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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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2
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Mears KL, Kutzleb MA, Stennett CR, Fettinger JC, Kaseman DC, Yu P, Vasko P, Power PP. Terpene dispersion energy donor ligands in borane complexes. Chem Commun (Camb) 2022; 58:9910-9913. [PMID: 35979664 DOI: 10.1039/d2cc04203g] [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
Structural characterization of the complex [B(β-pinane)3] (1) reveals non-covalent H⋯H contacts that are consistent with the generation of London dispersion energies involving the β-pinane ligand frameworks. The homolytic fragmentations of 1, and camphane and sabinane analogues ([B(camphane)3] (2) and [B(sabinane)3] (3)) were studied computationally. Isodesmic exchange results showed that London dispersion interactions are highly dependent on the terpene's stereochemistry, with the β-pinane framework providing the greatest dispersion free energy (ΔG = -7.9 kcal mol-1) with Grimme's dispersion correction (D3BJ) employed. PMe3 was used to coordinate to [B(β-pinane)3], giving the complex [Me3P-B(β-pinane)3] (4), which displayed a dynamic coordination equilibrium in solution. The association process was found to be slightly endergonic at 302 K (ΔG = +0.29 kcal mol-1).
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Affiliation(s)
- Kristian L Mears
- Department of Chemistry, University of California, One Shields Avenue, Davis, CA 95616, USA.
| | - Michelle A Kutzleb
- Department of Chemistry, University of California, One Shields Avenue, Davis, CA 95616, USA.
| | - Cary R Stennett
- Department of Chemistry, University of California, One Shields Avenue, Davis, CA 95616, USA.
| | - James C Fettinger
- Department of Chemistry, University of California, One Shields Avenue, Davis, CA 95616, USA.
| | - Derrick C Kaseman
- Department of Chemistry, University of California, One Shields Avenue, Davis, CA 95616, USA.
| | - Ping Yu
- Department of Chemistry, University of California, One Shields Avenue, Davis, CA 95616, USA.
| | - Petra Vasko
- Department of Chemistry, University of Helsinki, PO Box 55 (A. I. Virtasen aukio 1), 00014, Finland.
| | - Philip P Power
- Department of Chemistry, University of California, One Shields Avenue, Davis, CA 95616, USA.
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3
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Norwine EE, Kiernicki JJ, Zeller M, Szymczak NK. Distinct Reactivity Modes of a Copper Hydride Enabled by an Intramolecular Lewis Acid. J Am Chem Soc 2022; 144:15038-15046. [PMID: 35960993 PMCID: PMC10291504 DOI: 10.1021/jacs.2c02937] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
We disclose a 1,4,7-triazacyclononane (TACN) ligand featuring an appended boron Lewis acid. Metalation with Cu(I) affords a series of tetrahedral complexes including a boron-capped cuprous hydride. We demonstrate distinct reactivity modes as a function of chemical oxidation: hydride transfer to CO2 in the copper(I) state and oxidant-induced H2 evolution as well as alkyne reduction.
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Affiliation(s)
- Emily E. Norwine
- University of Michigan, 930 N. University, Ann Arbor, MI 48109 (USA)
| | - John J. Kiernicki
- University of Michigan, 930 N. University, Ann Arbor, MI 48109 (USA)
| | - Matthias Zeller
- H. C. Brown Laboratory, Purdue University, 560 Oval Dr., West Lafayette, IN 47907 (USA)
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4
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Abstract
In the last two decades, boron-based catalysis has been gaining increasing traction in the field of organic synthesis. The use of halogenated triarylboranes as main group Lewis acid catalysts is an attractive strategy. It has been applied in a growing number of transformations over the years, where they may perform comparably or even better than the gold standard catalysts. This review discusses methods of borane synthesis and cutting-edge boron-based Lewis acid catalysis, focusing especially on tris(pentafluorophenyl)-borane [B(C6F5)3], and other halogenated triarylboranes, highlighting how boron Lewis acids employed as catalysts can unlock a plethora of unprecedented chemical transformations or improve the efficiency of existing reactions.
