1
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Zacharias H, Begum A, Han J, Bartholome TA, Marder TB, Martin CD. Synthesis of phenanthrylboroles and formal nitrene insertion to access azaborapyrenes. Chem Commun (Camb) 2024. [PMID: 39072482 DOI: 10.1039/d4cc02863e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/30/2024]
Abstract
Extended conjugation has been introduced into boroles but only on the 2,3- or 4,5-positions of the central BC4 core. In this work we synthesize phenanthrylboroles that also have conjugation on the 3,4-positions and demonstrate their insertion reactivity with azides to furnish B,N-analogues of pyrene.
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Affiliation(s)
- Harie Zacharias
- Department of Chemistry and Biochemistry, Baylor University, One Bear Place #97348, Waco, Texas 76798, USA.
| | - Ayesha Begum
- Department of Chemistry and Biochemistry, Baylor University, One Bear Place #97348, Waco, Texas 76798, USA.
| | - Jianhua Han
- Institut für Anorganische Chemie, and Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - Tyler A Bartholome
- Department of Chemistry and Biochemistry, Baylor University, One Bear Place #97348, Waco, Texas 76798, USA.
| | - Todd B Marder
- Institut für Anorganische Chemie, and Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Würzburg, Am Hubland, 97074 Würzburg, Germany
| | - Caleb D Martin
- Department of Chemistry and Biochemistry, Baylor University, One Bear Place #97348, Waco, Texas 76798, USA.
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2
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Akram MO, Martin CD, Dutton JL. The Effect of Carborane Substituents on the Lewis Acidity of Boranes. Inorg Chem 2023; 62:13495-13504. [PMID: 37560972 DOI: 10.1021/acs.inorgchem.3c01872] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/11/2023]
Abstract
The Lewis acidity of primary, secondary, and tertiary boranes with phenyl, pentafluorophenyl, and all three isomers of the C-substituted icosahedral carboranes (ortho, meta, and para) was investigated by computing their fluoride, hydride, and ammonia affinities as well as their global electrophilicity indices and LUMO energies. From these calculations, it was determined that the substituent effects on the Lewis acidity of these boranes follow the trend of ortho-carborane > meta-carborane > para-carborane > C6F5 > C6H5.
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Affiliation(s)
- Manjur O Akram
- Baylor University, Department of Chemistry and Biochemistry, One Bear Place #97348, Waco, Texas 76798, United States
| | - Caleb D Martin
- Baylor University, Department of Chemistry and Biochemistry, One Bear Place #97348, Waco, Texas 76798, United States
| | - Jason L Dutton
- La Trobe University, Department of Chemistry, La Trobe Institute for Molecular Science, Melbourne, Victoria 3086,Australia
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3
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Li Y, Shen YH, Esper AM, Tidwell JR, Veige AS, Martin CD. Probing borafluorene B-C bond insertion with gold acetylide and azide. Dalton Trans 2023; 52:668-674. [PMID: 36537567 DOI: 10.1039/d2dt03672j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The reaction of Ph3PAuN3 with 9-Ph-9-borafluorene resulted in complexation of the azide to boron while a gold acetylide reacted with 9-Ph-9-borafluorene to insert the acetylide carbon to access a six-membered boracycle with an exocyclic double bond.
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Affiliation(s)
- Yijie Li
- Baylor University, Department of Chemistry and Biochemistry, One Bear Place #97348, Waco, TX 76798, USA.
| | - Yu-Hsuan Shen
- University of Florida, Department of Chemistry, Center for Catalysis, Gainesville, FL 32611, USA
| | - Alec M Esper
- University of Florida, Department of Chemistry, Center for Catalysis, Gainesville, FL 32611, USA
| | - John R Tidwell
- Baylor University, Department of Chemistry and Biochemistry, One Bear Place #97348, Waco, TX 76798, USA.
| | - Adam S Veige
- University of Florida, Department of Chemistry, Center for Catalysis, Gainesville, FL 32611, USA
| | - Caleb D Martin
- Baylor University, Department of Chemistry and Biochemistry, One Bear Place #97348, Waco, TX 76798, USA.
