1
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Kim N, You DK, Kim S, Kim D, Cho K, Lee KM. Influence of Intermolecular Structural Effects on Radiative Efficiency in Xanthene-Based Carboranyl Luminophores. Inorg Chem 2024; 63:15044-15052. [PMID: 39074868 DOI: 10.1021/acs.inorgchem.4c01875] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/31/2024]
Abstract
Two o-carboranes with (i) 9,9-dimethyl-9H-xanthene and (ii) spiro[fluorene-9,9'-xanthene] moieties (XTC and sXTC, respectively) were prepared and characterized. Single X-ray crystallography analysis revealed the presence of intermolecular hydrogen bonds in XTC crystals. Although both compounds did not exhibit emission in tetrahydrofuran solutions at 298 K, intense bluish emission was observed in the solid states and frozen tetrahydrofuran solutions at 77 K. According to the results of theoretical calculations, this emission originated from an intramolecular charge transfer (ICT) transition with the o-carborane moiety. The absolute quantum efficiency (Φem) of the ICT-based emission in the film state equaled 49% for XTC and 20% for sXTC but was as high as 90% for the crystals of both compounds. The crystal structures of XTC and sXTC revealed that the o-carboranyl-appended phenyl plane was orthogonal (85-89°) to the carbon-carbon bonding axis in the o-carborane, indicating the existence of a strong exo-π-interaction, which was identified as the structural basis for the ICT-based transition. These results implied that the intermolecular structural effect of XTC in the randomly aggregated solid state (film) helped maintain the above orthogonality and, hence, the high efficiency from the ICT radiative mechanism. Thus, we concluded that the ICT radiative efficiency of o-carboranyl luminophores in the aggregated solid state can be controlled by specific intermolecular interactions and that the molecular geometric design inducing this feature can be important for developing highly efficient carboranyl luminophores.
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Affiliation(s)
- Namkyun Kim
- Department of Chemistry, Institute for Molecular Science and Fusion Technology, Kangwon National University, Chuncheon, Gangwon 24341, Republic of Korea
| | - Dong Kyun You
- Department of Chemistry, Institute for Molecular Science and Fusion Technology, Kangwon National University, Chuncheon, Gangwon 24341, Republic of Korea
| | - Soyeon Kim
- Department of Chemistry, Institute for Molecular Science and Fusion Technology, Kangwon National University, Chuncheon, Gangwon 24341, Republic of Korea
| | - Dongwook Kim
- Center for Catalytic Hydrocarbon Functionalizations, Institute for Basic Science (IBS), Daejeon 34141, Republic of Korea
| | - Kanghee Cho
- Department of Chemistry and Chemical Engineering, Inha University, Incheon 22212, Republic of Korea
| | - Kang Mun Lee
- Department of Chemistry, Institute for Molecular Science and Fusion Technology, Kangwon National University, Chuncheon, Gangwon 24341, Republic of Korea
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2
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Krebs J, Brändler L, Krummenacher I, Friedrich A, Braunschweig H, Finze M, Curchod BFE, Marder TB. Synthesis, Photophysical and Electronic Properties of a D-π-A Julolidine-Like Pyrenyl-o-Carborane. Chemistry 2024; 30:e202401704. [PMID: 38758081 DOI: 10.1002/chem.202401704] [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: 04/30/2024] [Revised: 05/17/2024] [Accepted: 05/17/2024] [Indexed: 05/18/2024]
Abstract
We synthesized 2-(1-1,2-dicarbadodecaboranyl(12))-6,6,12,12-tetramethyl-7,8,11,12-tetrahydro-6H,10H-phenaleno[1,9-fg]pyrido[3,2,1-ij]quinoline (4), a julolidine-like pyrenyl-o-carborane, with pyrene substituted at the 2,7-positions on the HOMO/LUMO nodal plane. Using solid state molecular structures, photophysical data, cyclic voltammetry, DFT and LR-TDDFT calculations, we compare o-carborane and B(Mes)2 (Mes=2,4,6-Me3C6H2) as acceptor groups. Whereas the π-acceptor strength of B(Mes)2 is sufficient to drop the pyrene LUMO+1 below the LUMO, the carborane does not do this. We confirm the π-donor strength of the julolidine-like moiety, however, which raises the pyrene HOMO-1 above the HOMO. In contrast to the analogous pyrene-2-yl-o-carborane, 2-(1-1,2-dicarbadodecaboranyl(12))-pyrene VI, which exhibits dual fluorescence, because the rate of internal conversion between locally-excited (LE) and charge transfer (CT) (from the pyrene to the carborane) states is faster than the radiative decay rate, leading to a thermodynamic equilibrium between the 2 states, 4 shows only single fluorescence, as the CT state involving the carborane as the acceptor moiety in not kinetically accessible, so a more localized CT emission involving the julolidine-like pyrene moiety is observed.
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Affiliation(s)
- Johannes Krebs
- Institute for Inorganic Chemistry and Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074, Würzburg, Germany
| | - Lisa Brändler
- Institute for Inorganic Chemistry and Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074, Würzburg, Germany
| | - Ivo Krummenacher
- Institute for Inorganic Chemistry and Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074, Würzburg, Germany
| | - Alexandra Friedrich
- Institute for Inorganic Chemistry and Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074, Würzburg, Germany
| | - Holger Braunschweig
- Institute for Inorganic Chemistry and Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074, Würzburg, Germany
| | - Maik Finze
- Institute for Inorganic Chemistry and Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074, Würzburg, Germany
| | - Basile F E Curchod
- Centre for Computational Chemistry, School of Chemistry, Cantock's Close, University of Bristol, Bristol, BS8 1TS, United Kingdom
| | - Todd B Marder
- Institute for Inorganic Chemistry and Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074, Würzburg, Germany
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3
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Zhao X, Zhang X, Li X, Wu L, Ji L. Energy Barriers and Gap Between Two Excited States in a Dual-Emissive Carborane. Chemistry 2024; 30:e202401246. [PMID: 38630894 DOI: 10.1002/chem.202401246] [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: 03/28/2024] [Revised: 04/17/2024] [Accepted: 04/17/2024] [Indexed: 04/19/2024]
Abstract
A thorough understanding of the internal conversion process between excited states is important for the designing of ideal multiple-emissive materials. However, it is hard to experimentally measure both the energy barriers and gaps between the excited states of a compound. For a long time, it is dubious if what was measured is the energy gap or barrier between two excited states. In this paper, we designed 1-(pyren-2'-yl)-9,12-di(p-tolyl)-o-carborane (2), which shows dual-emission in solution. Temperature-dependent fluorescence measurements show that the two emission bands in hexane are corresponding to two different excited states. The ratio of the emission bands is controlled by thermodynamics at higher temperatures and by kinetics at lower temperatures. Thus, the energy barrier and energy gaps between the two excited states of 2 can be experimentally estimated.
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Affiliation(s)
- Xueyuan Zhao
- Frontiers Science Center for Flexible Electronics, Xi'an Institute of Flexible Electronics (IFE) and Xi'an Institute of Biomedical Materials & Engineering, Northwestern Polytechnical University, 127 West Youyi Road, Xi'an, 710072, China
- Key Laboratory of Flexible Electronics of Zhejiang Province, Ningbo Institute of Northwestern Polytechnical University, Ningbo, 315103, China
| | - Xinning Zhang
- Frontiers Science Center for Flexible Electronics, Xi'an Institute of Flexible Electronics (IFE) and Xi'an Institute of Biomedical Materials & Engineering, Northwestern Polytechnical University, 127 West Youyi Road, Xi'an, 710072, China
- Key Laboratory of Flexible Electronics of Zhejiang Province, Ningbo Institute of Northwestern Polytechnical University, Ningbo, 315103, China
| | - Xin Li
- Frontiers Science Center for Flexible Electronics, Xi'an Institute of Flexible Electronics (IFE) and Xi'an Institute of Biomedical Materials & Engineering, Northwestern Polytechnical University, 127 West Youyi Road, Xi'an, 710072, China
- Key Laboratory of Flexible Electronics of Zhejiang Province, Ningbo Institute of Northwestern Polytechnical University, Ningbo, 315103, China
| | - Lin Wu
- Frontiers Science Center for Flexible Electronics, Xi'an Institute of Flexible Electronics (IFE) and Xi'an Institute of Biomedical Materials & Engineering, Northwestern Polytechnical University, 127 West Youyi Road, Xi'an, 710072, China
- Key Laboratory of Flexible Electronics of Zhejiang Province, Ningbo Institute of Northwestern Polytechnical University, Ningbo, 315103, China
| | - Lei Ji
- Frontiers Science Center for Flexible Electronics, Xi'an Institute of Flexible Electronics (IFE) and Xi'an Institute of Biomedical Materials & Engineering, Northwestern Polytechnical University, 127 West Youyi Road, Xi'an, 710072, China
- Key Laboratory of Flexible Electronics of Zhejiang Province, Ningbo Institute of Northwestern Polytechnical University, Ningbo, 315103, China
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4
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Aniés F, Hamilton I, De Castro CSP, Furlan F, Marsh AV, Xu W, Pirela V, Patel A, Pompilio M, Cacialli F, Martín J, Durrant JR, Laquai F, Gasparini N, Bradley DDC, Heeney M. A Conjugated Carboranyl Main Chain Polymer with Aggregation-Induced Emission in the Near-Infrared. J Am Chem Soc 2024; 146:13607-13616. [PMID: 38709316 PMCID: PMC11100012 DOI: 10.1021/jacs.4c03521] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2024] [Revised: 04/23/2024] [Accepted: 04/24/2024] [Indexed: 05/07/2024]
Abstract
Materials exhibiting aggregation-induced emission (AIE) are both highly emissive in the solid state and prompt a strongly red-shifted emission and should therefore pose as good candidates toward emerging near-infrared (NIR) applications of organic semiconductors (OSCs). Despite this, very few AIE materials have been reported with significant emissivity past 700 nm. In this work, we elucidate the potential of ortho-carborane as an AIE-active component in the design of NIR-emitting OSCs. By incorporating ortho-carborane in the backbone of a conjugated polymer, a remarkable solid-state photoluminescence quantum yield of 13.4% is achieved, with a photoluminescence maximum of 734 nm. In contrast, the corresponding para and meta isomers exhibited aggregation-caused quenching. The materials are demonstrated for electronic applications through the fabrication of nondoped polymer light-emitting diodes. Devices employing the ortho isomer achieved nearly pure NIR emission, with 86% of emission at wavelengths longer than 700 nm and an electroluminescence maximum at 761 nm, producing a significant light output of 1.37 W sr-1 m-2.
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Affiliation(s)
- Filip Aniés
- Department
of Chemistry, Centre for Processable Electronics, Molecular Sciences
Research Hub, Imperial College London, 80 Wood Lane, London, W12 0BZ, U.K.
| | - Iain Hamilton
- KAUST
Solar Center, King Abdullah University of
Science and Technology, Thuwal, 23955-6900, Saudi Arabia
| | - Catherine S. P. De Castro
- KAUST
Solar Center, King Abdullah University of
Science and Technology, Thuwal, 23955-6900, Saudi Arabia
| | - Francesco Furlan
- Department
of Chemistry, Centre for Processable Electronics, Molecular Sciences
Research Hub, Imperial College London, 80 Wood Lane, London, W12 0BZ, U.K.
| | - Adam V. Marsh
- KAUST
Solar Center, King Abdullah University of
Science and Technology, Thuwal, 23955-6900, Saudi Arabia
| | - Weidong Xu
- Department
of Chemistry, Centre for Processable Electronics, Molecular Sciences
Research Hub, Imperial College London, 80 Wood Lane, London, W12 0BZ, U.K.
| | - Valentina Pirela
- POLYMAT
University of the Basque Country UPV/EHU, Av. de Tolosa 72, Donostia-San
Sebastián, 20018, Spain
| | - Adil Patel
- Department
of Physics and Astronomy, London Centre for Nanotechnology, University College London, London, WC1E 6BT, U.K.
| | - Michele Pompilio
- Department
of Physics and Astronomy, London Centre for Nanotechnology, University College London, London, WC1E 6BT, U.K.
| | - Franco Cacialli
- Department
of Physics and Astronomy, London Centre for Nanotechnology, University College London, London, WC1E 6BT, U.K.
