly and geminally annelated benzene rings. In addition, it was demonstrated that the E(T1) can be directly related to the (anti)aromatic character of the central ring in the studied molecules in their S0 state.
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Affiliation(s)
- Slavko Radenković
- University of Kragujevac, Faculty of Science, P.O. Box 60, Kragujevac, 34000, Serbia
| | - Slađana Đorđević
- University of Kragujevac, Faculty of Science, P.O. Box 60, Kragujevac, 34000, Serbia
| | - Marijana Nikolendžić
- University of Kragujevac, Faculty of Science, P.O. Box 60, Kragujevac, 34000, Serbia
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4
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Nikulshin PV, Makarov AY, Koskin IP, Becker CS, Kazantsev MS, Beckmann J, Balmohammadi Y, Grabowsky S, Mebs S, Naumova OV, Protasov DY, Svit KA, Irtegova IG, Radiush EA, Bagryanskaya IY, Shundrin LA, Zibarev AV. 1,2,3,4-Tetrafluorobiphenylene: A Prototype Janus-Headed Scaffold for Ambipolar Materials. Chempluschem 2024; 89:e202300692. [PMID: 38052725 DOI: 10.1002/cplu.202300692] [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: 11/26/2023] [Revised: 12/01/2023] [Accepted: 12/05/2023] [Indexed: 12/07/2023]
Abstract
The title compound was synthesized by Ullmann cross-coupling in low yield as the first representative of [n]phenylene containing hydrocarbon and fluorocarbon rings. Stille/Suzuki-Miyaura cross-coupling reactions, as well as substitution of fluorine in suitable starting compounds, failed to give the same product. The geometric and electronic structures of the title compound were studied by X-ray diffraction, cyclic voltammetry and density functional theory calculations, together with Hirshfeld surface and reduced density gradient analyses. The crystal structure features head-to-tail π-stacking and other fluorine-related secondary bonding interactions. From the nucleus-independent chemical shifts descriptor, the four-membered ring of the title compound is antiaromatic, and the six-membered rings are aromatic. The Janus molecule is highly polarized; and the six-membered fluoro- and hydrocarbon rings are Lewis π-acidic and π-basic, respectively. The electrochemically-generated radical cation of the title compound is long-lived as characterized by electron paramagnetic resonance, whereas the radical anion is unstable in solution. The title compound reveals electrical properties of an insulator. On expanding its molecular scaffold towards partially fluorinated [n]phenylenes (n≥2), the properties presumably can be transformed into those of semiconductors. In this context, the title compound is suggested as a prototype scaffold for ambipolar materials for organic electronics and spintronics.
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Affiliation(s)
- Pavel V Nikulshin
- Vorozhtsov Novosibirsk Institute of Organic Chemistry, Siberian Branch of the Russian Academy of Sciences, 630090, Novosibirsk, Russia
- Current address: Topchiev Institute of Petrochemical Synthesis, Russian Academy of Sciences, 119991, Moscow, Russia
| | - Alexander Yu Makarov
- Vorozhtsov Novosibirsk Institute of Organic Chemistry, Siberian Branch of the Russian Academy of Sciences, 630090, Novosibirsk, Russia
| | - Igor P Koskin
- Vorozhtsov Novosibirsk Institute of Organic Chemistry, Siberian Branch of the Russian Academy of Sciences, 630090, Novosibirsk, Russia
| | - Christina S Becker
- Vorozhtsov Novosibirsk Institute of Organic Chemistry, Siberian Branch of the Russian Academy of Sciences, 630090, Novosibirsk, Russia
| | - Maxim S Kazantsev
- Vorozhtsov Novosibirsk Institute of Organic Chemistry, Siberian Branch of the Russian Academy of Sciences, 630090, Novosibirsk, Russia
| | - Jens Beckmann
- Institute for Inorganic Chemistry and Crystallography, University of Bremen, 28359, Bremen, Germany
| | - Yaser Balmohammadi
- Department of Chemistry, Biochemistry and Pharmaceutical Science, University of Bern, 3012, Bern, Switzerland
| | - Simon Grabowsky
- Department of Chemistry, Biochemistry and Pharmaceutical Science, University of Bern, 3012, Bern, Switzerland
| | - Stefan Mebs
- Institute for Experimental Physics, Free University of Berlin, 14195, Berlin, Germany
| | - Olga V Naumova
- Rzhanov Institute of Semiconductor Physics, Siberian Branch of the Russian Academy of Sciences, 630090, Novosibirsk, Russia
| | - Dmitry Yu Protasov
- Rzhanov Institute of Semiconductor Physics, Siberian Branch of the Russian Academy of Sciences, 630090, Novosibirsk, Russia
| | - Kirill A Svit
- Rzhanov Institute of Semiconductor Physics, Siberian Branch of the Russian Academy of Sciences, 630090, Novosibirsk, Russia
| | - Irina G Irtegova
- Vorozhtsov Novosibirsk Institute of Organic Chemistry, Siberian Branch of the Russian Academy of Sciences, 630090, Novosibirsk, Russia
| | - Ekaterina A Radiush
- Vorozhtsov Novosibirsk Institute of Organic Chemistry, Siberian Branch of the Russian Academy of Sciences, 630090, Novosibirsk, Russia
| | - Irina Yu Bagryanskaya
- Vorozhtsov Novosibirsk Institute of Organic Chemistry, Siberian Branch of the Russian Academy of Sciences, 630090, Novosibirsk, Russia
| | - Leonid A Shundrin
- Vorozhtsov Novosibirsk Institute of Organic Chemistry, Siberian Branch of the Russian Academy of Sciences, 630090, Novosibirsk, Russia
| | - Andrey V Zibarev
- Vorozhtsov Novosibirsk Institute of Organic Chemistry, Siberian Branch of the Russian Academy of Sciences, 630090, Novosibirsk, Russia
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5
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Hu C, Kuhn L, Makurvet FD, Knorr ES, Lin X, Kawade RK, Mentink-Vigier F, Hanson K, Alabugin IV. Tethering Three Radical Cascades for Controlled Termination of Radical Alkyne peri-Annulations: Making Phenalenyl Ketones without Oxidants. J Am Chem Soc 2024; 146:4187-4211. [PMID: 38316011 DOI: 10.1021/jacs.3c13371] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2024]
Abstract
Although Bu3Sn-mediated radical alkyne peri-annulations allow access to phenalenyl ring systems, the oxidative termination of these cascades provides only a limited selection of the possible isomeric phenalenone products with product selectivity controlled by the intrinsic properties of the new cyclic systems. In this work, we report an oxidant-free termination strategy that can overcome this limitation and enable selective access to the full set of isomerically functionalized phenalenones. The key to preferential termination is the preinstallation of a "weak link" that undergoes C-O fragmentation in the final cascade step. Breaking a C-O bond is assisted by entropy, gain of conjugation in the product, and release of stabilized radical fragments. This strategy is expanded to radical exo-dig cyclization cascades of oligoalkynes, which provide access to isomeric π-extended phenalenones. Conveniently, these cascades introduce functionalities (i.e., Bu3Sn and iodide moieties) amenable to further cross-coupling reactions. Consequently, a variety of polyaromatic diones, which could serve as phenalenyl-based open-shell precursors, can be synthesized.