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4
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Krebs J, Häfner A, Fuchs S, Guo X, Rauch F, Eichhorn A, Krummenacher I, Friedrich A, Ji L, Finze M, Lin Z, Braunschweig H, Marder TB. Backbone-controlled LUMO energy induces intramolecular C-H activation in ortho-bis-9-borafluorene-substituted phenyl and o-carboranyl compounds leading to novel 9,10-diboraanthracene derivatives. Chem Sci 2022; 13:14165-14178. [PMID: 36540825 PMCID: PMC9728567 DOI: 10.1039/d2sc06057d] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2022] [Accepted: 11/05/2022] [Indexed: 08/11/2023] Open
Abstract
The choice of backbone linker for two ortho-bis-(9-borafluorene)s has a great influence on the LUMO located at the boron centers and, therefore, the reactivity of the respective compounds. Herein, we report the room temperature rearrangement of 1,2-bis-(9-borafluorenyl)-ortho-carborane, C2B10H10-1,2-[B(C12H8)]2 ([2a]) featuring o-carborane as the inorganic three-dimensional backbone and the synthesis of 1,2-bis-(9-borafluorenyl)benzene, C6H4-1,2-[B(C12H8)]2 (2b), its phenylene analog. DFT calculations on the transition state for the rearrangement support an intramolecular C-H bond activation process via an SEAr-like mechanism in [2a], and predicted that the same rearrangement would take place in 2b, but at elevated temperatures, which indeed proved to be the case. The rearrangement gives access to 3a and 3b as dibora-benzo[a]fluoroanthene isomers, a form of diboron polycyclic aromatic hydrocarbon (PAH) that had yet to be explored. The isolated compounds 2b, 3a, and 3b were fully characterized by NMR, HRMS, cyclic voltammetry (CV), single-crystal X-ray diffraction analysis, and photophysical measurements, supported by DFT and TD-DFT calculations.
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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
| | - Alena Häfner
- Institute for Inorganic Chemistry and Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Germany
| | - Sonja Fuchs
- Institute for Inorganic Chemistry and Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Germany
| | - Xueying Guo
- Department of Chemistry, The Hong Kong University of Science and Technology Clear Water Bay Hong Kong
| | - Florian Rauch
- Institute for Inorganic Chemistry and Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Germany
| | - Antonius Eichhorn
- 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
| | - Lei Ji
- Institute for Inorganic Chemistry and Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Germany
- Frontiers Science Center for Flexible Electronics, Xi'an Institute of Flexible Electronics (IFE), Northwestern Polytechnical University 127 West Youyi Road Xi'an Shaanxi P. R. China
| | - Maik Finze
- Institute for Inorganic Chemistry and Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Germany
| | - Zhenyang Lin
- Department of Chemistry, The Hong Kong University of Science and Technology Clear Water Bay Hong Kong
| | - Holger Braunschweig
- Institute for Inorganic Chemistry and Institute for Sustainable Chemistry & Catalysis with Boron, Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Germany
| | - 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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5
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Akram MO, Tidwell JR, Dutton JL, Wilson DJD, Molino A, Martin CD. Accessing Boron-Doped Pentaphene Analogues from 12-Boradibenzofluorene. Inorg Chem 2022; 61:9595-9604. [PMID: 35696381 DOI: 10.1021/acs.inorgchem.2c00930] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Borole-doped polycyclic aromatic hydrocarbons (PAHs) have garnered attention in recent years due to their attractive photophysical properties and potential utility in electronic devices. In this work, a borole-doped PAH, 12-boradibenzofluorene, is synthesized and formal intermolecular nitrene and oxygen atom insertion reactions were employed to access 1,2-azaborine- and 1,2-oxaborine-containing analogues of the carbonaceous PAH pentaphene. Iodosobenzene is established as a versatile reagent for oxygen atom insertion reactions into a variety of borole species to access 1,2-oxaborine systems.