- Department
of Engineering, Free University of Bozen-Bolzano, Università 5, Bolzano, I-39100, Italy
| | - Jaime Martín
- Universidade
da Coruña, Campus Industrial de Ferrol, CITENI, Esteiro, Ferrol, 15471, Spain
| | - James R. Durrant
- Department
of Chemistry, Centre for Processable Electronics, Molecular Sciences
Research Hub, Imperial College London, 80 Wood Lane, London, W12 0BZ, U.K.
| | - Frédéric Laquai
- KAUST
Solar Center, King Abdullah University of
Science and Technology, Thuwal, 23955-6900, Saudi Arabia
| | - Nicola Gasparini
- Department
of Chemistry, Centre for Processable Electronics, Molecular Sciences
Research Hub, Imperial College London, 80 Wood Lane, London, W12 0BZ, U.K.
| | - Donal D. C. Bradley
- KAUST
Solar Center, King Abdullah University of
Science and Technology, Thuwal, 23955-6900, Saudi Arabia
- NEOM
Education, Research, and Innovation Foundation and University Neom, Al Khuraybah, Tabuk 49643-9136, Saudi Arabia
| | - Martin Heeney
- Department
of Chemistry, Centre for Processable Electronics, Molecular Sciences
Research Hub, Imperial College London, 80 Wood Lane, London, W12 0BZ, U.K.
- KAUST
Solar Center, King Abdullah University of
Science and Technology, Thuwal, 23955-6900, Saudi Arabia
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5
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Lee T, Jang J, Nguyen NNT, Jung J, Lee J, Lee MH. Ortho-Carborane Decorated Multi-Resonance TADF Emitters: Preserving Local Excited State and High Efficiency in OLEDs. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2024; 11:e2309016. [PMID: 38233207 PMCID: PMC10953543 DOI: 10.1002/advs.202309016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/22/2023] [Revised: 12/31/2023] [Indexed: 01/19/2024]
Abstract
A novel class of o-carboranyl luminophores, 2CB-BuDABNA (1) and 3CB-BuDABNA (2) is reported, in which o-carborane moieties are incorporated at the periphery of the B,N-doped multi-resonance thermally activated delayed fluorescence (MR-TADF) core. Both compounds maintain the inherent local emission characteristics of their MR-emitting core, exhibiting intense MR-TADF with high photoluminescence quantum yields in toluene and rigid states. In contrast, the presence of the dark lowest-energy charge transfer state, induced by cage rotation in THF, is suggested to be responsible for emission quenching in a polar solvent. Despite the different arrangement of the cage on the DABNA core, both 1 and 2 show red-shifted emissions compared to the parent compound BuDABNA (3). By utilizing 1 as the emitter, high-efficiency blue organic light-emitting diodes (OLEDs) are achieved with a remarkable maximum external quantum efficiency of 25%, representing the highest reported efficiency for OLEDs employing an o-carboranyl luminophore as the emitter.
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Affiliation(s)
- Taehwan Lee
- Department of ChemistryUniversity of UlsanUlsan44610Republic of Korea
| | - Jee‐Hun Jang
- Department of Materials Science and Engineering and 3D Convergence CenterInha UniversityIncheon22212Republic of Korea
| | | | - Jaehoon Jung
- Department of ChemistryUniversity of UlsanUlsan44610Republic of Korea
| | - Jeong‐Hwan Lee
- Department of Materials Science and Engineering and 3D Convergence CenterInha UniversityIncheon22212Republic of Korea
| | - Min Hyung Lee
- Department of ChemistryUniversity of UlsanUlsan44610Republic of Korea
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6
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You DK, Kim M, Kim D, Kim N, Lee KM. Improvement in Radiative Efficiency Via Intramolecular Charge Transfer in ortho-Carboranyl Luminophores Modified with Functionalized Biphenyls. Inorg Chem 2023. [PMID: 37311712 DOI: 10.1021/acs.inorgchem.3c01242] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
In this study, we found that the electronic effects of the functional groups on aromatic units attached to o-carboranyl species can enhance the efficiency of intramolecular charge transfer (ICT)-based radiative decay processes. Six o-carboranyl-based luminophores having attached functionalized biphenyl groups with CF3, F, H, CH3, C(CH3)3, and OCH3 substituents were prepared and fully characterized by multinuclear magnetic resonance spectroscopy. In addition, their molecular structures were determined by single-crystal X-ray diffractometry, which revealed that the distortion of the biphenyl rings and the geometries around the o-carborane cages were similar. All compounds exhibited ICT-based emissions in the rigid state (solution at 77 K and film). Intriguingly, the quantum efficiencies (Φem) of five compounds (that of the group with CF3 could not be measured because of its extremely weak emissions) in the film state increased gradually as the electron-donating power of the terminal functional group modifying the biphenyl moiety increased. Furthermore, the nonradiative decay constants (knr) for the group with OCH3 were estimated to be one-tenth of those for the group with F, whereas the radiative decay constants (kr) for the five compounds were similar. The dipole moments (μ) calculated for the optimized first excited state (S1) structures gradually increased, from that of the group with CF3 to that of the group with OCH3, implying that the inhomogeneity of the molecular charge distribution was enhanced by electron donation. The electron-rich environment formed as a result of electron donation led to efficient charge transfer to the excited state. Both experimental and theoretical findings revealed that the electronic environment of the aromatic moiety in o-carboranyl luminophores can be controlled to accelerate or interrupt the ICT process in the radiative decay of excited states.
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Affiliation(s)
- Dong Kyun You
- Department of Chemistry, Institute for Molecular Science and Fusion Technology, Kangwon National University, Chuncheon, Gangwon 24341, Republic of Korea
| | - Mingi Kim
- Department of Chemistry, Institute for Molecular Science and Fusion Technology, Kangwon National University, Chuncheon, Gangwon 24341, Republic of Korea
| | - Dongwook Kim
- Center for Catalytic Hydrocarbon Functionalizations, Institute for Basic Science (IBS), Daejeon 34141, Republic of Korea
| | - Namkyun Kim
- Department of Chemistry, Institute for Molecular Science and Fusion Technology, Kangwon National University, Chuncheon, Gangwon 24341, Republic of Korea
| | - Kang Mun Lee
- Department of Chemistry, Institute for Molecular Science and Fusion Technology, Kangwon National University, Chuncheon, Gangwon 24341, Republic of Korea
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7
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Kahraman G, Durçak B, Arsu N, Hey-Hawkins E, Eren T. Photodimerization of anthracene- and carborane-bearing polymers obtained by ring opening metathesis polymerization. Eur Polym J 2023. [DOI: 10.1016/j.eurpolymj.2023.111946] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/08/2023]
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8
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Ochi J, Tanaka K, Chujo Y. Investigation of the Substitution Site Effect on o-Carborane-Based Chromophores by Anthracene Introduction at the B(3) Position. BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 2023. [DOI: 10.1246/bcsj.20220310] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/12/2023]
Affiliation(s)
- Junki Ochi
- Department of Polymer Chemistry, Graduate School of Engineering, Kyoto University, Katsura, Nishikyo-ku, Kyoto 615-8510, Japan
| | - Kazuo Tanaka
- Department of Polymer Chemistry, Graduate School of Engineering, Kyoto University, Katsura, Nishikyo-ku, Kyoto 615-8510, Japan
| | - Yoshiki Chujo
- Department of Polymer Chemistry, Graduate School of Engineering, Kyoto University, Katsura, Nishikyo-ku, Kyoto 615-8510, Japan
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9
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Relationship between the Molecular Geometry and the Radiative Efficiency in Naphthyl-Based Bis-Ortho-Carboranyl Luminophores. MOLECULES (BASEL, SWITZERLAND) 2022; 27:molecules27196565. [PMID: 36235102 PMCID: PMC9572229 DOI: 10.3390/molecules27196565] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/05/2022] [Revised: 09/26/2022] [Accepted: 09/28/2022] [Indexed: 11/05/2022]
Abstract
The efficiency of intramolecular charge transfer (ICT)-based emission on π-aromatic-group-appended closo-ortho-carboranyl luminophores is known to be affected by structural fluctuations and molecular geometry, but investigation of this relationship has been in progress to date. In this study, four naphthyl-based bis-o-carboranyl compounds, in which hydrogen (15CH and 26CH) or trimethysilyl groups (15CS and 26CS) were appended at the o-carborane cage, were synthesized and fully characterized. All the compounds barely displayed an emissive trace in solution at 298 K; however, 15CH and 26CH distinctly exhibited a dual emissive pattern in rigid states (in solution at 77 K and in films), attributed to locally excited (LE) and ICT-based emission, while 15CS and 26CS showed strong ICT-based greenish emission. Intriguingly, the molecular structures of the four compounds, analyzed by single X-ray crystallography, showed that the C-C bond axis of the o-carborane cage in the trimethysilyl group-appended compounds 15CS and 26CS were more orthogonal to the plane of the appended naphthyl group than those in 15CH and 26CH. These features indicate that 15CS and 26CS present an efficient ICT transition based on strong exo-π-interaction, resulting in a higher quantum efficiency (Φem) for ICT-based radiative decay than those of 15CH and 26CH. Moreover, the 26CS structure revealed most orthogonal geometry, resulting in the highest Φem and lowest knr values for the ICT-based emission. Consequently, all the findings verified that efficient ICT-based radiative decay of aromatic group-appended o-carboranyl luminophores could be achieved by the formation of a specific geometry between the o-carborane cage and the aromatic plane.
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10
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Kim M, Ryu CH, You DK, Hong JH, Lee KM. Crucial Factors Regulating Intramolecular Charge-Transfer-Based Radiative Efficiency in ortho-Carboranyl Luminophores: Planarity between Substituted Biphenyl Rings. ACS OMEGA 2022; 7:24027-24039. [PMID: 35847313 PMCID: PMC9281304 DOI: 10.1021/acsomega.2c03344] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
o-Carboranyl compounds contain specific geometries, ranging from planar to orthogonally distorted biphenyl rings. Herein, 13 o-carboranyl compounds, 1HF-13PP, were synthesized and fully characterized to determine the impact of structural formation of the aromatic group appended with the o-carborane to estimate the efficiency of their radiative decay process. All the compounds exhibited significant intramolecular charge transfer (ICT)-based emission in the crystalline state at 298 K. Remarkably, increasing the distorted dihedral angles between biphenyl rings gradually decreased the emission efficiencies. Furthermore, their radiative decay constants decreased linearly with increasing dihedral angles, which demonstrated the inversely proportional relationship between these two factors. These findings distinctly suggest that the planar or distorted geometry of substituted aryl groups can strongly affect the efficiency of the ICT-based radiative process in o-carboranyl luminophores.
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11
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Tahaoğlu D, Usta H, Alkan F. Revisiting the Role of Charge Transfer in the Emission Properties of Carborane-Fluorophore Systems: A TDDFT Investigation. J Phys Chem A 2022; 126:4199-4210. [PMID: 35658432 PMCID: PMC9272399 DOI: 10.1021/acs.jpca.2c02435] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Abstract
In this study, we performed a detailed investigation of the S1 potential energy surface (PES) of o-carborane-anthracene (o-CB-Ant) with respect to the C-C bond length on o-CB and the dihedral angle between o-CB and Ant moieties. The effects of different substituents (F, Cl, CN, and OH) on carbon- or boron-substituted o-CB, along with a π-extended acene-based fluorophore, pentacene, on the nature and energetics of S1 → S0 transitions are evaluated. Our results show the presence of a non-emissive S1 state with an almost pure charge transfer (CT) character for all systems as a result of significant C-C bond elongation (C-C = 2.50-2.56 Å) on o-CB. In the case of unsubstituted o-CB-Ant, the adiabatic energy of this CT state corresponds to the global minimum on the S1 PES, which suggests that the CT state could be involved in emission quenching. Despite large deformations on the o-CB geometry, predicted energy barriers are quite reasonable (0.3-0.4 eV), and the C-C bond elongation can even occur without a noticeable energy penalty for certain conformations. With substitution, it is shown that the dark CT state becomes even more energetically favorable when the substituent shows -M effects (e.g., -CN), whereas substituents showing +M effects (e.g., -OH) can result in an energy increase for the CT state, especially for partially stretched C-C bond lengths. It is also shown that the relative energy of the CT state on the PES depends strongly on the LUMO level of the fluorophore as this state is found to be energetically less favorable compared to other conformations when anthracene is replaced with π-extended pentacene. To our knowledge, this study shows a unique example of a detailed theoretical analysis on the PES of the S1 state in o-CB-fluorophore systems with respect to substituents or fluorophore energy levels. Our findings could guide future experimental work in emissive o-CB-fluorophore systems and their sensing/optoelectronic applications.