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Affiliation(s)
- Chaowei Hu
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, Florida 32306-4390, United States
| | - Leah Kuhn
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, Florida 32306-4390, United States
| | - Favour D Makurvet
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, Florida 32306-4390, United States
| | - Erica S Knorr
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, Florida 32306-4390, United States
| | - Xinsong Lin
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, Florida 32306-4390, United States
| | - Rahul K Kawade
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, Florida 32306-4390, United States
| | - Frederic Mentink-Vigier
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, Florida 32310, United States
| | - Kenneth Hanson
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, Florida 32306-4390, United States
| | - Igor V Alabugin
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, Florida 32306-4390, United States
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6
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Shil S, Bhattacharya D, Misra A, Bytautas L. Antiaromatic Molecules as Magnetic Couplers: A Computational Quest. J Phys Chem A 2024; 128:815-828. [PMID: 38267395 PMCID: PMC10860145 DOI: 10.1021/acs.jpca.3c05784] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2023] [Revised: 12/28/2023] [Accepted: 01/03/2024] [Indexed: 01/26/2024]
Abstract
In this study, we investigate a set of organic diradical structures in which two oxo-verdazyl radicals are selected as radical spin centers that are connected (coupled) via six coupler molecules (CM), resulting in various magnetic (ferromagnetic (FM) or antiferromagnetic (AFM)) characteristics, as reflected by their exchange coupling constants (J). We have designed 12 diradicals with 6-antiaromatic couplers coupled with bis-oxo-verdazyl diradicals with meta-meta (m-m) and para-meta (p-m) positional connectivities. The nature of the magnetic coupling (ferromagnetic, nonmagnetic, or antiferromagnetic) and the magnitude of the exchange constant J depend on the type of coupler, the connecting point between each radical center and CM, the degree of aromaticity of the coupler, and the length of the through-bond distance between radical centers. The computed magnetic exchange coupling constants J for these diradicals at the B3LYP/6-311++G(d,p) and MN12SX/6-311++G(d,p) levels of theory are large for many of these structures, indicating strong ferromagnetic coupling (with positive J values). In some cases, magnetic couplings are observed with J > 1000 cm-1 (B3LYP/6-311++G(d,p)) and strong antiferromagnetic coupling (with negative J values) with J < -1000 cm-1 (B3LYP/6-311++G(d,p)). Similarly, in some cases, magnetic couplings are observed with J > 289 cm-1 (MN12SX/6-311++G(d,p)) and strong antiferromagnetic coupling (with negative J values) with J < -568 cm-1 (MN12SX/6-311++G(d,p)). Furthermore, while numerous studies have reported that the degree of aromaticity of molecular couplers often favors strong ferromagnetic coupling, displaying the high-spin character of diradicals in their ground states, the couplers chosen in this study are characterized as antiaromatic or nonaromatic. The current investigation provides evidence that, remarkably, antiaromatic couplers are able to enhance stability by favoring electronic diradical structures with very strong ferromagnetic coupling when the length of the through-bond distance and connectivity pattern between radical centers are selected in such a way that the FM coupling is optimized. The findings in this study offer new strategies in the design of novel organic materials with interesting magnetic properties for practical applications.
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Affiliation(s)
- Suranjan Shil
- Manipal
Centre for Natural Sciences (Centre of Excellence), Manipal Academy of Higher Education, Manipal 576104, India
| | | | - Anirban Misra
- Department
of Chemistry, University of North Bengal, Raja Rammohunpur, Siliguri 734013, India
| | - Laimutis Bytautas
- Department
of Chemistry, Galveston College, 4015 Avenue Q, Galveston, Texas 77550, United States
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7
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Moriyasu R, Quintero SM, Gómez-García CJ, Suzuki K, Kitamura C, Murata M, Alonso M, Casado J, Kato SI. Isomerism tunes the diradical character of difluorenopyrroles at constant Hückel-level anti-aromaticity. Chem Sci 2023; 14:13468-13474. [PMID: 38033889 PMCID: PMC10685319 DOI: 10.1039/d3sc03297c] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2023] [Accepted: 10/22/2023] [Indexed: 12/02/2023] Open
Abstract
A new diradical based on diindenocarbazole or difluorenopyrrole was synthesized and experimentally characterized by optical, electrochemical, and magnetic techniques, as well as quantum chemical calculations. The isomerism of these structures tunes the diradical character and the associated properties, representing a unique case of such important modulation. A full study of the electronic structure was carried out considering the perturbative interactions between different canonical forms as well as the anti-aromatic character of the molecular cores. Such a study reveals how we can tune diradical character simply by reorganizing the bonding patterns at constant chemical costs (composition).