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Affiliation(s)
- Manjur O Akram
- Department of Chemistry and Biochemistry, Baylor University, One Bear Place #97348, Waco, Texas 76798, United States
| | - John R Tidwell
- Department of Chemistry and Biochemistry, Baylor University, One Bear Place #97348, Waco, Texas 76798, United States
| | - Jason L Dutton
- Department of Biochemistry and Chemistry, La Trobe Institute for Molecular Science, La Trobe University, Melbourne 3086, Victoria, Australia
| | - David J D Wilson
- Department of Biochemistry and Chemistry, La Trobe Institute for Molecular Science, La Trobe University, Melbourne 3086, Victoria, Australia
| | - Andrew Molino
- Department of Biochemistry and Chemistry, La Trobe Institute for Molecular Science, La Trobe University, Melbourne 3086, Victoria, Australia
| | - Caleb D Martin
- Department of Chemistry and Biochemistry, Baylor University, One Bear Place #97348, Waco, Texas 76798, United States
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6
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Tsukada T, Shoji Y, Takenouchi K, Taka H, Fukushima T. A carbon-functionality-appended diborylacetylene available for a component of organic synthesis and OLEDs. Chem Commun (Camb) 2022; 58:4973-4976. [PMID: 35373797 DOI: 10.1039/d2cc01159j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We present new 1,2-diborylacetylene derivatives with planar 9-oxa-10-boraanthracene termini, which display excellent stability to allow usual handling and even thermal evaporation for the preparation of thin films for OLEDs, and also undergo typical reactions of alkynes such as the Diels-Alder reaction.
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Affiliation(s)
- Tetsuyoshi Tsukada
- Laboratory for Chemistry and Life Science, Institute of Innovative Research, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 226-8503, Japan. .,Department of Chemical Science and Engineering, School of Materials and Chemical Technology, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 226-8503, Japan
| | - Yoshiaki Shoji
- Laboratory for Chemistry and Life Science, Institute of Innovative Research, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 226-8503, Japan. .,Department of Chemical Science and Engineering, School of Materials and Chemical Technology, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 226-8503, Japan
| | - Kumiko Takenouchi
- Laboratory for Chemistry and Life Science, Institute of Innovative Research, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 226-8503, Japan.
| | - Hideo Taka
- Konica Minolta, Ishikawa-cho, Hachioji, Tokyo 192-8505, Japan
| | - Takanori Fukushima
- Laboratory for Chemistry and Life Science, Institute of Innovative Research, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 226-8503, Japan. .,Department of Chemical Science and Engineering, School of Materials and Chemical Technology, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama 226-8503, Japan
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7
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Shoji Y, Kashida J, Fukushima T. Bringing out the potential of organoboron compounds by designing the chemical bonds and spaces around boron. Chem Commun (Camb) 2022; 58:4420-4434. [DOI: 10.1039/d2cc00653g] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Since the structures, reactivity and properties of organoboron compounds stem from the electron deficiency and low electronegativity of boron, the design of the chemical bonds attached to boron as well...
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8
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Murata Y, Matsunagi K, Kashida J, Shoji Y, Özen C, Maeda S, Fukushima T. Observation of Borane–Olefin Proximity Interaction Governing the Structure and Reactivity of Boron‐Containing Macrocycles. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202103512] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Yukihiro Murata
- Laboratory for Chemistry and Life Science, Institute of Innovative Research Tokyo Institute of Technology 4259 Nagatsuta, Midori-ku Yokohama 226-8503 Japan
- Department of Chemical Science and Engineering School of Materials and Chemical Technology Tokyo Institute of Technology 4259 Nagatsuta, Midori-ku Yokohama 226-8502 Japan
| | - Kenta Matsunagi
- Laboratory for Chemistry and Life Science, Institute of Innovative Research Tokyo Institute of Technology 4259 Nagatsuta, Midori-ku Yokohama 226-8503 Japan
- Department of Chemical Science and Engineering School of Materials and Chemical Technology Tokyo Institute of Technology 4259 Nagatsuta, Midori-ku Yokohama 226-8502 Japan
| | - Junki Kashida
- Laboratory for Chemistry and Life Science, Institute of Innovative Research Tokyo Institute of Technology 4259 Nagatsuta, Midori-ku Yokohama 226-8503 Japan