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Affiliation(s)
- Duygu Tahaoğlu
- Department of Nanotechnology Engineering, Abdullah Gül University, Kayseri 38080, Turkey
| | - Hakan Usta
- Department of Nanotechnology Engineering, Abdullah Gül University, Kayseri 38080, Turkey
| | - Fahri Alkan
- Department of Nanotechnology Engineering, Abdullah Gül University, Kayseri 38080, Turkey
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12
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Ji L, Riese S, Schmiedel A, Holzapfel M, Fest M, Nitsch J, Curchod BFE, Friedrich A, Wu L, Al Mamari HH, Hammer S, Pflaum J, Fox MA, Tozer DJ, Finze M, Lambert C, Marder TB. Thermodynamic equilibrium between locally excited and charge-transfer states through thermally activated charge transfer in 1-(pyren-2'-yl)- o-carborane. Chem Sci 2022; 13:5205-5219. [PMID: 35655553 PMCID: PMC9093154 DOI: 10.1039/d1sc06867a] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Accepted: 03/24/2022] [Indexed: 02/02/2023] Open
Abstract
Reversible conversion between excited-states plays an important role in many photophysical phenomena. Using 1-(pyren-2'-yl)-o-carborane as a model, we studied the photoinduced reversible charge-transfer (CT) process and the thermodynamic equilibrium between the locally-excited (LE) state and CT state, by combining steady state, time-resolved, and temperature-dependent fluorescence spectroscopy, fs- and ns-transient absorption, and DFT and LR-TDDFT calculations. Our results show that the energy gaps and energy barriers between the LE, CT, and a non-emissive 'mixed' state of 1-(pyren-2'-yl)-o-carborane are very small, and all three excited states are accessible at room temperature. The internal-conversion and reverse internal-conversion between LE and CT states are significantly faster than the radiative decay, and the two states have the same lifetimes and are in thermodynamic equilibrium.
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Affiliation(s)
- Lei Ji
- Frontiers Science Center for Flexible Electronics, Xi'an Institute of Flexible Electronics (IFE), Northwestern Polytechnical University 127 West Youyi Road Xi'an Shaanxi China .,Institut für Anorganische Chemie and Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Germany
| | - Stefan Riese
- Institut für Organische Chemie, Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Germany
| | - Alexander Schmiedel
- Institut für Organische Chemie, Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Germany
| | - Marco Holzapfel
- Institut für Organische Chemie, Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Germany
| | - Maximillian Fest
- Institut für Anorganische Chemie and Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Germany
| | - Jörn Nitsch
- Institut für Anorganische Chemie and Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Germany
| | - Basile F E Curchod
- Department of Chemistry, University of Durham South Road Durham DH1 3LE UK
| | - Alexandra Friedrich
- Institut für Anorganische Chemie and Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Germany
| | - Lin Wu
- Frontiers Science Center for Flexible Electronics, Xi'an Institute of Flexible Electronics (IFE), Northwestern Polytechnical University 127 West Youyi Road Xi'an Shaanxi China
| | - Hamad H Al Mamari
- Institut für Anorganische Chemie and Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Germany .,Department of Chemistry, College of Science, Sultan Qaboos University PO Box 36, Al Khoudh 123 Muscat Sultanate of Oman
| | - Sebastian Hammer
- Experimentelle Physik VI, Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Germany
| | - Jens Pflaum
- Experimentelle Physik VI, Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Germany
| | - Mark A Fox
- Department of Chemistry, University of Durham South Road Durham DH1 3LE UK
| | - David J Tozer
- Department of Chemistry, University of Durham South Road Durham DH1 3LE UK
| | - Maik Finze
- Institut für Anorganische Chemie and Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Germany
| | - Christoph Lambert
- Institut für Organische Chemie, Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Germany
| | - Todd B Marder
- Institut für Anorganische Chemie and Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Germany
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13
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Ryu CH, Lee SH, Kim M, Lee KM. Geometric structural insights for enhanced radiative efficiency: Spiro[fluorene–carbazole]‐based
ortho
‐carboranyl
luminophores. B KOREAN CHEM SOC 2022. [DOI: 10.1002/bkcs.12540] [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)
- Chan Hee Ryu
- Department of Chemistry, Institute for Molecular Science and Fusion Technology Kangwon National University Chuncheon Gangwon Republic of Korea
| | - Seok Ho Lee
- Department of Chemistry, Institute for Molecular Science and Fusion Technology Kangwon National University Chuncheon Gangwon Republic of Korea
| | - Mingi Kim
- Department of Chemistry, Institute for Molecular Science and Fusion Technology Kangwon National University Chuncheon Gangwon Republic of Korea
| | - Kang Mun Lee
- Department of Chemistry, Institute for Molecular Science and Fusion Technology Kangwon National University Chuncheon Gangwon Republic of Korea
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14
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Ochi J, Yuhara K, Tanaka K, Chujo Y. Controlling the Dual-Emission Character of Aryl-Modified o-Carboranes by Intramolecular CH⋅⋅⋅O Interaction Sites. Chemistry 2022; 28:e202200155. [PMID: 35170101 DOI: 10.1002/chem.202200155] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2022] [Indexed: 01/18/2023]
Abstract
It is still challenging to realize a dual-emission system, in which two luminescent bands simultaneously appear by photoexcitation, in solid with organic dyes due to the difficulty in regulation of electronic properties in the excited state and concentration quenching. o-Carborane is known to be a versatile platform for constructing solid-state emitters since the sphere boron cluster is favorable for suppressing intermolecular interactions and subsequently concentration quenching. Here, we show solid-state dual-emissive o-carborane derivatives. We prepared 4 types of o-carborane derivatives and found dual-emission behaviors both in solution and solid states. By regulating the rotation at the o-carborane unit with the intramolecular Ccage H⋅⋅⋅O interaction, the dual-emission intensity ratios were changed. Finally, it was demonstrated that the overall photoluminescence spectra can be estimated using the binding energy of intramolecular interactions.
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Affiliation(s)
- Junki Ochi
- Department of Polymer Chemistry, Graduate School of Engineering, Kyoto University Katsura, Nishikyo-ku, Kyoto, 615-8510, Japan
| | - Kazuhiro Yuhara
- Department of Polymer Chemistry, Graduate School of Engineering, Kyoto University Katsura, Nishikyo-ku, Kyoto, 615-8510, Japan
| | - Kazuo Tanaka
- Department of Polymer Chemistry, Graduate School of Engineering, Kyoto University Katsura, Nishikyo-ku, Kyoto, 615-8510, Japan
| | - Yoshiki Chujo
- Department of Polymer Chemistry, Graduate School of Engineering, Kyoto University Katsura, Nishikyo-ku, Kyoto, 615-8510, Japan
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15
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Sinha S, Kelemen Z, Hümpfner E, Ratera I, Malval JP, Jurado JP, Viñas C, Teixidor F, Núñez R. o-Carborane-based fluorophores as efficient luminescent systems both as solids and as water-dispersible nanoparticles. Chem Commun (Camb) 2022; 58:4016-4019. [PMID: 35266927 DOI: 10.1039/d1cc07211k] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
A set of o-carborane-appended π-conjugated fluorophores and their light-emitting properties in the solid state are reported. The aggregation-induced emission enhancement (AIEE) exhibited for one of the fluorenyl derivatives paved the way to successfully preparing o-carborane-containing organic nanoparticles (NPs) homogeneously dispersed in aqueous media that maintain their luminescence properties. Notably, NPs processed as thin films also show high fluorescence efficiency, suggesting potential optical and optoelectronic applications.
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Affiliation(s)
- Sohini Sinha
- Institut de Ciència de Materials de Barcelona (ICMAB-CSIC), Campus U.A.B., 08193, Bellaterra, Barcelona, Spain.
| | - Zsolt Kelemen
- Department of Inorganic and Analytical Chemistry, Budapest University of Technology and Economics, Mũegyetem Rkp 3, H-1111 Budapest, Hungary
| | - Evelyn Hümpfner
- Department of Inorganic and Analytical Chemistry, Budapest University of Technology and Economics, Mũegyetem Rkp 3, H-1111 Budapest, Hungary
| | - Imma Ratera
- Institut de Ciència de Materials de Barcelona (ICMAB-CSIC), Campus U.A.B., 08193, Bellaterra, Barcelona, Spain. .,CIBER de Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN), 28029 Madrid, Spain
| | - Jean-Pierre Malval
- Université de Haute-Alsace, Institut de Science des Matériaux de Mulhouse (CNRS-UMR7361), 15 rue Jean Starcky BP 2488, 68057 Mulhouse, France
| | - José Piers Jurado
- Institut de Ciència de Materials de Barcelona (ICMAB-CSIC), Campus U.A.B., 08193, Bellaterra, Barcelona, Spain.
| | - Clara Viñas
- Institut de Ciència de Materials de Barcelona (ICMAB-CSIC), Campus U.A.B., 08193, Bellaterra, Barcelona, Spain.
| | - Francesc Teixidor
- Institut de Ciència de Materials de Barcelona (ICMAB-CSIC), Campus U.A.B., 08193, Bellaterra, Barcelona, Spain.
| | - Rosario Núñez
- Institut de Ciència de Materials de Barcelona (ICMAB-CSIC), Campus U.A.B., 08193, Bellaterra, Barcelona, Spain.
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16
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Im S, Ryu CH, Kim M, You DK, Yi S, Lee W, Lee KM. Effects of molecular geometry on the efficiency of intramolecular charge transfer-based luminescence in o-carboranyl-substituted 1H-phenanthro[9,10-d]imidazoles. Inorg Chem Front 2022. [DOI: 10.1039/d1qi01405f] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The distinct difference in solid-state emission efficiency between 1H-phenanthro[9,10-d]imidazole–o-carboranyl luminophores showed that the geometric orientation is a key factor for controlling intramolecular charge transfer-based radiative decay.
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Affiliation(s)
- Sehee Im
- Department of Chemistry, Institute for Molecular Science and Fusion Technology, Kangwon National University, Chuncheon, Gangwon 24341, Republic of Korea
| | - Chan Hee Ryu
- Department of Chemistry, Institute for Molecular Science and Fusion Technology, Kangwon National University, Chuncheon, Gangwon 24341, Republic of Korea
| | - Mingi Kim
- Department of Chemistry, Institute for Molecular Science and Fusion Technology, Kangwon National University, Chuncheon, Gangwon 24341, Republic of Korea
| | - Dong Kyun You
- Department of Chemistry, Institute for Molecular Science and Fusion Technology, Kangwon National University, Chuncheon, Gangwon 24341, Republic of Korea
| | - Sanghee Yi
- Department of Chemistry, Institute for Molecular Science and Fusion Technology, Kangwon National University, Chuncheon, Gangwon 24341, Republic of Korea
| | - Wonchul Lee
- Department of Chemistry, Institute for Molecular Science and Fusion Technology, Kangwon National University, Chuncheon, Gangwon 24341, Republic of Korea
| | - Kang Mun Lee
- Department of Chemistry, Institute for Molecular Science and Fusion Technology, Kangwon National University, Chuncheon, Gangwon 24341, Republic of Korea
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17
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Li Q, Shi C, Huang M, Zhang X, Sun F, Zheng Y, Yan H, Yang C, Yuan A. Three types of charged ligand-based neutral phosphorescent iridium(III) complexes featuring nido-carborane: synthesis, structures, and solution processed organic light-emitting diode applications. Dalton Trans 2021; 50:16304-16310. [PMID: 34730578 DOI: 10.1039/d1dt02990h] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
In view of the fact that coordination configurations and special functional groups are both important for the optical properties of phosphorescent iridium complex materials, we have prepared a novel family of three types of charged ligand (0, -1, and -2) based neutral phosphorescent iridium(III) complexes (Ir1-Ir4) featuring nido-carborane. Single crystal structures indicate that complexes (Ir2, Ir3 and Ir4) with nido-carborane as a functional group at different substitution sites all show a trans-C^C configuration between dianionic (-2) and monoanionic (-1) ligands, which are different from the trans-N^C configuration in complex Ir1 with nido-carborane as a coordination skeleton, which has an interesting Ir-B coordination bond. Notably, Ir2, Ir3 and Ir4 all show obvious yellow light emission, while Ir1 does not emit light either in solution or in the solid state. DFT calculations demonstrate that complexes Ir2, Ir3 and Ir4 exhibit an unusual ligand-to-metal charge transfer (LMCT) excited state character due to the strong electron-donating character of nido-carborane. Considering its better solubility and luminescence properties, Ir3 was successfully applied in solution-processed organic light-emitting diodes and an effective yellow emission was achieved. This work provides a new strategy for the investigation of three types of charged ligand (0, -1, and -2) based phosphorescent iridium complex materials by constructing new dianionic ligands with nido-carborane.