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Affiliation(s)
- Ryotaro Moriyasu
- Department of Materials Chemistry, School of Engineering, The University of Shiga Prefecture 2500 Hassaka-cho Hikone Shiga 522-8533 Japan
| | - Sergio Moles Quintero
- Departament of Physical Chemistry, University of Málaga Campus de Teatinos s/n Málaga 29071 Spain
| | - Carlos J Gómez-García
- Departament of Inorganic Chemsitry, University of Valencia C/ DR. Moliner, 50, 46100 Brujassot Valencia Spain
| | - Kazumasa Suzuki
- Department of Material Chemistry, Graduate School of Engineering, Nagoya university Furo-cho, Chikusa-ku Nagoya 464-8603 Japan
| | - Chitoshi Kitamura
- Department of Materials Chemistry, School of Engineering, The University of Shiga Prefecture 2500 Hassaka-cho Hikone Shiga 522-8533 Japan
| | - Michihisa Murata
- Department of Applied Chemistry, Faculty of Engineering, Osaka Institute of Technology 5-16-1 Ohmiya, Asahi-ku Osaka 535-8585 Japan
| | - Mercedes Alonso
- Eenheid Algemene Chemie (ALGC), Vrije Universiteit Brussel (VUB)Plei nlaan 2 1050 Brussels Belgium
| | - Juan Casado
- Departament of Physical Chemistry, University of Málaga Campus de Teatinos s/n Málaga 29071 Spain
| | - Shin-Ichiro Kato
- Department of Materials Chemistry, School of Engineering, The University of Shiga Prefecture 2500 Hassaka-cho Hikone Shiga 522-8533 Japan
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8
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Abdurahman A, Shen L, Wang J, Niu M, Li P, Peng Q, Wang J, Lu G. A highly efficient open-shell singlet luminescent diradical with strong magnetoluminescence properties. LIGHT, SCIENCE & APPLICATIONS 2023; 12:272. [PMID: 37963871 PMCID: PMC10645991 DOI: 10.1038/s41377-023-01314-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2023] [Revised: 10/14/2023] [Accepted: 10/23/2023] [Indexed: 11/16/2023]
Abstract
Developing open-shell singlet (OS) diradicals with high luminescent properties and exceptional single-molecule magnetoluminescence (ML) performance is extremely challenging. Herein, we propose a concept to enhance luminescent efficiency by adjusting the donor conjugation of OS diradicals, thereby achieving a highly luminescent diradical, DR1, with outstanding stability and making it a viable option for use in the emitting layer of organic light-emitting diodes (OLEDs). More importantly, the 0.5 wt%-DR1 doped film demonstrates significant single-molecule magnetoluminescence (ML) properties. A giant ML value of 210% is achieved at a magnetic field of 7 T, showing the great potential of DR1 in magneto-optoelectronic devices.
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Affiliation(s)
- Alim Abdurahman
- State Key Laboratory of Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, Qianjin Avenue 2699, Changchun, 130012, China.
| | - Li Shen
- College of Chemical Engineering and Environmental Chemistry, Weifang University, Weifang, 261061, China
| | - Jingmin Wang
- Key Laboratory of Flexible Electronics (KLOFE), Institute of Advanced Materials (IAM) & School of Flexible Electronics (Future Technologies), Nanjing Tech University (NanjingTech), 30 South Puzhu Road, Nanjing, 211816, China
| | - Meiling Niu
- Key Laboratory of Flexible Electronics (KLOFE), Institute of Advanced Materials (IAM) & School of Flexible Electronics (Future Technologies), Nanjing Tech University (NanjingTech), 30 South Puzhu Road, Nanjing, 211816, China
| | - Ping Li
- Key Laboratory for Organic Electronics and Information Displays & Institute of Advanced Materials (IAM) National Synergistic Innovation Center for Advanced Materials (SICAM), Nanjing University of Posts & Telecommunications, 9 Wenyuan Road, Nanjing, 210023, China
| | - Qiming Peng
- Key Laboratory of Flexible Electronics (KLOFE), Institute of Advanced Materials (IAM) & School of Flexible Electronics (Future Technologies), Nanjing Tech University (NanjingTech), 30 South Puzhu Road, Nanjing, 211816, China.
| | - Jianpu Wang
- Key Laboratory of Flexible Electronics (KLOFE), Institute of Advanced Materials (IAM) & School of Flexible Electronics (Future Technologies), Nanjing Tech University (NanjingTech), 30 South Puzhu Road, Nanjing, 211816, China
| | - Geyu Lu
- State Key Laboratory of Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, Qianjin Avenue 2699, Changchun, 130012, China.
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9
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Garner MH, Blaskovits JT, Corminboeuf C. Double-bond delocalization in non-alternant hydrocarbons induces inverted singlet-triplet gaps. Chem Sci 2023; 14:10458-10466. [PMID: 37800005 PMCID: PMC10548509 DOI: 10.1039/d3sc03409g] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2023] [Accepted: 09/06/2023] [Indexed: 10/07/2023] Open
Abstract
Molecules where the first excited singlet state is lower in energy than the first excited triplet state have the potential to revolutionize OLEDs. This inverted singlet-triplet gap violates Hund's rule and currently there are only a few molecules which are known to have this property. Here, we screen the complete set of non-alternant hydrocarbons consisting of 5-, 6-, 7-membered rings fused into two-, three- and four-ring polycyclic systems. We identify several molecules where the symmetry of the ground-state structure is broken due to bond-length alternation. Through symmetry-constrained optimizations we identify several molecular cores where the singlet-triplet gap is inverted when the structure is in a higher symmetry, pentalene being a known example. We uncover a strategy to stabilize the molecular cores into their higher-symmetry structures with electron donors or acceptors. We design several substituted pentalenes, s-indacenes, and indeno[1,2,3-ef]heptalenes with inverted gaps, among which there are several synthetically known examples. In contrast to known inverted gap emitters, we identify the double-bond delocalized structure of their conjugated cores as the necessary condition to achieve the inverted gap. This strategy enables chemical tuning and paves the way for the rational design of polycyclic hydrocarbons with inverted singlet-triplet gaps. These molecules are prospective emitters if their properties can be optimized for use in OLEDs.