- Department of Chemical Science and Engineering School of Materials and Chemical Technology Tokyo Institute of Technology 4259 Nagatsuta, Midori-ku Yokohama 226-8502 Japan
| | - Yoshiaki Shoji
- Laboratory for Chemistry and Life Science, Institute of Innovative Research Tokyo Institute of Technology 4259 Nagatsuta, Midori-ku Yokohama 226-8503 Japan
- Department of Chemical Science and Engineering School of Materials and Chemical Technology Tokyo Institute of Technology 4259 Nagatsuta, Midori-ku Yokohama 226-8502 Japan
| | - Cihan Özen
- Institute for Chemical Reaction Design and Discovery, (WPI-ICReDD) Hokkaido University Sapporo 060-8510 Japan
- Department of Chemistry Hokkaido University Sapporo 060-8510 Japan
| | - Satoshi Maeda
- Institute for Chemical Reaction Design and Discovery, (WPI-ICReDD) Hokkaido University Sapporo 060-8510 Japan
- Department of Chemistry Hokkaido University Sapporo 060-8510 Japan
| | - Takanori Fukushima
- Laboratory for Chemistry and Life Science, Institute of Innovative Research Tokyo Institute of Technology 4259 Nagatsuta, Midori-ku Yokohama 226-8503 Japan
- Department of Chemical Science and Engineering School of Materials and Chemical Technology Tokyo Institute of Technology 4259 Nagatsuta, Midori-ku Yokohama 226-8502 Japan
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9
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Murata Y, Matsunagi K, Kashida J, Shoji Y, Özen C, Maeda S, Fukushima T. Observation of Borane-Olefin Proximity Interaction Governing the Structure and Reactivity of Boron-Containing Macrocycles. Angew Chem Int Ed Engl 2021; 60:14630-14635. [PMID: 33860607 DOI: 10.1002/anie.202103512] [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: 03/10/2021] [Indexed: 11/06/2022]
Abstract
While attractive interactions between borane and olefin have been postulated to trigger various boron-mediated organic transformations, proximity structures of these functional groups, other than the formation of weak van der Waals complexes, have never been directly observed. Here we show that a close intramolecular borane-olefin interaction operates in macrocyclic systems containing borane and olefinic groups obtained by multi-step 1,2-carboboration between a strained alkyne and 9-borafluorene derivatives. Depending on Lewis acidity of the borane moiety and the size of the macrocycles, the magnitude of interaction changes, resulting in different reaction modes. The whole picture of the multi-step reactions has been revealed experimentally with theoretical supports. The present finding may not only provide a deeper understanding of the fundamental boron-mediated interaction but also lead to the development of new organic transformations involving molecular activation by boranes.
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Affiliation(s)
- Yukihiro Murata
- Laboratory for Chemistry and Life Science, Institute of Innovative Research, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama, 226-8503, Japan.,Department of Chemical Science and Engineering, School of Materials and Chemical Technology, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama, 226-8502, Japan
| | - Kenta Matsunagi
- Laboratory for Chemistry and Life Science, Institute of Innovative Research, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama, 226-8503, Japan.,Department of Chemical Science and Engineering, School of Materials and Chemical Technology, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama, 226-8502, Japan
| | - Junki Kashida
- Laboratory for Chemistry and Life Science, Institute of Innovative Research, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama, 226-8503, Japan.,Department of Chemical Science and Engineering, School of Materials and Chemical Technology, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama, 226-8502, Japan
| | - Yoshiaki Shoji
- Laboratory for Chemistry and Life Science, Institute of Innovative Research, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama, 226-8503, Japan.,Department of Chemical Science and Engineering, School of Materials and Chemical Technology, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama, 226-8502, Japan
| | - Cihan Özen
- Institute for Chemical Reaction Design and Discovery, (WPI-ICReDD), Hokkaido University, Sapporo, 060-8510, Japan.,Department of Chemistry, Hokkaido University, Sapporo, 060-8510, Japan
| | - Satoshi Maeda
- Institute for Chemical Reaction Design and Discovery, (WPI-ICReDD), Hokkaido University, Sapporo, 060-8510, Japan.,Department of Chemistry, Hokkaido University, Sapporo, 060-8510, Japan
| | - Takanori Fukushima