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Affiliation(s)
- Qiuxia Li
- School of Environmental and Chemical Engineering, Jiangsu University of Science and Technology, Zhenjiang 212003, P. R. China.
| | - Chao Shi
- School of Environmental and Chemical Engineering, Jiangsu University of Science and Technology, Zhenjiang 212003, P. R. China.
| | - Manli Huang
- College of Materials Science and Engineering, Shenzhen University, Shenzhen 518060, P. R. China.
| | - Xinghua Zhang
- School of Environmental and Chemical Engineering, Jiangsu University of Science and Technology, Zhenjiang 212003, P. R. China.
| | - Fangxiang Sun
- State Key Laboratory of Coordination Chemistry, Nanjing University, Nanjing 210093, P. R. China.
| | - Ying Zheng
- School of Environmental and Chemical Engineering, Jiangsu University of Science and Technology, Zhenjiang 212003, P. R. China.
| | - Hong Yan
- State Key Laboratory of Coordination Chemistry, Nanjing University, Nanjing 210093, P. R. China.
| | - Chuluo Yang
- College of Materials Science and Engineering, Shenzhen University, Shenzhen 518060, P. R. China.
| | - Aihua Yuan
- School of Environmental and Chemical Engineering, Jiangsu University of Science and Technology, Zhenjiang 212003, P. R. China.
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18
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Ryu CH, Lee SH, Yi S, Hong JH, Im S, Lee KM. Naphthyl‐ and Quinoline‐Appended
o
‐Carboranyl Luminophores: Intramolecular Charge Transfer‐Based Radiative Decay Controlled by Structural Geometry around C−C Bond Axis. Eur J Inorg Chem 2021. [DOI: 10.1002/ejic.202100768] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Chan Hee Ryu
- Department of Chemistry Institute for Molecular Science and Fusion Technology Kangwon National University Chuncheon, Gangwon 24341 Republic of Korea
| | - Seok Ho Lee
- Department of Chemistry Institute for Molecular Science and Fusion Technology Kangwon National University Chuncheon, Gangwon 24341 Republic of Korea
| | - Sanghee Yi
- Department of Chemistry Institute for Molecular Science and Fusion Technology Kangwon National University Chuncheon, Gangwon 24341 Republic of Korea
| | - Ju Hyun Hong
- Department of Chemistry Institute for Molecular Science and Fusion Technology Kangwon National University Chuncheon, Gangwon 24341 Republic of Korea
| | - Sehee Im
- Department of Chemistry Institute for Molecular Science and Fusion Technology Kangwon National University Chuncheon, Gangwon 24341 Republic of Korea
| | - Kang Mun Lee
- Department of Chemistry Institute for Molecular Science and Fusion Technology Kangwon National University Chuncheon, Gangwon 24341 Republic of Korea
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19
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Li C, Aldred MP, Harder RA, Chen Y, Yufit DS, Zhu MQ, Fox MA. Carborane photochromism: a fatigue resistant carborane switch. Chem Commun (Camb) 2021; 57:9466-9469. [PMID: 34528961 DOI: 10.1039/d1cc03248h] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
A dithienylethene molecule involving carborane clusters shows remarkable fatigue resistance and high contrast visual colour changes when irradiated with alternating ultraviolet and visible light. The fluorescence of this assembly can be switched on and off when irradiated in the solid state but not in the solution state.
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Affiliation(s)
- Chong Li
- Wuhan National Laboratory for Optoelectronics, School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
| | - Matthew P Aldred
- Wuhan National Laboratory for Optoelectronics, School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
| | - Rachel A Harder
- Department of Chemistry, Durham University, Lower Mountjoy, Stockton Road, Durham, DH1 3LE, UK
| | - Ying Chen
- Wuhan National Laboratory for Optoelectronics, School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
| | - Dmitry S Yufit
- Department of Chemistry, Durham University, Lower Mountjoy, Stockton Road, Durham, DH1 3LE, UK
| | - Ming-Qiang Zhu
- Wuhan National Laboratory for Optoelectronics, School of Optical and Electronic Information, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
| | - Mark A Fox
- Department of Chemistry, Durham University, Lower Mountjoy, Stockton Road, Durham, DH1 3LE, UK
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20
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Lee SH, Mun MS, Kim M, Lee JH, Hwang H, Lee W, Lee KM. Alteration of intramolecular electronic transition via deboronation of carbazole-based o-carboranyl compound and intriguing 'turn-on' emissive variation. RSC Adv 2021; 11:24057-24064. [PMID: 35479040 PMCID: PMC9036662 DOI: 10.1039/d1ra03716a] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2021] [Accepted: 07/05/2021] [Indexed: 01/10/2023] Open
Abstract
The conversion of closo-o-carborane-containing compounds to the nido-o-species via deboronation causes photophysical changes that could be used for sensing applications. 9-Methyl-9H-carbazole-based closo- (closo-Cz) and nido-o-carboranyl (nido-Cz) compounds were prepared and fully characterised by multinuclear NMR spectroscopy and elemental analysis, and the solid-state molecular structure of closo-Cz was analysed by X-ray crystallography. Although the closo-compound exhibited an emissive pattern centred at λ em = ca. 530 nm in the rigid state only (in THF at 77 K and as a film), nido-Cz demonstrated intense emission in the near-UV region (λ em = ca. 380 nm) in both solution and film states at 298 K. The positive solvatochromic effect of nido-Cz and the results of theoretical calculations for both the o-carboranyl compounds supported that these emissive features originate from intramolecular charge transfer (ICT) corresponding to the o-carborane. Furthermore, the calculations verified that the electronic role of the o-carboranyl unit changed from acceptor to donor upon deboronation from closo-Cz to nido-Cz. Investigations of the radiative decay mechanisms of closo-Cz and nido-Cz according to their quantum efficiencies (Φ em) and decay lifetimes (τ obs) suggested that the ICT-based radiative decays of closo-Cz and nido-Cz readily occur in the film (solid) and solution state, respectively. These observations implied that the emission of closo-Cz in the solution state could be drastically enhanced by deboronation to nido-Cz upon exposure to an increasing concentration of fluoride anions. Indeed, turn-on emissive features in an aqueous solution were observed upon deboronation, strongly suggesting the potential of closo-Cz as a turn-on and visually detectable chemodosimeter for fluoride ion sensing.
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Affiliation(s)
- Seok Ho Lee
- Department of Chemistry, Institute for Molecular Science and Fusion Technology, Kangwon National University Chuncheon Gangwon 24341 Republic of Korea
| | - Min Sik Mun
- Department of Chemistry, Institute for Molecular Science and Fusion Technology, Kangwon National University Chuncheon Gangwon 24341 Republic of Korea
| | - Mingi Kim
- Department of Chemistry, Institute for Molecular Science and Fusion Technology, Kangwon National University Chuncheon Gangwon 24341 Republic of Korea
| | - Ji Hye Lee
- Department of Chemistry, Institute for Molecular Science and Fusion Technology, Kangwon National University Chuncheon Gangwon 24341 Republic of Korea
| | - Hyonseok Hwang
- Department of Chemistry, Institute for Molecular Science and Fusion Technology, Kangwon National University Chuncheon Gangwon 24341 Republic of Korea
| | - Wonchul Lee
- Department of Chemistry, Institute for Molecular Science and Fusion Technology, Kangwon National University Chuncheon Gangwon 24341 Republic of Korea
| | - Kang Mun Lee
- Department of Chemistry, Institute for Molecular Science and Fusion Technology, Kangwon National University Chuncheon Gangwon 24341 Republic of Korea
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21
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Krebs J, Haehnel M, Krummenacher I, Friedrich A, Braunschweig H, Finze M, Ji L, Marder TB. Synthesis and Structure of an o-Carboranyl-Substituted Three-Coordinate Borane Radical Anion. Chemistry 2021; 27:8159-8167. [PMID: 33769625 PMCID: PMC8252506 DOI: 10.1002/chem.202100938] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2021] [Indexed: 12/14/2022]
Abstract
Bis(1-(4-tolyl)-carboran-2-yl)-(4-tolyl)-borane [(1-(4-MeC6 H4 )-closo-1,2-C2 B10 H10 -2-)2 (4-MeC6 H4 )B] (1), a new bis(o-carboranyl)-(R)-borane was synthesised by lithiation of the o-carboranyl precursor and subsequent salt metathesis reaction with (4-tolyl)BBr2 . Cyclic voltammetry experiments on 1 show multiple distinct reduction events with a one-electron first reduction. In a selective reduction experiment the corresponding paramagnetic radical anion 1.- was isolated and characterized. Single-crystal structure analyses allow an in-depth comparison of 1, 1.- , their calculated geometries, and the S1 excited state of 1. Photophysical studies of 1 show a charge transfer (CT) emission with low quantum yield in solution but a strong increase in the solid state. TD-DFT calculations were used to identify transition-relevant orbitals.
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Affiliation(s)
- Johannes Krebs
- Institute for Inorganic ChemistryInstitute for Sustainable Chemistry & Catalysis with BoronJulius-Maximilians-Universität WürzburgAm Hubland97074WürzburgGermany
| | - Martin Haehnel
- Institute for Inorganic ChemistryInstitute for Sustainable Chemistry & Catalysis with BoronJulius-Maximilians-Universität WürzburgAm Hubland97074WürzburgGermany
| | - Ivo Krummenacher
- Institute for Inorganic ChemistryInstitute for Sustainable Chemistry & Catalysis with BoronJulius-Maximilians-Universität WürzburgAm Hubland97074WürzburgGermany
| | - Alexandra Friedrich
- Institute for Inorganic ChemistryInstitute for Sustainable Chemistry & Catalysis with BoronJulius-Maximilians-Universität WürzburgAm Hubland97074WürzburgGermany
| | - Holger Braunschweig
- Institute for Inorganic ChemistryInstitute for Sustainable Chemistry & Catalysis with BoronJulius-Maximilians-Universität WürzburgAm Hubland97074WürzburgGermany
| | - Maik Finze
- Institute for Inorganic ChemistryInstitute for Sustainable Chemistry & Catalysis with BoronJulius-Maximilians-Universität WürzburgAm Hubland97074WürzburgGermany
| | - Lei Ji
- Frontiers Science Center for Flexible Electronics (FSCFE)Shaanxi Institute of Flexible Electronics (SIFE)Northwestern Polytechnical University127 West Youyi Road710072Xi'anP. R. China
| | - Todd B. Marder
- Institute for Inorganic ChemistryInstitute for Sustainable Chemistry & Catalysis with BoronJulius-Maximilians-Universität WürzburgAm Hubland97074WürzburgGermany
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22
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You DK, So H, Ryu CH, Kim M, Lee KM. Strategic molecular design of closo-ortho-carboranyl luminophores to manifest thermally activated delayed fluorescence. Chem Sci 2021; 12:8411-8423. [PMID: 34221322 PMCID: PMC8221186 DOI: 10.1039/d1sc00791b] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2021] [Accepted: 05/11/2021] [Indexed: 11/22/2022] Open
Abstract
In this paper, we propose a strategic molecular design of closo-o-carborane-based donor-acceptor dyad system that exhibits thermally activated delayed fluorescence (TADF) in the solution state at ambient temperature. Planar 9,9-dimethyl-9H-fluorene-based compounds with closo- and nido-o-carborane cages appended at the C2-, C3-, and C4-positions of each fluorene moiety (closo-type: 2FC, 3FC, 4FC, and 4FCH, and nido-type: nido-4FC = [nido-form of 4FC]·[NBu4]) were prepared and characterized. The solid-state molecular structure of 4FC exhibited a significantly distorted fluorene plane, which suggests the existence of severe intramolecular steric hindrance. In photoluminescence measurements, 4FC exhibits a noticeable intramolecular charge transition (ICT)-based emission in all states (solution at 298 K and 77 K, and solid states); however, emissions by other closo-compounds were observed in only the rigid state (solution at 77 K and film). Furthermore, nido-4FC did not exhibit emissive traces in any state. These observations verify that all radiative decay processes correspond to ICT transitions triggered by closo-o-carborane, which acts as an electron acceptor. Relative energy barriers calculated by TD-DFT as dihedral angles around o-carborane cages change in closo-compounds, which indicates that the structural formation of 4FC is nearly fixed around its S0-optimized structure. This differs from that for other closo-compounds, wherein the free rotation of their o-carborane cages occurs easily at ambient temperature. Such rigidity in the structural geometry of 4FC results in ICT-based emission in solution at 298 K and enhancement of quantum efficiency and radiative decay constants compared to those for other closo-compounds. Furthermore, 4FC displays short-lived (∼0.5 ns) and long-lived (∼30 ns) PL decay components in solution at 298 K and in the film state, respectively, which can be attributed to prompt fluorescence and TADF, respectively. The calculated energy difference (ΔE ST) between the first excited singlet and triplet states of the closo-compounds demonstrate that the TADF characteristic of 4FC originates from a significantly small ΔE ST maintained by the rigid structural fixation around its S0-optimized structure. Furthermore, the strategic molecular design of the o-carborane-appended π-conjugated (D-A) system, which forms a rigid geometry due to severe intramolecular steric hindrance, can enhance the radiative efficiency for ICT-based emission and trigger the TADF nature.