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Affiliation(s)
- Marc H Garner
- Laboratory for Computational Molecular Design, Institute of Chemical Sciences and Engineering, École Polytechnique Fedéralé de Lausanne (EPFL) 1015 Lausanne Switzerland
| | - J Terence Blaskovits
- Laboratory for Computational Molecular Design, Institute of Chemical Sciences and Engineering, École Polytechnique Fedéralé de Lausanne (EPFL) 1015 Lausanne Switzerland
| | - Clémence Corminboeuf
- Laboratory for Computational Molecular Design, Institute of Chemical Sciences and Engineering, École Polytechnique Fedéralé de Lausanne (EPFL) 1015 Lausanne Switzerland
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10
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Mizuno Y, Nogata A, Suzuki M, Nakayama KI, Hisaki I, Kishi R, Konishi A, Yasuda M. Synthesis and Characterization of Dibenzothieno[ a, f]pentalenes Enabling Large Antiaromaticity and Moderate Open-Shell Character through a Small Energy Barrier for Bond-Shift Valence Tautomerization. J Am Chem Soc 2023; 145:20595-20609. [PMID: 37695346 DOI: 10.1021/jacs.3c07356] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/12/2023]
Abstract
Experimental and theoretical rationalization of bond-shift valence tautomerization, characterized by double-well potential surfaces, is one of the most challenging topics of study among the rich electronic properties of antiaromatic molecules. Although the pseudo-Jahn-Teller effect (PJTE) is an essential effect to provide attractive characteristics of 4nπ systems, an understanding of the structure-property relationship derived from the PJTE for planar 4nπ electron systems is still in its infancy. Herein, we describe the synthesis and characterization of two regioisomers of the thiophene-fused diareno[a,f]pentalenes 6 and 7. The magnetic and optoelectronic properties characterize these sulfur-doped diareno[a,f]pentalenes as open-shell antiaromatic molecules, in sharp contrast to the closed-shell antiaromatic systems of 3 and 5, in which these main cores consist of the same number of π electrons as 6 and 7. Notably, thiophene-fused 6b and 7b showed pronounced antiaromaticity, the strongest among the previous systems, as well as moderate open-shell characteristics. Our experimental and theoretical investigations concluded that these properties of 6b and 7b are derived from the small energy barrier Ea‡ for the bond-shift valence tautomerization. The energy profile of the single crystal of 6b showed the temperature-dependent structural variations assigned to the dynamic mutual exchange between the two Cs-symmetric structures, which was also supported by changes in the chemical shifts of variable-temperature 1H NMR spectra in the solution phase. Both experimental and computational results revealed the importance of introducing heteroaromatic rings into 4nπ systems for controlling the PJTE and manifesting the antiaromatic and open-shell natures originating from the high-symmetric structure. The findings of this study advance the understanding of antiaromaticity characterized by the PJTE by controlling the energy barrier for bond-shift valence tautomerizations, potentially leading to the rational design of optoelectronic devices based on novel antiaromatic molecules possessing the strong contributions of their high-symmetric geometries.
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Affiliation(s)
- Yusuke Mizuno
- Department of Applied Chemistry, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Akira Nogata
- Department of Applied Chemistry, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Mitsuharu Suzuki
- Department of Applied Chemistry, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Ken-Ichi Nakayama
- Department of Applied Chemistry, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Ichiro Hisaki
- Division of Chemistry, Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyama, Toyonaka, Osaka 560-8531, Japan
| | - Ryohei Kishi
- Department of Materials Engineering Science, Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyama, Toyonaka, Osaka 560-8531, Japan
- Center for Quantum Information and Quantum Biology (QIQB), Osaka University, Toyonaka, Osaka 560-8531, Japan
- Innovative Catalysis Science Division, Institute for Open and Transdisciplinary Research Initiatives (ICS-OTRI), Osaka University, Suita, Osaka 565-0871, Japan
| | - Akihito Konishi
- Department of Applied Chemistry, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan
- Innovative Catalysis Science Division, Institute for Open and Transdisciplinary Research Initiatives (ICS-OTRI), Osaka University, Suita, Osaka 565-0871, Japan
| | - Makoto Yasuda
- Department of Applied Chemistry, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871, Japan
- Innovative Catalysis Science Division, Institute for Open and Transdisciplinary Research Initiatives (ICS-OTRI), Osaka University, Suita, Osaka 565-0871, Japan
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11
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Xu T, Hou X, Han Y, Wei H, Li Z, Chi C. Fused Indacene Dimers. Angew Chem Int Ed Engl 2023; 62:e202304937. [PMID: 37387478 DOI: 10.1002/anie.202304937] [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: 04/07/2023] [Revised: 06/12/2023] [Accepted: 06/28/2023] [Indexed: 07/01/2023]
Abstract
Polycyclic hydrocarbons consisting of two or more directly fused antiaromatic subunits are rare due to their high reactivity. However, it is important to understand how the interactions between the antiaromatic subunits influence the electronic properties of the fused structure. Herein, we present the synthesis of two fused indacene dimer isomers: s-indaceno[2,1-a]-s-indacene (s-ID) and as-indaceno[3,2-b]-as-indacene (as-ID), containing two fused antiaromatic s-indacene or as-indacene units, respectively. Their structures were confirmed by X-ray crystallographic analysis. 1 H NMR/ESR measurements and DFT calculations revealed that both s-ID and as-ID have an open-shell singlet ground state. However, while localized antiaromaticity was observed in s-ID, as-ID showed weak global aromaticity. Moreover, as-ID exhibited a larger diradical character and a smaller singlet-triplet gap than s-ID. All the differences can be attributed to their distinct quinoidal substructures.