- Laboratory for Chemistry and Life Science, Institute of Innovative Research, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama, 226-8503, Japan.,Department of Chemical Science and Engineering, School of Materials and Chemical Technology, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama, 226-8502, Japan
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10
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Su X, Bartholome TA, Tidwell JR, Pujol A, Yruegas S, Martinez JJ, Martin CD. 9-Borafluorenes: Synthesis, Properties, and Reactivity. Chem Rev 2021; 121:4147-4192. [DOI: 10.1021/acs.chemrev.0c01068] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Affiliation(s)
- Xiaojun Su
- Department of Chemistry and Biochemistry, Baylor University, One Bear Place #97348, Waco, Texas 76798, United States
| | - Tyler A. Bartholome
- Department of Chemistry and Biochemistry, Baylor University, One Bear Place #97348, Waco, Texas 76798, United States
| | - John R. Tidwell
- Department of Chemistry and Biochemistry, Baylor University, One Bear Place #97348, Waco, Texas 76798, United States
| | - Alba Pujol
- Department of Chemistry and Biochemistry, Baylor University, One Bear Place #97348, Waco, Texas 76798, United States
| | - Sam Yruegas
- Department of Chemistry and Biochemistry, Baylor University, One Bear Place #97348, Waco, Texas 76798, United States
| | - Jesse J. Martinez
- Department of Chemistry and Biochemistry, Baylor University, One Bear Place #97348, Waco, Texas 76798, United States
| | - Caleb D. Martin
- Department of Chemistry and Biochemistry, Baylor University, One Bear Place #97348, Waco, Texas 76798, United States
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11
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Shoji Y, Kashida J, Fukushima T. Organic Transformations Using Electron-Deficient Boron Compounds. J SYN ORG CHEM JPN 2020. [DOI: 10.5059/yukigoseikyokaishi.78.190] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Yoshiaki Shoji
- Laboratory for Chemistry and Life Science (CLS), Institute of Innovative Research, Tokyo Institute of Technology
| | | | - Takanori Fukushima
- Laboratory for Chemistry and Life Science (CLS), Institute of Innovative Research, Tokyo Institute of Technology
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12
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Yang W, Krantz KE, Freeman LA, Dickie DA, Molino A, Frenking G, Pan S, Wilson DJD, Gilliard RJ. Persistent Borafluorene Radicals. Angew Chem Int Ed Engl 2020; 59:3850-3854. [PMID: 31816143 PMCID: PMC7064902 DOI: 10.1002/anie.201909627] [Citation(s) in RCA: 64] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2019] [Revised: 11/19/2019] [Indexed: 01/23/2023]
Abstract
N‐Heterocyclic carbene (NHC)‐ and cyclic (alkyl)(amino)carbene (CAAC)‐stabilized borafluorene radicals have been isolated and characterized by elemental analysis, single‐crystal X‐ray diffraction, UV/Vis absorption, cyclic voltammetry (CV), electron paramagnetic resonance (EPR) spectroscopy, and theoretical studies. Both the CAAC–borafluorene radical (2) and the NHC–borafluorene radical (4) have a considerable amount of spin density localized on the boron atoms (0.322 for 2 and 0.369 for 4). In compound 2, the unpaired electron is also partly delocalized over the CAAC ligand carbeneC and N atoms. However, the unpaired electron in compound 4 mainly resides throughout the borafluorene π‐system, with significantly less delocalization over the NHC ligand. These results highlight the Lewis base dependent electrostructural tuning of materials‐relevant radicals. Notably, this is the first report of crystalline borafluorene radicals, and these species exhibit remarkable solid‐state and solution stability.
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Affiliation(s)
- Wenlong Yang
- Department of Chemistry, University of Virginia, 409 McCormick Rd./ PO Box 400319, Charlottesville, VA, 22904, USA
| | - Kelsie E Krantz
- Department of Chemistry, University of Virginia, 409 McCormick Rd./ PO Box 400319, Charlottesville, VA, 22904, USA
| | - Lucas A Freeman
- Department of Chemistry, University of Virginia, 409 McCormick Rd./ PO Box 400319, Charlottesville, VA, 22904, USA
| | - Diane A Dickie
- Department of Chemistry, University of Virginia, 409 McCormick Rd./ PO Box 400319, Charlottesville, VA, 22904, USA
| | - Andrew Molino
- Department of Chemistry and Physics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, 3086, Victoria, Australia
| | - Gernot Frenking
- Fachbereich Chemie, Philipps-Universität Marburg, Hans-Meerwein-Straße, 35043, Marburg, Germany
| | - Sudip Pan
- Fachbereich Chemie, Philipps-Universität Marburg, Hans-Meerwein-Straße, 35043, Marburg, Germany
| | - David J D Wilson
- Department of Chemistry and Physics, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, 3086, Victoria, Australia
| | - Robert J Gilliard