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Affiliation(s)
- Dong Kyun You
- Department of Chemistry, Institute for Molecular Science and Fusion Technology, Kangwon National University Chuncheon Gangwon 24341 Republic of Korea
| | - Hyunhee So
- Department of Chemistry, Institute for Molecular Science and Fusion Technology, Kangwon National University Chuncheon Gangwon 24341 Republic of Korea
| | - Chan Hee Ryu
- Department of Chemistry, Institute for Molecular Science and Fusion Technology, Kangwon National University Chuncheon Gangwon 24341 Republic of Korea
| | - Mingi Kim
- Department of Chemistry, Institute for Molecular Science and Fusion Technology, Kangwon National University Chuncheon Gangwon 24341 Republic of Korea
| | - Kang Mun Lee
- Department of Chemistry, Institute for Molecular Science and Fusion Technology, Kangwon National University Chuncheon Gangwon 24341 Republic of Korea
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23
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Lee SH, Mun MS, Lee JH, Im S, Lee W, Hwang H, Lee KM. Impact of the Electronic Environment in Carbazole-Appended o-Carboranyl Compounds on the Intramolecular-Charge-Transfer-Based Radiative Decay Efficiency. Organometallics 2021. [DOI: 10.1021/acs.organomet.1c00060] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Affiliation(s)
- Seok Ho Lee
- Department of Chemistry and Institute for Molecular Science and Fusion Technology, Kangwon National University, Chuncheon, Gangwon 24341, Republic of Korea
| | - Min Sik Mun
- Department of Chemistry and Institute for Molecular Science and Fusion Technology, Kangwon National University, Chuncheon, Gangwon 24341, Republic of Korea
| | - Ji Hye Lee
- Department of Chemistry and Institute for Molecular Science and Fusion Technology, Kangwon National University, Chuncheon, Gangwon 24341, Republic of Korea
| | - Sehee Im
- Department of Chemistry and Institute for Molecular Science and Fusion Technology, Kangwon National University, Chuncheon, Gangwon 24341, Republic of Korea
| | - Wonchul Lee
- Department of Chemistry and Institute for Molecular Science and Fusion Technology, Kangwon National University, Chuncheon, Gangwon 24341, Republic of Korea
| | - Hyonseok Hwang
- Department of Chemistry and Institute for Molecular Science and Fusion Technology, Kangwon National University, Chuncheon, Gangwon 24341, Republic of Korea
| | - Kang Mun Lee
- Department of Chemistry and Institute for Molecular Science and Fusion Technology, Kangwon National University, Chuncheon, Gangwon 24341, Republic of Korea
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24
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Lee SH, Lee JH, Mun MS, Yi S, Yoo E, Hwang H, Lee KM. Influence of Electronic Environment on the Radiative Efficiency of 9-Phenyl-9 H-carbazole-Based ortho-Carboranyl Luminophores. Molecules 2021; 26:molecules26061763. [PMID: 33801078 PMCID: PMC8003977 DOI: 10.3390/molecules26061763] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2021] [Revised: 03/19/2021] [Accepted: 03/19/2021] [Indexed: 11/16/2022] Open
Abstract
The photophysical properties of closo-ortho-carboranyl-based donor–acceptor dyads are known to be affected by the electronic environment of the carborane cage but the influence of the electronic environment of the donor moiety remains unclear. Herein, four 9-phenyl-9H-carbazole-based closo-ortho-carboranyl compounds (1F, 2P, 3M, and 4T), in which an o-carborane cage was appended at the C3-position of a 9-phenyl-9H-carbazole moiety bearing various functional groups, were synthesized and fully characterized using multinuclear nuclear magnetic resonance spectroscopy and elemental analysis. Furthermore, the solid-state molecular structures of 1F and 4T were determined by X-ray diffraction crystallography. For all the compounds, the lowest-energy absorption band exhibited a tail extending to 350 nm, attributable to the spin-allowed π–π* transition of the 9-phenyl-9H-carbazole moiety and weak intramolecular charge transfer (ICT) between the o-carborane and the carbazole group. These compounds showed intense yellowish emission (λem = ~540 nm) in rigid states (in tetrahydrofuran (THF) at 77 K and in films), whereas considerably weak emission was observed in THF at 298 K. Theoretical calculations on the first excited states (S1) of the compounds suggested that the strong emission bands can be assigned to the ICT transition involving the o-carborane. Furthermore, photoluminescence experiments in THF‒water mixtures demonstrated that aggregation-induced emission was responsible for the emission in rigid states. Intriguingly, the quantum yields and radiative decay constants in the film state were gradually enhanced with the increasing electron-donating ability of the substituent on the 9-phenyl group (‒F for 1F < ‒H for 2P < ‒CH3 for 3M < ‒C(CH3)3 for 4T). These features indicate that the ICT-based radiative decay process in rigid states is affected by the electronic environment of the 9-phenyl-9H-carbazole group. Consequently, the efficient ICT-based radiative decay of o-carboranyl compounds can be achieved by appending the o-carborane cage with electron-rich aromatic systems.
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25
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Kim M, Im S, Ryu CH, Lee SH, Hong JH, Lee KM. Impact of deboronation on the electronic characteristics of closo-o-carborane: intriguing photophysical changes in triazole-appended carboranyl luminophores. Dalton Trans 2021; 50:3207-3215. [PMID: 33576753 DOI: 10.1039/d0dt04038j] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
5-Phenyl-1,2,4-triazole-appended closo- (CB1 and CB2) and nido-o-carboranyl (nido-CB1 and nido-CB2) compounds were prepared and fully characterized using multinuclear NMR spectroscopy and elemental analysis. The solid-state molecular structures of both closo-compounds were analyzed by X-ray crystallography. Although the closo-compounds exhibited dual emissive patterns in the rigid state (in THF at 77 K), which were assignable to a π-π* local excitation (LE)-based emission (λem = ca. 380 nm) on the triazole moieties and to an intramolecular charge transfer (ICT)-based emission (ca. 460 nm) in which the o-carborane units acted as the acceptor (A), at 298 K in THF, the LE-based emission dominated. In contrast, the nido-compounds exhibited an intensive emission originating from ICT transitions in which the o-carborane units reversibly acted as the donor (D). In particular, the positive solvatochromic effects of both nido-compounds and the results of theoretical calculations for the o-carboranyl compounds supported the electronic role of the o-carboranyl unit in each compound. Investigation of the radiative decay mechanism of the closo- and nido-compounds using their quantum efficiency (Φem) and decay lifetime (τobs) suggested that the ICT-based radiative decay of nido-compounds occurred more efficiently than the LE-based decay of closo-compounds. These results implied that emission from the closo-compounds was drastically enhanced by the deboronation reaction upon exposure to an increasing concentration of fluoride anions, and finally became similar to the emission color (sky-blue) of the nido-compounds.
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Affiliation(s)
- Mingi Kim
- Department of Chemistry, Institute for Molecular Science and Fusion Technology, Kangwon National University, Chuncheon, Gangwon 24341, Republic of Korea.
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26
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Tuning the Liquid Crystallinity of Cholesteryl-o-Carborane Dyads: Synthesis, Structure, Photoluminescence, and Mesomorphic Properties. CRYSTALS 2021. [DOI: 10.3390/cryst11020133] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
A set of mesomorphic materials in which the o-carborane cluster is covalently bonded to a cholesteryl benzoate moiety (mesogen group) through a suitably designed linker is described. The olefin cross-metathesis between appropriately functionalized styrenyl-o-carborane derivatives and a terminal alkenyl cholesteryl benzoate mesogen (all type I terminal olefins) leads to the desired trans-regioisomer, which is the best-suited configuration to obtain mesomorphic properties in the final materials. The introduction of different substituents (R = H (M2), Me (M3), or Ph (M4)) to one of the carbon atoms of the o-carborane cluster (Ccluster) enables the tailoring of liquid crystalline properties. Compounds M2 and M3 show the chiral nematic (N*) phase, whereas M4 do not show liquid crystal behavior. Weaker intermolecular interactions in the solid M3 with respect to those in M2 may allow the liquid crystallinity in M3 to be expressed as enantiotropic behavior, whereas breaking the stronger intermolecular interaction in the solid state of M2 leads directly to the isotropic state, resulting in monotropic behavior. Remarkably, M3 also displays the blue phase, which was observed neither in the chiral nematic precursor nor in the styrenyl-cholesterol model (M5) without an o-carborane cluster, which suggests that the presence of the cluster plays a role in stabilizing this highly twisted chiral phase. In the carborane-containing mesogens (M2 and M3), the o-carborane cluster can be incorporated without destroying the helical organization of the mesophase.
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27
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Marsh AV, Little M, Cheetham NJ, Dyson MJ, Bidwell M, White AJP, Warriner CN, Swain AC, McCulloch I, Stavrinou PN, Heeney M. Highly Deformed o-Carborane Functionalised Non-linear Polycyclic Aromatics with Exceptionally Long C-C Bonds. Chemistry 2021; 27:1970-1975. [PMID: 33044792 PMCID: PMC7898797 DOI: 10.1002/chem.202004517] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Indexed: 11/16/2022]
Abstract
The effect of substituting o-carborane into the most sterically hindered positions of phenanthrene and benzo(k)tetraphene is reported. Synthesised via a Bull-Hutchings-Quayle benzannulation, the crystal structures of these non-linear acenes exhibited the highest aromatic deformation parameters observed for any reported carborane compound to date, and among the largest carboranyl C-C bond length of all organo-substituted o-carboranes. Photoluminescence studies of these compounds demonstrated efficient intramolecular charge-transfer, leading to aggregation induced emission properties. Additionally, an unusual low-energy excimer was observed for the phenanthryl compound. These are two new members of the family of carborane-functionalised non-linear acenes, notable for their peculiar structures and multi-luminescent properties.
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Affiliation(s)
- Adam V. Marsh
- Department of Chemistry and Centre for Processable ElectronicsImperial College LondonLondonSW7 2AZUK
| | - Mark Little
- Department of Chemistry and Centre for Processable ElectronicsImperial College LondonLondonSW7 2AZUK
| | - Nathan J. Cheetham
- Department of Physics and Centre for Processable ElectronicsImperial College LondonLondonSW7 2AZUK
| | - Matthew J. Dyson
- Molecular Materials and Nanosystems and Institute for Complex Molecular SystemsEindhoven University of Technology5600 MBEindhovenNetherlands
| | - Matthew Bidwell
- Department of Chemistry and Centre for Processable ElectronicsImperial College LondonLondonSW7 2AZUK
| | - Andrew J. P. White
- Department of Chemistry and Centre for Processable ElectronicsImperial College LondonLondonSW7 2AZUK
| | | | | | - Iain McCulloch
- Department of ChemistryChemistry Research LaboratoryUniversity of OxfordOxfordOX1 3TAUK
| | - Paul N. Stavrinou
- Department of Engineering ScienceUniversity of OxfordOxfordOX1 3PJUK
| | - Martin Heeney
- Department of Chemistry and Centre for Processable ElectronicsImperial College LondonLondonSW7 2AZUK
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28
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Parejo L, Chaari M, Santiago S, Guirado G, Teixidor F, Núñez R, Hernando J. Reversibly Switchable Fluorescent Molecular Systems Based on Metallacarborane-Perylenediimide Conjugates. Chemistry 2021; 27:270-280. [PMID: 32648595 DOI: 10.1002/chem.202002419] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2020] [Indexed: 12/31/2022]
Abstract
Icosahedral metallacarboranes are θ-shaped anionic molecules in which two icosahedra share one vertex that is a metal center. The most remarkable of these compounds is the anionic cobalt-based metallacarborane [Co(C2 B9 H11 )2 ]- , whose oxidation-reduction processes occur via an outer sphere electron process. This, along with its low density negative charge, makes [Co(C2 B9 H11 )2 ]- very appealing to participate in electron-transfer processes. In this work, [Co(C2 B9 H11 )2 ]- is tethered to a perylenediimide dye to produce the first examples of switchable luminescent molecules and materials based on metallacarboranes. In particular, the electronic communication of [Co(C2 B9 H11 )2 ]- with the appended chromophore unit in these compounds can be regulated upon application of redox stimuli, which allows the reversible modulation of the emitted fluorescence. As such, they behave as electrochemically-controlled fluorescent molecular switches in solution, which surpass the performance of previous systems based on conjugates of perylendiimides with ferrocene. Remarkably, they can form gels by treatment with appropriate mixtures of organic solvents, which result from the self-assembly of the cobaltabisdicarbollide-perylendiimide conjugates into 1D nanostructures. The interplay between dye π-stacking and metallacarborane electronic and steric interactions ultimately governs the supramolecular arrangement in these materials, which for one of the compounds prepared allows preserving the luminescent behavior in the gel state.