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Affiliation(s)
- Tingting Xu
- Department of Chemistry, National University of Singapore, 3 Science drive 3, 117543, Singapore, Singapore
| | - Xudong Hou
- Department of Chemistry, National University of Singapore, 3 Science drive 3, 117543, Singapore, Singapore
| | - Yi Han
- Department of Chemistry, National University of Singapore, 3 Science drive 3, 117543, Singapore, Singapore
| | - Haipeng Wei
- Department of Chemistry, National University of Singapore, 3 Science drive 3, 117543, Singapore, Singapore
| | - Zhengtao Li
- Department of Chemistry, National University of Singapore, 3 Science drive 3, 117543, Singapore, Singapore
| | - Chunyan Chi
- Department of Chemistry, National University of Singapore, 3 Science drive 3, 117543, Singapore, Singapore
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12
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Karas LJ, Jalife S, Viesser RV, Soares JV, Haley MM, Wu JI. Tetra-tert-butyl-s-indacene is a Bond-Localized C 2h Structure and a Challenge for Computational Chemistry. Angew Chem Int Ed Engl 2023; 62:e202307379. [PMID: 37467313 PMCID: PMC10528983 DOI: 10.1002/anie.202307379] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2023] [Revised: 07/18/2023] [Accepted: 07/19/2023] [Indexed: 07/21/2023]
Abstract
Whether tetra-tert-butyl-s-indacene is a symmetric D2h structure or a bond-alternating C2h structure remains a standing puzzle. Close agreement between experimental and computed proton chemical shifts based on minima structures optimized at the M06-2X, ωB97X-D, and M11 levels confirm a bond-localized C2h symmetry, which is consistent with the expected strong antiaromaticity of TtB-s-indacene.
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Affiliation(s)
- Lucas J Karas
- Department of Chemistry, University of Houston, Houston, TX 77204, USA
| | - Said Jalife
- Department of Chemistry, University of Houston, Houston, TX 77204, USA
| | - Renan V Viesser
- Department of Chemistry, University of Houston, Houston, TX 77204, USA
| | - João V Soares
- Department of Chemistry, University of Houston, Houston, TX 77204, USA
| | - Michael M Haley
- Department of Chemistry & Biochemistry and the Materials Science Institute, University of Oregon, Eugene, OR 97403-1253, USA
| | - Judy I Wu
- Department of Chemistry, University of Houston, Houston, TX 77204, USA
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13
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Jana P, Koppayithodi S, Mahato S, Molla S, Bandyopadhyay S. Stable Diradical on the Dimethyldihydropyrene Scaffold. J Phys Chem Lett 2023; 14:7433-7439. [PMID: 37578893 DOI: 10.1021/acs.jpclett.3c01808] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/16/2023]
Abstract
The diradical character in a molecular architecture can be customized primarily in two ways: first, by employing a quinoidal pro-aromatic system with net energy gained by aromatization that compensates for the energy required to generate the diradical species and, second, by employing an antiaromatic system having easily accessible triplet states that impart a diradical character. We have chosen a 14π aromatic framework, Boekelheide's dimethyldihydropyrene, and perturbed its aromaticity through the construction of its quinoidal form. The perturbed aromaticity was evident from the bond alteration in the X-ray diffraction structure, 1H nuclear magnetic resonance chemical shifts, and quantum chemical calculations. The aromaticity was restored as the system underwent a transition to the biradical structure centered on two exocyclic carbons. In addition, upon photoexcitation and without using an external reducing reagent, the diradical could be converted to a radical anion and dianion form easily when dimethylformamide was used as a solvent.
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Affiliation(s)
- Palash Jana
- Department of Chemical Sciences, Indian Institute of Science Education and Research (IISER) Kolkata, Mohanpur, Nadia, West Bengal 741246, India
| | - Sudeep Koppayithodi
- Department of Chemical Sciences, Indian Institute of Science Education and Research (IISER) Kolkata, Mohanpur, Nadia, West Bengal 741246, India
| | - Samyadeb Mahato
- Department of Chemical Sciences, Indian Institute of Science Education and Research (IISER) Kolkata, Mohanpur, Nadia, West Bengal 741246, India
- Department of Chemistry, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada
| | - Sariful Molla
- Department of Chemical Sciences, Indian Institute of Science Education and Research (IISER) Kolkata, Mohanpur, Nadia, West Bengal 741246, India
| | - Subhajit Bandyopadhyay
- Department of Chemical Sciences, Indian Institute of Science Education and Research (IISER) Kolkata, Mohanpur, Nadia, West Bengal 741246, India
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14
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Han Y, Zhu J, Dong S, Eng Y, Tao T, Gopalakrishna TY, Chi C. Bisazapentalene Dication: Global Aromaticity and Open-Shell Singlet Ground State. Org Lett 2023; 25:3380-3385. [PMID: 37162270 DOI: 10.1021/acs.orglett.3c00870] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Antiaromatic moieties fused in polycyclic π-conjugated molecules usually exhibit strong localized antiaromaticiy. Herein, we reported the synthesis and properties of a bisazapentalene dication (BAP2+) obtained from in situ two-electron oxidation of neutral species 8. Noteworthily, it possesses global aromaticity and an open-shell singlet ground state. This study underlines the importance of heteroatoms in determining the delocalization of π-electrons and the aromaticity of molecules in their oxidized states.