- Department of Chemistry, University of Virginia, 409 McCormick Rd./ PO Box 400319, Charlottesville, VA, 22904, USA
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13
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Yang W, Krantz KE, Freeman LA, Dickie DA, Molino A, Frenking G, Pan S, Wilson DJD, Gilliard RJ. Persistent Borafluorene Radicals. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.201909627] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Wenlong Yang
- Department of Chemistry University of Virginia 409 McCormick Rd./ PO Box 400319 Charlottesville VA 22904 USA
| | - Kelsie E. Krantz
- Department of Chemistry University of Virginia 409 McCormick Rd./ PO Box 400319 Charlottesville VA 22904 USA
| | - Lucas A. Freeman
- Department of Chemistry University of Virginia 409 McCormick Rd./ PO Box 400319 Charlottesville VA 22904 USA
| | - Diane A. Dickie
- Department of Chemistry University of Virginia 409 McCormick Rd./ PO Box 400319 Charlottesville VA 22904 USA
| | - Andrew Molino
- Department of Chemistry and Physics La Trobe Institute for Molecular Science La Trobe University Melbourne 3086 Victoria Australia
| | - Gernot Frenking
- Fachbereich Chemie Philipps-Universität Marburg Hans-Meerwein-Straße 35043 Marburg Germany
| | - Sudip Pan
- Fachbereich Chemie Philipps-Universität Marburg Hans-Meerwein-Straße 35043 Marburg Germany
| | - David J. D. Wilson
- Department of Chemistry and Physics La Trobe Institute for Molecular Science La Trobe University Melbourne 3086 Victoria Australia
| | - Robert J. Gilliard
- Department of Chemistry University of Virginia 409 McCormick Rd./ PO Box 400319 Charlottesville VA 22904 USA
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14
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Ishiwari F, Ofuchi M, Inoue K, Sei Y, Fukushima T. Switching of the conformational flexibility of a diazacyclooctane-containing ladder polymer by coordination and elimination of a Lewis acid. Polym Chem 2020. [DOI: 10.1039/c9py01104h] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
We report the first system of ladder polymers capable of interconversion between rigid and flexible conformations by coordination and elimination of a Lewis acid (BPh2Cl) on diazacyclooctane units in the main chain.
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Affiliation(s)
- Fumitaka Ishiwari
- Laboratory for Chemistry and Life Science
- Institute of Innovative Research
- Tokyo Institute of Technology
- Yokohama 226-8503
- Japan
| | - Momoko Ofuchi
- Laboratory for Chemistry and Life Science
- Institute of Innovative Research
- Tokyo Institute of Technology
- Yokohama 226-8503
- Japan
| | - Keiki Inoue
- Laboratory for Chemistry and Life Science
- Institute of Innovative Research
- Tokyo Institute of Technology
- Yokohama 226-8503
- Japan
| | - Yoshihisa Sei
- Suzukakedai Materials Analysis Division
- Technical Department
- Tokyo Institute of Technology
- Yokohama 226-8503
- Japan
| | - Takanori Fukushima
- Laboratory for Chemistry and Life Science
- Institute of Innovative Research
- Tokyo Institute of Technology
- Yokohama 226-8503
- Japan
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15
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Abstract
Most of the chemical and biological processes involving the fixation and transformation of small molecules have long been exclusive for metal complexes. Meanwhile, the last decades have seen a significant advance in main group chemistry that mimics transition-metal complexes, among which various boron-containing systems have been successful in mediating the small molecule activation. In this review, we focus on boron-containing heterocycles enabling the activation of σ- and π-bonds in small molecules, in conjunction with the proposed mechanisms.
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Affiliation(s)
- Yuanting Su
- Division of Chemistry and Biological Chemistry, School of Physical and Mathematical Sciences, Nanyang Technological University, Nanyang Link 21, Singapore 637371, Singapore.
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16
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Bartholome TA, Bluer KR, Martin CD. Successive carbene insertion into 9-phenyl-9-borafluorene. Dalton Trans 2019; 48:6319-6322. [PMID: 30942222 DOI: 10.1039/c9dt01032g] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
The reactions of 9-phenyl-9-borafluorene with trimethylsilyldiazomethane in a 1 : 1 and 1 : 2 stoichiometry furnished the corresponding BC5 and BC6 heterocycles via the formal insertion of one and two carbene units.
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Affiliation(s)
- Tyler A Bartholome
- Baylor University, Department of Chemistry and Biochemistry, One Bear Place #97348, Waco, TX 76798, USA.
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