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Affiliation(s)
- Laura Parejo
- Departament de Química, Universitat Autònoma de Barcelona, 08193, Barcelona, Spain
| | - Mahdi Chaari
- Institut de Ciencia de Materials de Barcelona (ICMAB-CSIC), Campus de la UAB, 08193, Barcelona, Spain
| | - Sara Santiago
- Departament de Química, Universitat Autònoma de Barcelona, 08193, Barcelona, Spain
| | - Gonzalo Guirado
- Departament de Química, Universitat Autònoma de Barcelona, 08193, Barcelona, Spain
| | - Francesc Teixidor
- Institut de Ciencia de Materials de Barcelona (ICMAB-CSIC), Campus de la UAB, 08193, Barcelona, Spain
| | - Rosario Núñez
- Institut de Ciencia de Materials de Barcelona (ICMAB-CSIC), Campus de la UAB, 08193, Barcelona, Spain
| | - Jordi Hernando
- Departament de Química, Universitat Autònoma de Barcelona, 08193, Barcelona, Spain
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29
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Li J, Xu J, Yan L, Lu C, Yan H. A "flexible" carborane-cored luminogen: variable emission behaviours in aggregates. Dalton Trans 2021; 50:8029-8035. [PMID: 34009227 DOI: 10.1039/d1dt00233c] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The performance of tunable emissions in aggregates is highly desirable but challenging owing to the restricted molecular conformations of luminogens. Herein, we designed and synthesized a new "flexible" luminogen, a carborane-cored compound NAPH, which exhibits variable photophysical behaviours in aggregates, such as aggregation-induced emission, crystallization-induced emission, polymorph-dependent emission, and mechanochromic luminescence. Moreover, the two polymorphs with different emission colors show opposite mechano-responsive luminescence, which is rarely observed for single-component luminescent materials. Both theoretical calculations and photophysical experiments reveal that the carborane-cored luminogen could afford variable conformations. This endows the whole molecule with multiple conformations in aggregates, thus leading to variable emission behaviours. Therefore, the present work provides new access to the construction of multifunctional single-component solid-state luminescent materials.
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Affiliation(s)
- Jiaxin Li
- State Key Laboratory of Coordination Chemistry, Jiangsu Key Laboratory of Advanced Organic Materials, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, P. R. China.
| | - Jinkai Xu
- State Key Laboratory of Coordination Chemistry, Jiangsu Key Laboratory of Advanced Organic Materials, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, P. R. China.
| | - Linbo Yan
- Sports Biochemistry Lab, College of Physical Education and Health, Guangxi Normal University, Guilin 541006, China
| | - Changsheng Lu
- State Key Laboratory of Coordination Chemistry, Jiangsu Key Laboratory of Advanced Organic Materials, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, P. R. China.
| | - Hong Yan
- State Key Laboratory of Coordination Chemistry, Jiangsu Key Laboratory of Advanced Organic Materials, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, P. R. China.
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30
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Ochi J, Tanaka K, Chujo Y. Experimental proof for emission annihilation through bond elongation at the carbon-carbon bond in o-carborane with fused biphenyl-substituted compounds. Dalton Trans 2020; 50:1025-1033. [PMID: 33367426 DOI: 10.1039/d0dt03618h] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Because of their unique luminescence properties, such as aggregation-induced emission (AIE), intense solid-state luminescence and stimuli-responsive luminochromism, aryl-substituted o-carboranes have attracted attention as a platform for developing functional optoelectronic materials. However, there still remains one fundamental issue with the detailed mechanism of solution quenching in AIE behaviors. Aryl-modified o-carboranes with AIE properties exhibit intense emission not in solution but in the solid state. According to quantum calculations and many experimental results, the elongation at the carbon-carbon bond in o-carborane in the excited state, followed by nonradiative decay, has been proposed as a main path for emission annihilation in solution. However, intramolecular rotation would simultaneously occur, and there is a possibility that emission annihilation could be induced by the combination of both bond elongation and rotation. In this study, we designed two types of biphenyl-substituted o-carboranes having fused structures at the neighbor carbon and boron atoms for fixing molecular conformation. In these molecules, bond elongation is allowed, while rotation would be prohibited. From the series of optical measurements and theoretical investigations, we proved that emission annihilation can occur through bond elongation in the absence of rotation. Moreover, we show that bond elongation could be suppressed by introducing a bulky substituent at the adjacent carbon, and emission color tuning was achieved. This is the first example, to the best of our knowledge, to prove that excitation decay can proceed only through bond elongation without electronic perturbation caused by rotation.
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Affiliation(s)
- Junki Ochi
- Department of Polymer Chemistry, Graduate School of Engineering, Kyoto University Katsura, Nishikyo-ku, Kyoto 615-8510, Japan.
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31
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Sujith S, Lee MH. Synthesis and Delayed Fluorescent Properties of
p‐Nido
‐Carborane‐Triarylborane
Conjugates with a
Methyl‐Substituted
Phenylene Linker. B KOREAN CHEM SOC 2020. [DOI: 10.1002/bkcs.12149] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Surendran Sujith
- Department of Chemistry University of Ulsan Ulsan 44610 Republic of Korea
| | - Min Hyung Lee
- Department of Chemistry University of Ulsan Ulsan 44610 Republic of Korea
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32
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Smyshliaeva LA, Varaksin MV, Fomina EI, Joy MN, Bakulev VA, Charushin VN, Chupakhin ON. Cu(I)-Catalyzed Cycloaddition of Vinylacetylene ortho-Carborane and Arylazides in the Design of 1,2,3-Triazolyl-Modified Vinylcarborane Fluorophores. Organometallics 2020. [DOI: 10.1021/acs.organomet.0c00478] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Lidia A. Smyshliaeva
- Ural Federal University, 19 Mira Str., 620002 Ekaterinburg, Russia
- Institute of Organic Synthesis, Ural Branch of the Russian Academy of Sciences, 22 S. Kovalevskaya Street, 620990 Ekaterinburg, Russia
| | - Mikhail V. Varaksin
- Ural Federal University, 19 Mira Str., 620002 Ekaterinburg, Russia
- Institute of Organic Synthesis, Ural Branch of the Russian Academy of Sciences, 22 S. Kovalevskaya Street, 620990 Ekaterinburg, Russia
| | | | | | - Vasiliy A. Bakulev
- Ural Federal University, 19 Mira Str., 620002 Ekaterinburg, Russia
- Institute of Organic Synthesis, Ural Branch of the Russian Academy of Sciences, 22 S. Kovalevskaya Street, 620990 Ekaterinburg, Russia
| | - Valery N. Charushin
- Ural Federal University, 19 Mira Str., 620002 Ekaterinburg, Russia
- Institute of Organic Synthesis, Ural Branch of the Russian Academy of Sciences, 22 S. Kovalevskaya Street, 620990 Ekaterinburg, Russia
| | - Oleg N. Chupakhin
- Ural Federal University, 19 Mira Str., 620002 Ekaterinburg, Russia
- Institute of Organic Synthesis, Ural Branch of the Russian Academy of Sciences, 22 S. Kovalevskaya Street, 620990 Ekaterinburg, Russia
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33
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Deboronation-Induced Ratiometric Emission Variations of Terphenyl-Based Closo- o-Carboranyl Compounds: Applications to Fluoride-Sensing. Molecules 2020; 25:molecules25102413. [PMID: 32455846 PMCID: PMC7287808 DOI: 10.3390/molecules25102413] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2020] [Revised: 05/20/2020] [Accepted: 05/21/2020] [Indexed: 01/02/2023] Open
Abstract
Closo-o-carboranyl compounds bearing the ortho-type perfectly distorted or planar terphenyl rings (closo-DT and closo-PT, respectively) and their nido-derivatives (nido-DT and nido-PT, respectively) were synthesized and fully characterized using multinuclear NMR spectroscopy and elemental analysis. Although the emission spectra of both closo-compounds exhibited intriguing emission patterns in solution at 298 and 77 K, in the film state, closo-DT mainly exhibited a π-π* local excitation (LE)-based emission in the high-energy region, whereas closo-PT produced an intense emission in the low-energy region corresponding to an intramolecular charge transfer (ICT) transition. In particular, the positive solvatochromic effect of closo-PT and theoretical calculation results at the first excited (S1) optimized structure of both closo-compounds strongly suggest that these dual-emissive bands at the high- and low-energy can be assigned to each π-π* LE and ICT transition. Interestingly, both the nido-compounds, nido-DT and nido-PT, exhibited the only LE-based emission in solution at 298 K due to the anionic character of the nido-o-carborane cages, which cannot cause the ICT transitions. The specific emissive features of nido-compounds indicate that the emissive color of closo-PT in solution at 298 K is completely different from that of nido-PT. As a result, the deboronation of closo-PT upon exposure to increasing concentrations of fluoride anion exhibits a dramatic ratiometric color change from orange to deep blue via turn-off of the ICT-based emission. Consequently, the color change response of the luminescence by the alternation of the intrinsic electronic transitions via deboronation as well as the structural feature of terphenyl rings indicates the potential of the developed closo-o-carboranyl compounds that exhibit the intense ICT-based emission, as naked-eye-detectable chemodosimeters for fluoride ion sensing.
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34
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35
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Lee S, Shin J, Ko DH, Han WS. A new type of carborane-based electron-accepting material. Chem Commun (Camb) 2020; 56:12741-12744. [DOI: 10.1039/d0cc04684a] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Direct attachment of the ethynyl group significantly affects the electrochemical properties of o-Cb systems.
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Affiliation(s)
- Sunhee Lee
- Department of Chemistry
- Seoul Women's University
- Seoul 01797
- Republic of Korea
| | - Jisu Shin
- Department of Applied Chemistry
- Kyung Hee University
- Yongin
- Republic of Korea
| | - Doo-Hyun Ko
- Department of Applied Chemistry
- Kyung Hee University
- Yongin
- Republic of Korea
| | - Won-Sik Han
- Department of Chemistry
- Seoul Women's University
- Seoul 01797
- Republic of Korea
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36
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Kim M, Ryu CH, Hong JH, Lee JH, Hwang H, Lee KM. Planarity of N-aryl in appended 1,2,4-triazole-based o-carboranyl luminophores: a key factor to control intramolecular charge transfer. Inorg Chem Front 2020. [DOI: 10.1039/d0qi00915f] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
The distinct difference in the photophysical characteristics between two triazole-based o-carboranes revealed that the planarity of aryl groups strongly influences intramolecular-charge-transfer-based emission.
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Affiliation(s)
- Mingi Kim
- Department of Chemistry
- Institute for Molecular Science and Fusion Technology
- Kangwon National University
- Chuncheon
- Republic of Korea
| | - Chan Hee Ryu
- Department of Chemistry
- Institute for Molecular Science and Fusion Technology
- Kangwon National University
- Chuncheon
- Republic of Korea
| | - Ju Hyun Hong
- Department of Chemistry
- Institute for Molecular Science and Fusion Technology
- Kangwon National University
- Chuncheon
- Republic of Korea
| | - Ji Hye Lee
- Department of Chemistry
- Institute for Molecular Science and Fusion Technology
- Kangwon National University
- Chuncheon
- Republic of Korea
| | - Hyonseok Hwang
- Department of Chemistry
- Institute for Molecular Science and Fusion Technology
- Kangwon National University
- Chuncheon
- Republic of Korea
| | - Kang Mun Lee
- Department of Chemistry
- Institute for Molecular Science and Fusion Technology
- Kangwon National University
- Chuncheon
- Republic of Korea
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37
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Kim S, Lee JH, So H, Kim M, Mun MS, Hwang H, Park MH, Lee KM. Insights into the effects of substitution position on the photophysics of mono-o-carborane-substituted pyrenes. Inorg Chem Front 2020. [DOI: 10.1039/d0qi00563k] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Mono-o-carborane-substituted pyrenes were prepared and apparently showed the effects of substitution position on their photophysical property.