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Affiliation(s)
- Yi Han
- Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore 117543, Singapore
| | - Jun Zhu
- Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore 117543, Singapore
| | - Shaoqiang Dong
- Institute of Molecular Aggregation Science, Tianjin University, Tianjin 300072, PR China
| | - Yijie Eng
- Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore 117543, Singapore
| | - Tao Tao
- School of Environmental Science and Engineering, Nanjing University of Information Science & Technology, Nanjing 210044, PR China
| | - Tullimilli Y Gopalakrishna
- Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore 117543, Singapore
| | - Chunyan Chi
- Department of Chemistry, National University of Singapore, 3 Science Drive 3, Singapore 117543, Singapore
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15
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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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16
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Jhang SJ, Pandidurai J, Chu CP, Miyoshi H, Takahara Y, Miki M, Sotome H, Miyasaka H, Chatterjee S, Ozawa R, Ie Y, Hisaki I, Tsai CL, Cheng YJ, Tobe Y. s-Indacene Revisited: Modular Synthesis and Modulation of Structures and Molecular Orbitals of Hexaaryl Derivatives. J Am Chem Soc 2023; 145:4716-4729. [PMID: 36796008 DOI: 10.1021/jacs.2c13159] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/18/2023]
Abstract
Though s-indacene is an intriguing antiaromatic hydrocarbon of 12 π-electrons, it has been underrepresented due to the lack of efficient and versatile methods to prepare stable derivatives. Herein we report a concise and modular synthetic method for hexaaryl-s-indacene derivatives bearing electron-donating/-accepting groups at specific positions to furnish C2h-, D2h-, and C2v-symmetric substitution patterns. We also report the effects of substituents on their molecular structures, frontier molecular orbital (MO) levels, and magnetically induced ring current tropicities. Both theoretical calculations and X-ray structure analyses indicate that the derivatives of the C2h-substitution pattern adopt different C2h structures with significant bond length alternation depending on the electronic property of the substituents. Due to the nonuniform distribution of the frontier MOs, their energy levels are selectively modulated by the electron-donating substituents. This leads to the inversion of the HOMO and HOMO-1 sequences with respect to those of the intrinsic s-indacene as theoretically predicted and experimentally proven by the absorption spectra at visible and near-infrared regions. The NICS values and the 1H NMR chemical shifts of the s-indacene derivatives indicate their weak antiaromaticity. The different tropicities are explained by the modulation of the HOMO and HOMO-1 levels. In addition, for the hexaxylyl derivative, weak fluorescence from the S2 excited state was detected due to the large energy gap between the S1 and S2 states. Notably, an organic field-effect transistor (OFET) fabricated using the hexaxylyl derivative exhibited moderate hole carrier mobility, a result which opens the door for optoelectronic applications of s-indacene derivatives.
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Affiliation(s)
- Shun-Jie Jhang
- Department of Applied Chemistry, National Yang Ming Chiao Tung University, 1001 Ta Hsueh Road, Hsinchu 30010, Taiwan
| | - Jayabalan Pandidurai
- Department of Applied Chemistry, National Yang Ming Chiao Tung University, 1001 Ta Hsueh Road, Hsinchu 30010, Taiwan
| | - Ching-Piao Chu
- Department of Applied Chemistry, National Yang Ming Chiao Tung University, 1001 Ta Hsueh Road, Hsinchu 30010, Taiwan
| | - Hirokazu Miyoshi
- Division of Frontier Materials Science, Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531, Japan
| | - Yuta Takahara
- Division of Frontier Materials Science, Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531, Japan
| | - Masahito Miki
- Division of Frontier Materials Science, Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531, Japan
| | - Hikaru Sotome
- Division of Chemistry, Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531, Japan
| | - Hiroshi Miyasaka
- Division of Chemistry, Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531, Japan
| | - Shreyam Chatterjee
- Nanoscience and Nanotechnology Center, The Institute of Scientific and Industrial Research (SANKEN), Osaka University, Ibaraki, Osaka 567-0047, Japan
| | - Rumi Ozawa
- Nanoscience and Nanotechnology Center, The Institute of Scientific and Industrial Research (SANKEN), Osaka University, Ibaraki, Osaka 567-0047, Japan
| | - Yutaka Ie
- Nanoscience and Nanotechnology Center, The Institute of Scientific and Industrial Research (SANKEN), Osaka University, Ibaraki, Osaka 567-0047, Japan
| | - Ichiro Hisaki
- Division of Chemistry, Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531, Japan
| | - Chia-Lin Tsai
- Department of Applied Chemistry, National Yang Ming Chiao Tung University, 1001 Ta Hsueh Road, Hsinchu 30010, Taiwan
| | - Yen-Ju Cheng
- Department of Applied Chemistry, National Yang Ming Chiao Tung University, 1001 Ta Hsueh Road, Hsinchu 30010, Taiwan
| | - Yoshito Tobe
- Department of Applied Chemistry, National Yang Ming Chiao Tung University, 1001 Ta Hsueh Road, Hsinchu 30010, Taiwan.,Division of Frontier Materials Science, Graduate School of Engineering Science, Osaka University, Toyonaka, Osaka 560-8531, Japan.,Nanoscience and Nanotechnology Center, The Institute of Scientific and Industrial Research (SANKEN), Osaka University, Ibaraki, Osaka 567-0047, Japan
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17
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Xu X, Takebayashi S, Hanayama H, Vasylevskyi S, Onishi T, Ohto T, Tada H, Narita A. 6,6'-Biindeno[1,2- b]anthracene: An Open-Shell Biaryl with High Diradical Character. J Am Chem Soc 2023; 145:3891-3896. [PMID: 36780241 DOI: 10.1021/jacs.2c13890] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/14/2023]
Abstract
We report in situ generation of a 6,6'-biindeno[1,2-b]anthracene (BIA) derivative as an open-shell biaryl with high diradical character, which could be identified by mass spectrometry, NMR spectroscopy, single-crystal X-ray analysis, UV-vis-NIR absorption spectroscopy, and electron paramagnetic resonance (EPR) spectroscopy. Theoretical calculations by various methods and variable-temperature EPR analyses were performed to tackle the elusive ground state of BIA diradical, suggesting a singlet ground state with a nearly degenerate triplet state. These results provide insight into the design of unique open-shell biaryls.
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Affiliation(s)
- Xiushang Xu
- Organic and Carbon Nanomaterials Unit, Okinawa Institute of Science and Technology Graduate University, 1919-1 Tancha, Onna-son, Kunigami-gun, Okinawa 904-0495, Japan
- Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
| | - Satoshi Takebayashi
- Science and Technology Group, Okinawa Institute of Science and Technology Graduate University, 1919-1 Tancha, Onna-son, Kunigami-gun, Okinawa 904-0495, Japan
| | - Hiroki Hanayama
- Organic and Carbon Nanomaterials Unit, Okinawa Institute of Science and Technology Graduate University, 1919-1 Tancha, Onna-son, Kunigami-gun, Okinawa 904-0495, Japan
| | - Serhii Vasylevskyi
- Engineering Section, Research Support Division, Okinawa Institute of Science and Technology Graduate University, 1919-1 Tancha, Onna-son, Kunigami-gun, Okinawa 904-0495, Japan
| | - Takatsugu Onishi
- Organic and Carbon Nanomaterials Unit, Okinawa Institute of Science and Technology Graduate University, 1919-1 Tancha, Onna-son, Kunigami-gun, Okinawa 904-0495, Japan
| | - Tatsuhiko Ohto
- Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyama, Toyonaka, Osaka 560-8531, Japan
- Center for Quantum Information and Quantum Biology, Institute for Open and Transdisciplinary Research Initiatives, Osaka University, 1-3 Machikaneyama, Toyonaka, Osaka 560-8531, Japan
| | - Hirokazu Tada
- Graduate School of Engineering Science, Osaka University, 1-3 Machikaneyama, Toyonaka, Osaka 560-8531, Japan
| | - Akimitsu Narita
- Organic and Carbon Nanomaterials Unit, Okinawa Institute of Science and Technology Graduate University, 1919-1 Tancha, Onna-son, Kunigami-gun, Okinawa 904-0495, Japan
- Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
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18
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Abdurahman A, Wang J, Zhao Y, Li P, Shen L, Peng Q. A Highly Stable Organic Luminescent Diradical. Angew Chem Int Ed Engl 2023; 62:e202300772. [PMID: 36781392 DOI: 10.1002/anie.202300772] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2023] [Revised: 02/11/2023] [Accepted: 02/13/2023] [Indexed: 02/15/2023]
Abstract
It is very challenging to obtain stable room-temperature luminescent open-shell singlet diradicals. Herein we report the first stable Müller's hydrocarbon TTM-PhTTM with luminescent properties. Variable-temperature electron paramagnetic resonance spectroscopy measurements and theoretical calculations show that TTM-PhTTM has an open-shell singlet ground state with a diradical character of 90 %. Because of a small singlet-triplet energy gap, the open-shell singlet ground state can be thermally excited to a triplet state. TTM-PhTTM shows room-temperature deep-red emission in various solutions. Unusually high stability of TTM-PhTTM was also observed owing to effective steric hindrance and spin delocalization. Our results are beneficial to the rational design and discovery of more stable luminescent diradical materials.
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Affiliation(s)
- Alim Abdurahman
- State Key Laboratory of Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, Qianjin Avenue 2699, Changchun, 130012, P. R. China
| | - Jingmin Wang
- Key Laboratory of Flexible Electronics (KLOFE), Institute of Advanced Materials (IAM) & School of Flexible Electronics (Future Technologies), Nanjing Tech University (NanjingTech), 30 South Puzhu Road, Nanjing, 211816, China
| | - Yihan Zhao
- State Key Laboratory of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Qianjin Avenue 2699, Changchun, 130012, P. R. China
| | - Ping Li
- Key Laboratory for Organic Electronics and Information Displays & Institute of Advanced Materials (IAM), National Synergistic Innovation Center for Advanced Materials (SICAM), Nanjing University of Posts & Telecommunications, 9 Wenyuan Road, Nanjing, 210023, P. R. China
| | - Li Shen
- College of Chemical Engineering and Environmental Chemistry, Weifang University, Weifang, 261061, China
| | - Qiming Peng
- Key Laboratory of Flexible Electronics (KLOFE), Institute of Advanced Materials (IAM) & School of Flexible Electronics (Future Technologies), Nanjing Tech University (NanjingTech), 30 South Puzhu Road, Nanjing, 211816, China
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19
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Li Z, Tang Y, Guo J, Zhang J, Deng M, Xiao W, Li F, Yao Y, Xie S, Yang K, Zeng Z. Stair-like narrow N-doped nanographene with unusual diradical character at the topological interface. Chem 2023. [DOI: 10.1016/j.chempr.2023.01.019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/19/2023]
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20
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Bai W, Tsang LY, Wang Y, Li Y, Sung HHY, Williams ID, Jia G. Synthesis and characterization of bi(metallacycloprop-1-ene) complexes. Chem Sci 2022; 14:96-102. [PMID: 36605739 PMCID: PMC9769101 DOI: 10.1039/d2sc05378k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2022] [Accepted: 11/15/2022] [Indexed: 11/18/2022] Open
Abstract
In all previously reported metallacycloprop-1-ene or η2-vinyl complexes, the metal center bears only one vinyl moiety. We have now successfully synthesized and structurally characterized the first complexes bearing two η2-vinyl moieties or spiro bi(metallacycloprop-1-ene) complexes from reactions of alkynes with rhenium phosphine complexes. Computational studies indicate that the metallacycloprop-1-ene rings are aromatic and the complexes represent a rare σ-type spirometalla-aromatic system.
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Affiliation(s)
- Wei Bai
- Department of Chemistry, The Hong Kong University of Science and TechnologyClear Water BayKowloonHong KongP. R. China,State Key Laboratory of Fine Chemicals, Department of Chemistry, School of Chemical Engineering, Dalian University of TechnologyLiaoning 116024P. R. China
| | - Long Yiu Tsang
- Department of Chemistry, The Hong Kong University of Science and TechnologyClear Water BayKowloonHong KongP. R. China
| | - Yilun Wang
- State Key Laboratory of Fine Chemicals, Department of Chemistry, School of Chemical Engineering, Dalian University of TechnologyLiaoning 116024P. R. China,School of Chemical Engineering, Dalian University of TechnologyPanjinLiaoning 124221P. R. China
| | - Yang Li
- State Key Laboratory of Fine Chemicals, Department of Chemistry, School of Chemical Engineering, Dalian University of TechnologyLiaoning 116024P. R. China,School of Chemical Engineering, Dalian University of TechnologyPanjinLiaoning 124221P. R. China
| | - Herman H. Y. Sung
- Department of Chemistry, The Hong Kong University of Science and TechnologyClear Water BayKowloonHong KongP. R. China
| | - Ian D. Williams
- Department of Chemistry, The Hong Kong University of Science and TechnologyClear Water BayKowloonHong KongP. R. China
| | - Guochen Jia
- Department of Chemistry, The Hong Kong University of Science and TechnologyClear Water BayKowloonHong KongP. R. China
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21
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Moles Quintero S, Haley MM, Kertesz M, Casado J. Polycyclic Hydrocarbons from [4n]Annulenes: Correlation versus Hybridization Forces in the Formation of Diradicaloids. Angew Chem Int Ed Engl 2022; 61:e202209138. [PMID: 35986661 PMCID: PMC9826091 DOI: 10.1002/anie.202209138] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2022] [Indexed: 01/11/2023]
Abstract
The conceptual connections between [4n] Hückel antiaromaticity, disjoint orbitals, correlation energy, pro-aromaticity and diradical character for a variety of extended π-conjugated systems, including some salient recent examples of nanographenes and polycyclic aromatic radicals, are provided based on their [4n]annulene peripheries. The realization of such structure-property relationships has led to a beneficial pedagogic exercise establishing design guidelines for diradicaloids. The antiaromatic fingerprint of the [4n]annulene peripheries upon orbital interactions due to internal covalent connectors gives insights into the diradicaloid property of a diversity of π-conjugated molecules that have fascinated chemists recently.