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Affiliation(s)
- Seonah Kim
- Department of Chemistry
- Institute for Molecular Science and Fusion Technology
- Kangwon National University
- Chuncheon
- Republic of Korea
| | - Ji Hye Lee
- Department of Chemistry
- Institute for Molecular Science and Fusion Technology
- Kangwon National University
- Chuncheon
- Republic of Korea
| | - Hyunhee So
- Department of Chemistry
- Institute for Molecular Science and Fusion Technology
- Kangwon National University
- Chuncheon
- Republic of Korea
| | - Mingi Kim
- Department of Chemistry
- Institute for Molecular Science and Fusion Technology
- Kangwon National University
- Chuncheon
- Republic of Korea
| | - Min Sik Mun
- Department of Chemistry
- Institute for Molecular Science and Fusion Technology
- Kangwon National University
- Chuncheon
- Republic of Korea
| | - Hyonseok Hwang
- Department of Chemistry
- Institute for Molecular Science and Fusion Technology
- Kangwon National University
- Chuncheon
- Republic of Korea
| | - Myung Hwan Park
- Department of Chemistry Education
- Chungbuk National University
- Cheongju
- Republic of Korea
| | - Kang Mun Lee
- Department of Chemistry
- Institute for Molecular Science and Fusion Technology
- Kangwon National University
- Chuncheon
- Republic of Korea
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38
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Sujith S, Nam EB, Lee J, Lee SU, Lee MH. Enhancing the thermally activated delayed fluorescence of nido-carborane-appended triarylboranes by steric modification of the phenylene linker. Inorg Chem Front 2020. [DOI: 10.1039/d0qi00535e] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The introduction of a methyl group into the 4-position of the phenylene linker of nido-carborane–triarylborane D–A dyads, i.e., at the ortho position to the nido-carborane cage, largely enhances their thermally activated delayed fluorescence.
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Affiliation(s)
- Surendran Sujith
- Department of Chemistry
- University of Ulsan
- Ulsan 44610
- Republic of Korea
| | - Eun Bi Nam
- Department of Bionano Technology and Department of Applied Chemistry
- Hanyang University
- Ansan 15588
- Republic of Korea
| | - Junseong Lee
- Department of Chemistry
- Chonnam National University
- Gwangju 61186
- Republic of Korea
| | - Sang Uck Lee
- Department of Bionano Technology and Department of Applied Chemistry
- Hanyang University
- Ansan 15588
- Republic of Korea
| | - Min Hyung Lee
- Department of Chemistry
- University of Ulsan
- Ulsan 44610
- Republic of Korea
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39
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Kim S, Lee JH, So H, Ryu J, Lee J, Hwang H, Kim Y, Park MH, Lee KM. Spirobifluorene-Based o-Carboranyl Compounds: Insights into the Rotational Effect of Carborane Cages on Photoluminescence. Chemistry 2019; 26:548-557. [PMID: 31657858 DOI: 10.1002/chem.201904491] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2019] [Revised: 10/25/2019] [Indexed: 12/13/2022]
Abstract
9,9'-Spirobifluorene-based closo-o-carboranyl (SFC1 and SFC2) compounds and their nido-derivatives (nido-SFC1 and nido-SFC2) were prepared and characterized. The two closo-compounds displayed major absorption bands assignable to π-π* transitions involving the spirobifluorene group, as well as weak intramolecular charge-transfer (ICT) transitions between the o-carboranes and their spirobifluorene moieties. The nido-compounds exhibited slightly blueshifted absorption bands resulting from the absence of the ICT transitions corresponding to the o-carborane moieties due to the anionic character of the nido-o-carboranes. While SFC1 exhibited only high-energy emissions in THF at 298 K (only from locally excited (LE) states assignable to π-π* transitions on the spirobifluorene group), remarkable emissions in the low-energy region were observed in the rigid state such as in THF at 77 K and in the film state. SFC2 displayed intense emissions in the low-energy region in all states. The fact that neither of the nido-derivatives of SFC1 and SFC2 exhibited low-energy emissions and the TD-DFT calculation results of each closo-compound clearly verified that the low-energy emission was based on ICT-based radiative decay. The conformational barriers from each relative energy calculation upon changing the dihedral angles around the o-carborane cages for both compounds confirmed that the rotation of the o-carborane cages and terminal phenyl rings for SFC1 is freer than that for SFC2.
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Affiliation(s)
- Seonah Kim
- Department of Chemistry, Institute for Molecular Science and Fusion Technology, Kangwon National University, Chuncheon, Gangwon, 24341, Republic of Korea
| | - Ji Hye Lee
- Department of Chemistry, Institute for Molecular Science and Fusion Technology, Kangwon National University, Chuncheon, Gangwon, 24341, Republic of Korea
| | - Hyunhee So
- Department of Chemistry, Institute for Molecular Science and Fusion Technology, Kangwon National University, Chuncheon, Gangwon, 24341, Republic of Korea
| | - Jiyeon Ryu
- Department of Chemistry, Chonnam National University, Gwangju, 61186, Republic of Korea
| | - Junseong Lee
- Department of Chemistry, Chonnam National University, Gwangju, 61186, Republic of Korea
| | - Hyonseok Hwang
- Department of Chemistry, Institute for Molecular Science and Fusion Technology, Kangwon National University, Chuncheon, Gangwon, 24341, Republic of Korea
| | - Youngjo Kim
- Department of Chemistry, Chungbuk National University, Cheongju, Chungbuk, 28644, Republic of Korea
| | - Myung Hwan Park
- Department of Chemistry Education, Chungbuk National University, Cheongju, Chungbuk, 28644, Republic of Korea
| | - Kang Mun Lee
- Department of Chemistry, Institute for Molecular Science and Fusion Technology, Kangwon National University, Chuncheon, Gangwon, 24341, Republic of Korea
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40
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So H, Kim JH, Lee JH, Hwang H, An DK, Lee KM. Planarity of terphenyl rings possessing o-carborane cages: turning on intramolecular-charge-transfer-based emission. Chem Commun (Camb) 2019; 55:14518-14521. [PMID: 31737876 DOI: 10.1039/c9cc07729d] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
To clarify the relationship between planarity and intramolecular charge transfer (ICT), two o-carboranyl compounds (TCB and FCB) containing different ortho-type terphenyl rings, namely, perfectly distorted or planar phenyl rings, were synthesised and fully characterised. Although the emission spectra of both compounds presented intriguing dual-emission patterns in solution at 298 or 77 K and in the film state, distorted TCB mostly showed locally excited emission, whereas planar FCB demonstrated intense emission corresponding to an ICT transition. Interestingly, the emission efficiencies and radiative decay constants of terphenyl-based o-carboranyl compounds were gradually enhanced by increasing the planarity of the terphenyl groups. These results verify the existence of a strong relationship between the planarity of appended aryl groups and ICT-based radiative decay in o-carborane-substituted compounds.
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Affiliation(s)
- Hyunhee So
- Department of Chemistry, Institute for Molecular Science and Fusion Technology, Kangwon National University, Chuncheon, Gangwon 24341, Republic of Korea.
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41
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Photophysical Properties of Spirobifluorene-Based o-Carboranyl Compounds Altered by Structurally Rotating the Carborane Cages. Molecules 2019; 24:molecules24224135. [PMID: 31731632 PMCID: PMC6891568 DOI: 10.3390/molecules24224135] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2019] [Revised: 11/11/2019] [Accepted: 11/13/2019] [Indexed: 11/25/2022] Open
Abstract
9,9′-Spirobifluorene-based o-carboranyl compounds C1 and C2 were prepared and fully characterized by multinuclear nuclear magnetic resonance (NMR) spectroscopy and elemental analysis. The solid-state structure of C1 was also determined by single-crystal X-ray diffractometry. The two carboranyl compounds display major absorption bands that are assigned to π−π* transitions involving their spirobifluorene groups, as well as weak intramolecular charge-transfer (ICT) transitions between the o-carboranes and their spirobifluorene groups. While C1 only exhibited high-energy emissions (λem = ca. 350 nm) in THF at 298 K due to locally excited (LE) states assignable to π−π* transitions involving the spirobifluorene group alone, a remarkable emission in the low-energy region was observed in the rigid state, such as in THF at 77 K or the film state. Furthermore, C2 displays intense dual emissive patterns in both high- and low-energy regions in all states. Electronic transitions that were calculated by time-dependent-DFT (TD-DFT) for each compound based on ground (S0) and first-excited (S1) state optimized structures clearly verify that the low-energy emissions are due to ICT-based radiative decays. Calculated energy barriers that are based on the relative energies associated with changes in the dihedral angle around the o-carborane cages in C1 and C2 clearly reveal that the o-carborane cage in C1 rotates more freely than that in C2. All of the molecular features indicate that ICT-based radiative decay is only available to the rigid state in the absence of structural fluctuations, in particular the free-rotation of the o-carborane cage.
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42
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Martin KL, Smith JN, Young ER, Carter KR. Synthetic Emission Tuning of Carborane-Containing Poly(dihexylfluorene)s. Macromolecules 2019. [DOI: 10.1021/acs.macromol.9b01325] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Affiliation(s)
- Kara L. Martin
- Department of Polymer Science and Engineering, University of Massachusetts—Amherst, 120 Governors Drive, Amherst, Massachusetts 01003, United States
| | - Jessica N. Smith
- Department of Polymer Science and Engineering, University of Massachusetts—Amherst, 120 Governors Drive, Amherst, Massachusetts 01003, United States
| | - Elizabeth R. Young
- Department of Chemistry, Lehigh University, 6 East Packer Avenue, Bethlehem, Pennsylvania 18015, United States
| | - Kenneth R. Carter
- Department of Polymer Science and Engineering, University of Massachusetts—Amherst, 120 Governors Drive, Amherst, Massachusetts 01003, United States
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43
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Yang X, Zhang B, Zhang S, Li G, Xu L, Wang Z, Li P, Zhang Y, Liu Z, He G. The Marriage of Carborane with Chalcogen Atoms: Nonconjugation, σ−π Conjugation, and Intramolecular Charge Transfer. Org Lett 2019; 21:8285-8289. [DOI: 10.1021/acs.orglett.9b03047] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Xiaodong Yang
- Frontier Institute of Science and Technology, State Key Laboratory for Strength and Vibration of Mechanical Structures, Xi’an Key Laboratory of Sustainable Energy Materials Chemistry, Xi’an Jiaotong University, Xi’an, Shaanxi Province 710054, China
| | - Bingjie Zhang
- Frontier Institute of Science and Technology, State Key Laboratory for Strength and Vibration of Mechanical Structures, Xi’an Key Laboratory of Sustainable Energy Materials Chemistry, Xi’an Jiaotong University, Xi’an, Shaanxi Province 710054, China
| | - Sikun Zhang
- Frontier Institute of Science and Technology, State Key Laboratory for Strength and Vibration of Mechanical Structures, Xi’an Key Laboratory of Sustainable Energy Materials Chemistry, Xi’an Jiaotong University, Xi’an, Shaanxi Province 710054, China
| | - Guoping Li
- Frontier Institute of Science and Technology, State Key Laboratory for Strength and Vibration of Mechanical Structures, Xi’an Key Laboratory of Sustainable Energy Materials Chemistry, Xi’an Jiaotong University, Xi’an, Shaanxi Province 710054, China
| | - Letian Xu
- Frontier Institute of Science and Technology, State Key Laboratory for Strength and Vibration of Mechanical Structures, Xi’an Key Laboratory of Sustainable Energy Materials Chemistry, Xi’an Jiaotong University, Xi’an, Shaanxi Province 710054, China
| | - Zhijun Wang
- Frontier Institute of Science and Technology, State Key Laboratory for Strength and Vibration of Mechanical Structures, Xi’an Key Laboratory of Sustainable Energy Materials Chemistry, Xi’an Jiaotong University, Xi’an, Shaanxi Province 710054, China
| | - Pengfei Li
- Frontier Institute of Science and Technology, State Key Laboratory for Strength and Vibration of Mechanical Structures, Xi’an Key Laboratory of Sustainable Energy Materials Chemistry, Xi’an Jiaotong University, Xi’an, Shaanxi Province 710054, China
| | - Yanfeng Zhang
- Department of Applied Chemistry, School of Science, Xi’an Jiaotong University, Xi’an, Shaanxi Province 710054, China
| | - Zishun Liu
- International Center for Applied Mechanics, State Key Laboratory for Strength and Vibration of Mechanical Structures, School of Aerospace, Xi’an Jiaotong University, Xi’an 710049, China
| | - Gang He
- Frontier Institute of Science and Technology, State Key Laboratory for Strength and Vibration of Mechanical Structures, Xi’an Key Laboratory of Sustainable Energy Materials Chemistry, Xi’an Jiaotong University, Xi’an, Shaanxi Province 710054, China
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44
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Jiang P, Wang Z, Moxey GJ, Morshedi M, Barlow A, Wang G, Quintana C, Zhang C, Cifuentes MP, Humphrey MG. Syntheses and quadratic nonlinear optical properties of 2,7-fluorenylene- and 1,4-phenylene-functionalized o-carboranes. Dalton Trans 2019; 48:12549-12559. [PMID: 31367717 DOI: 10.1039/c9dt02645b] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
o-Carboranes C-functionalized by (4-substituted-phen-1-yl)ethynyl-1,4-phenyl groups or (2-substituted-fluoren-7-yl)ethynyl-2,7-fluorenyl groups, in which the pendant functionalization is electron-withdrawing nitro or electron-donating diphenylamino groups, have been synthesized and in many cases structurally characterized. Diphenylamino-containing examples coupled via the two π-delocalizable bridges to the electron-accepting o-carborane unit exhibit the greater quadratic optical nonlinearities at 1064 nm (hyper-Rayleigh scattering, ns pulses), the nonlinearities also increasing on proceeding from 1,4-phenylene- to 2,7-fluorenylene-containing bridge. The most NLO-efficient example 2-(n-butyl)-1-(2-((9,9-di(n-butyl)-2-(N,N-diphenylamino)-9H-fluoren-7-yl)ethynyl)-9,9-di(n-butyl)-9H-fluoren-7-yl)-1,2-ortho-carborane, consisting of diphenylamino donor, fluorenyl-containing bridge, o-carborane acceptor, and solubilizing n-butyl units, exhibits large 〈β〉HRS (230 × 10-30 esu) and frequency-independent (two-level model) 〈β0〉 (96 × 10-30 esu) values. Coupling two (2-((9,9-di(n-butyl)-2-(N,N-diphenylamino)-9H-fluoren-7-yl)ethynyl)-9,9-di(n-butyl)-9H-fluoren-7-yl) units to the 1,2-ortho-carborane core affords a di-C-functionalized compound with enhanced nonlinearities (309 × 10-30 esu and 129 × 10-30 esu, respectively).