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Affiliation(s)
| | - Michael M. Haley
- Department of Chemistry & Biochemistry and Materials Science InstituteUniversity of OregonEugeneOR 97403-1253USA
| | - Miklos Kertesz
- Department of Chemistry and Institute of Soft MatterGeorgetown UniversityWashingtonDC 20057-1227USA
| | - Juan Casado
- Department of Physical ChemistryUniversity of Málaga29071MálagaSpain
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22
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Quintero SM, Haley MM, Kertesz M, Casado J. Polycyclic Hydrocarbons from [4n]annulenes: Correlation vs. Hybridization Forces in the Formation of Diradicaloids. Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202209138] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Sergio Moles Quintero
- University of Malaga: Universidad de Malaga Department of Physical Chemistry Facultad de CienciasCampus de Teatinos 29071 Málaga SPAIN
| | - Michael M. Haley
- University of Oregon Department of Chemistry & Biochemistry and Materials Science Institute UNITED STATES
| | - Miklos Kertesz
- Georgetown University Department of Chemistry and Institute of Soft Matter SPAIN
| | - Juan Casado
- University of Málaga Dept. of Physical Chemistry Campus de Teatinos s/n 29071 Málaga SPAIN
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23
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24
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Ong A, Tao T, Jiang Q, Han Y, Ou Y, Huang KW, Chi C. Azulene‐Fused Acenes. Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202209286] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Albert Ong
- National University of Singapore Asia Research Institute Department of Chemistry SINGAPORE
| | - Tao Tao
- Nanjing University of Information Science and Technology School of Environmental Science and Engineering CHINA
| | - Qing Jiang
- National University of Singapore Asia Research Institute Department of Chemistry SINGAPORE
| | - Yi Han
- National University of Singapore Asia Research Institute Department of Chemistry SINGAPORE
| | - Yaping Ou
- National University of Singapore Asia Research Institute Department of Chemistry SINGAPORE
| | - Kuo-Wei Huang
- King Abdullah University of Science and Technology KAUST Catalysis Center and Division of Physical Science and Engineering SAUDI ARABIA
| | - Chunyan Chi
- National University of Singapore Department of Chemistry 3 Science Drive 3 117543 Singapore SINGAPORE
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25
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Herzog S, Hinz A, Breher F, Podlech J. Cyclopenta-fused polyaromatic hydrocarbons: synthesis and characterisation of a stable, carbon-centred helical radical. Org Biomol Chem 2022; 20:2873-2880. [PMID: 35315476 DOI: 10.1039/d2ob00172a] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
An air- and moisture-stable helical radical with seven six- and five-membered rings arranged alternately was synthesized by cyclizations in a suitably ortho,ortho'-substituted terphenyl and re-establishment of its conjugation. Mesityl groups at the five-membered rings prevent radical reactions. This cyclopenta-fused polyaromatic hydrocarbon (CP-PAH) was characterized by X-ray crystallographic analysis, EPR and UV/Vis spectroscopy, and by cyclic voltammetry. Further properties and spectra were determined by quantum chemical calculation (spin densities, orbital energies, UV/Vis/NIR and ECD spectra). It turned out that this radical is best described with its radical centre being in the outer five-membered rings, which allows for the largest number of fully intact benzene rings. Its triradical character is rather small and can be neglected. The five-membered rings show significant antiaromatic character, which is highest in the central ring.
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Affiliation(s)
- Stefan Herzog
- Institut für Organische Chemie, Karlsruher Institut für Technologie (KIT), 76131 Karlsruhe, Fritz-Haber-Weg 6, Germany
| | - Alexander Hinz
- Institut für Anorganische Chemie, Karlsruher Institut für Technologie (KIT), 76131 Karlsruhe, Engesserstraße 15, Germany.
| | - Frank Breher
- Institut für Anorganische Chemie, Karlsruher Institut für Technologie (KIT), 76131 Karlsruhe, Engesserstraße 15, Germany.
| | - Joachim Podlech
- Institut für Organische Chemie, Karlsruher Institut für Technologie (KIT), 76131 Karlsruhe, Fritz-Haber-Weg 6, Germany
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Abstract
Parent 2,3:10,11-dibenzoheptazethrene is a singlet diradicaloid polycyclic hydrocarbon in the ground state that did not change its diradical character upon substitution (methyl and triisopropylsilylethynyl). Described herein are the synthesis and characterization of an ethoxy/3,5-(CF3)2C6H3-substituted 2,3:10,11-dibenzoheptazethrene 3 that prefers to retain its p-quinoidal core and shows zero diradical character, as determined by single-crystal analysis and density functional theory calculations. Negative solvatochromism, π-π interactions, Csp2-H···O hydrogen bonding, intramolecular charge transfer, redox amphotericity, and a narrow HOMO-LUMO energy gap make 3 a potential candidate for application in optoelectronics.
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Affiliation(s)
- Priyank Kumar Sharma
- Department of Chemistry, Indian Institute of Technology Ropar, Rupnagar, Punjab 140001, India
| | - Soumyajit Das
- Department of Chemistry, Indian Institute of Technology Ropar, Rupnagar, Punjab 140001, India
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