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Affiliation(s)
- Peng Jiang
- School of Chemical and Material Engineering, Jiangnan University, Wuxi 214122, Jiangsu Province, China.
| | - Zhaojin Wang
- School of Chemical and Material Engineering, Jiangnan University, Wuxi 214122, Jiangsu Province, China.
| | - Graeme J Moxey
- Research School of Chemistry, Australian National University, Canberra, ACT 2601, Australia
| | - Mahbod Morshedi
- Research School of Chemistry, Australian National University, Canberra, ACT 2601, Australia
| | - Adam Barlow
- Research School of Chemistry, Australian National University, Canberra, ACT 2601, Australia
| | - Genmiao Wang
- Research School of Chemistry, Australian National University, Canberra, ACT 2601, Australia
| | - Cristóbal Quintana
- Research School of Chemistry, Australian National University, Canberra, ACT 2601, Australia
| | - Chi Zhang
- School of Chemical and Material Engineering, Jiangnan University, Wuxi 214122, Jiangsu Province, China.
| | - Marie P Cifuentes
- School of Chemical and Material Engineering, Jiangnan University, Wuxi 214122, Jiangsu Province, China. and Research School of Chemistry, Australian National University, Canberra, ACT 2601, Australia
| | - Mark G Humphrey
- School of Chemical and Material Engineering, Jiangnan University, Wuxi 214122, Jiangsu Province, China. and Research School of Chemistry, Australian National University, Canberra, ACT 2601, Australia
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Effect of Planarity of Aromatic Rings Appended to o-Carborane on Photophysical Properties: A Series of o-Carboranyl Compounds Based on 2-Phenylpyridine- and 2-(Benzo[b]thiophen-2-yl)pyridine. Molecules 2019; 24:molecules24010201. [PMID: 30621119 PMCID: PMC6337515 DOI: 10.3390/molecules24010201] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2018] [Revised: 12/31/2018] [Accepted: 01/03/2019] [Indexed: 11/16/2022] Open
Abstract
Herein, we investigated the effect of ring planarity by fully characterizing four pyridine-based o-carboranyl compounds. o-Carborane was introduced to the C4 position of the pyridine rings of 2-phenylpyridine and 2-(benzo[b]thiophen-2-yl)pyridine (CB1 and CB2, respectively), and the compounds were subsequently borylated to obtain the corresponding C∧N-chelated compounds CB1B and CB2B. Single-crystal X-ray diffraction analysis of the molecular structures of CB2 and CB2B confirmed that o-carborane is appended to the aryl moiety. In photoluminescence experiments, CB2, but not CB1, showed an intense emission, assignable to intramolecular charge transfer (ICT) transition between the aryl and o-carborane moieties, in both solution and film states. On the other hand, in both solution and film states, CB1B and CB2B demonstrated a strong emission, originating from π-π * transition in the aryl groups, that tailed off to 650 nm owing to the ICT transition. All intramolecular electronic transitions in these o-carboranyl compounds were verified by theoretical calculations. These results distinctly suggest that the planarity of the aryl groups have a decisive effect on the efficiency of the radiative decay due to the ICT transition.
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46
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Martin KL, Krishnamurthy A, Strahan J, Young ER, Carter KR. Excited State Characterization of Carborane-Containing Poly(dihexyl fluorene)s. J Phys Chem A 2019; 123:1701-1709. [DOI: 10.1021/acs.jpca.8b07955] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- K. Lindsey Martin
- Department of Polymer Science and Engineering, University of Massachusetts—Amherst, 120 Governors Drive, Amherst, Massachusetts 01003, United States
| | - Aditi Krishnamurthy
- Department of Chemistry, Amherst College, P.O. Box 5000, Amherst, Massachusetts 01002, United States
| | - John Strahan
- Department of Chemistry, Amherst College, P.O. Box 5000, Amherst, Massachusetts 01002, United States
| | - Elizabeth R. Young
- Department of Chemistry, Lehigh University, 6 East Packer Avenue, Bethlehem, Pennsylvania 18015, United States
| | - Kenneth R. Carter
- Department of Polymer Science and Engineering, University of Massachusetts—Amherst, 120 Governors Drive, Amherst, Massachusetts 01003, United States
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47
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Choi S, Lee HE, Ryu CH, Lee J, Lee J, Yoon M, Kim Y, Park MH, Lee KM, Kim M. Synthesis of o-carborane-functionalized metal–organic frameworks through ligand exchanges for aggregation-induced emission in the solid state. Chem Commun (Camb) 2019; 55:11844-11847. [DOI: 10.1039/c9cc06386b] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
o-Carborane-functionalized MOFs were successfully prepared through ligand exchanges, and the PL were drastically shifted by AIE in the solid state.
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Affiliation(s)
- Sangdon Choi
- Department of Chemistry and BK21Plus Research Team
- Chungbuk National University
- Cheongju
- Korea
| | - Ha-Eun Lee
- Department of Chemistry and BK21Plus Research Team
- Chungbuk National University
- Cheongju
- Korea
| | - Chan Hee Ryu
- Department of Chemistry
- Institute of Molecular Science and Fusion Technology
- Kangwon National University
- Chuncheon 24341
- Korea
| | - Jooyeon Lee
- Department of Chemistry and BK21Plus Research Team
- Chungbuk National University
- Cheongju
- Korea
| | - Jihyun Lee
- Department of Nanochemistry, Gachon University
- Sungnam 13120
- Korea
| | - Minyoung Yoon
- Department of Chemistry
- Kyungpook National University
- Daegu 41566
- Korea
| | - Youngjo Kim
- Department of Chemistry and BK21Plus Research Team
- Chungbuk National University
- Cheongju
- Korea
| | - Myung Hwan Park
- Department of Chemistry Education
- Chungbuk National University
- Cheongju
- Korea
| | - Kang Mun Lee
- Department of Chemistry
- Institute of Molecular Science and Fusion Technology
- Kangwon National University
- Chuncheon 24341
- Korea
| | - Min Kim
- Department of Chemistry and BK21Plus Research Team
- Chungbuk National University
- Cheongju
- Korea
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48
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Jin H, Bae HJ, Kim S, Lee JH, Hwang H, Park MH, Lee KM. 2-Phenylpyridine- and 2-(benzo[b]thiophen-2-yl)pyridine-based o-carboranyl compounds: impact of the structural formation of aromatic rings on photophysical properties. Dalton Trans 2019; 48:1467-1476. [DOI: 10.1039/c8dt04367a] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
2-Phenylpyridine and 2-(benzo[b]thiophen-2-yl)pyridine-based o-carboranyl compounds showed intriguing emission that depended on the structural formation.
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Affiliation(s)
- Hyomin Jin
- Department of Chemistry and Institute for Molecular Science and Fusion Technology
- Kangwon National University
- Gangwon 24341
- Republic of Korea
| | - Hye Jin Bae
- Department of Chemistry
- KAIST
- Daejeon 34142
- Republic of Korea
| | - Seonah Kim
- Department of Chemistry and Institute for Molecular Science and Fusion Technology
- Kangwon National University
- Gangwon 24341
- Republic of Korea
| | - Ji Hye Lee
- Department of Chemistry and Institute for Molecular Science and Fusion Technology
- Kangwon National University
- Gangwon 24341
- Republic of Korea
| | - Hyonseok Hwang
- Department of Chemistry and Institute for Molecular Science and Fusion Technology
- Kangwon National University
- Gangwon 24341
- Republic of Korea
| | - Myung Hwan Park
- Department of Chemistry Education
- Chungbuk National University
- Chungbuk 28644
- Republic of Korea
| | - Kang Mun Lee
- Department of Chemistry and Institute for Molecular Science and Fusion Technology
- Kangwon National University
- Gangwon 24341
- Republic of Korea
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49
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Nghia NV, Oh J, Sujith S, Jung J, Lee MH. Tuning the photophysical properties of carboranyl luminophores by closo- to nido-carborane conversion and application to OFF-ON fluoride sensing. Dalton Trans 2018; 47:17441-17449. [PMID: 30488927 DOI: 10.1039/c8dt03771j] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
A family of closo-carborane-appended luminophores (closo-OXD1-2 and closo-DPS1-2) in which 2-R-o-carboranes (R = H, Me) are attached to the diphenyl-1,3,4-oxadiazole (OXD) or diphenyl-sulfone (DPS) acceptor groups were prepared and characterized. Deboronation of the closo-carborane cage produced the corresponding nido-carboranyl luminophores (nido-OXD1-2 and nido-DPS1-2). Whereas the closo-compounds were poorly emissive in THF (ΦPL < 0.01), the nido-luminophores exhibited an intense fluorescence with good quantum yields (ΦPL = 0.1-0.45). Electrochemical studies showed that while the closo-OXD and -DPS compounds displayed only carborane-centred, quasi-reversible reduction, the nido-compounds exhibited the typical features for nido-carborane-centred, irreversible oxidation and acceptor-centred, reversible reduction. Theoretical studies suggested that while the 1ππ* state of closo-compounds is nonemissive due to the contribution of closo-carborane to the LUMO in the S1 excited state, the intramolecular charge transfer (ICT) state from the nido-carborane to acceptor moieties in nido-compounds leads to an efficient fluorescence. Finally, THF solutions of closo-OXD1 and -DPS1 showed strong fluorescence upon the addition of fluoride anions under mild heating, but were intact to other anions, including cyanide, allowing the selective OFF-ON fluorescence sensing of fluoride.
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Affiliation(s)
- Nguyen Van Nghia
- Department of Chemistry, University of Ulsan, Ulsan 44610, Republic of Korea.
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50
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Exploiting the Electronic Tuneability of Carboranes as Supports for Frustrated Lewis Pairs. Molecules 2018; 23:molecules23123099. [PMID: 30486434 PMCID: PMC6321043 DOI: 10.3390/molecules23123099] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2018] [Revised: 11/22/2018] [Accepted: 11/23/2018] [Indexed: 11/16/2022] Open
Abstract
The first example of a carborane with a catecholborolyl substituent, [1-Bcat-2-Ph-closo-1,2-C₂B10H10] (1), has been prepared and characterized and shown to act as the Lewis acid component of an intermolecular frustrated Lewis pair in catalyzing a Michael addition. In combination with B(C₆F₅)₃ the C-carboranylphosphine [1-PPh₂-closo-1,2-C₂B10H11] (IVa) is found to be comparable with PPh₂(C₆F₅) in its ability to catalyze hydrosilylation, whilst the more strongly basic B-carboranylphosphine [9-PPh₂-closo-1,7-C₂B10H11] (V) is less effective and the very weakly basic species [μ-2,2'-PPh-{1-(1'-1',2'-closo-C₂B10H10)-1,2-closo-C₂B10H10}] (IX) is completely ineffective. Base strengths are rank-ordered via measurement of the ¹J 31P-77Se coupling constants of the phosphineselenides [1-SePPh₂-closo-1,2-C₂B10H11] (2), [9-SePPh₂-closo-1,7-C₂B10H11] (3), and [SePPh₂(C₆F₅)] (4).
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