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5
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Chen X, Meng G, Liao G, Rauch F, He J, Friedrich A, Marder TB, Wang N, Chen P, Wang S, Yin X. Highly Emissive 9-Borafluorene Derivatives: Synthesis, Photophysical Properties and Device Fabrication. Chemistry 2021; 27:6274-6282. [PMID: 33496983 PMCID: PMC8048904 DOI: 10.1002/chem.202005185] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2020] [Indexed: 12/15/2022]
Abstract
A series of 9-borafluorene derivatives, functionalised with electron-donating groups, have been prepared. Some of these 9-borafluorene compounds exhibit strong yellowish emission in solution and in the solid state with relatively high quantum yields (up to 73.6 % for FMesB-Cz as a neat film). The results suggest that the highly twisted donor groups suppress charge transfer, but the intrinsic photophysical properties of the 9-borafluorene systems remain. The new compounds showed enhanced stability towards the atmosphere, and exhibited excellent thermal stability, revealing their potential for application in materials science. Organic light-emitting diode (OLED) devices were fabricated with two of the highly emissive compounds, and they exhibited strong yellow-greenish electroluminescence, with a maximum luminance intensity of >22 000 cd m-2 . These are the first two examples of 9-borafluorene derivatives being used as light-emitting materials in OLED devices, and they have enabled us to achieve a balance between maintaining their intrinsic properties while improving their stability.
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Affiliation(s)
- Xing Chen
- Key Laboratory of Cluster ScienceMinistry of Education of ChinaBeijing Key Laboratory of Photoelectronic/Electrophotonic, Conversion MaterialsSchool of Chemistry and Chemical EngineeringBeijing Institute of Technology102488BeijingP.R. China
| | - Guoyun Meng
- Key Laboratory of Cluster ScienceMinistry of Education of ChinaBeijing Key Laboratory of Photoelectronic/Electrophotonic, Conversion MaterialsSchool of Chemistry and Chemical EngineeringBeijing Institute of Technology102488BeijingP.R. China
| | - Guanming Liao
- Key Laboratory of Cluster ScienceMinistry of Education of ChinaBeijing Key Laboratory of Photoelectronic/Electrophotonic, Conversion MaterialsSchool of Chemistry and Chemical EngineeringBeijing Institute of Technology102488BeijingP.R. China
| | - Florian Rauch
- Institut für Anorganische ChemieInstitute for Sustainable Chemistry & Catalysis with Boron (ICB)Julius-Maximilians-Universität WürzburgAm Hubland97074WürzburgGermany
| | - Jiang He
- Institut für Anorganische ChemieInstitute for Sustainable Chemistry & Catalysis with Boron (ICB)Julius-Maximilians-Universität WürzburgAm Hubland97074WürzburgGermany
| | - Alexandra Friedrich
- Institut für Anorganische ChemieInstitute for Sustainable Chemistry & Catalysis with Boron (ICB)Julius-Maximilians-Universität WürzburgAm Hubland97074WürzburgGermany
| | - Todd B. Marder
- Institut für Anorganische ChemieInstitute for Sustainable Chemistry & Catalysis with Boron (ICB)Julius-Maximilians-Universität WürzburgAm Hubland97074WürzburgGermany
| | - Nan Wang
- Key Laboratory of Cluster ScienceMinistry of Education of ChinaBeijing Key Laboratory of Photoelectronic/Electrophotonic, Conversion MaterialsSchool of Chemistry and Chemical EngineeringBeijing Institute of Technology102488BeijingP.R. China
| | - Pangkuan Chen
- Key Laboratory of Cluster ScienceMinistry of Education of ChinaBeijing Key Laboratory of Photoelectronic/Electrophotonic, Conversion MaterialsSchool of Chemistry and Chemical EngineeringBeijing Institute of Technology102488BeijingP.R. China
| | - Suning Wang
- Key Laboratory of Cluster ScienceMinistry of Education of ChinaBeijing Key Laboratory of Photoelectronic/Electrophotonic, Conversion MaterialsSchool of Chemistry and Chemical EngineeringBeijing Institute of Technology102488BeijingP.R. China
- Department of ChemistryQueen's UniversityKingstonONK7L3N6Canada
| | - Xiaodong Yin
- Key Laboratory of Cluster ScienceMinistry of Education of ChinaBeijing Key Laboratory of Photoelectronic/Electrophotonic, Conversion MaterialsSchool of Chemistry and Chemical EngineeringBeijing Institute of Technology102488BeijingP.R. China
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6
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Stoian C, Olaru M, Cucuiet TA, Kegyes KT, Sava A, Timoshkin AY, Raţ CI, Beckmann J. Bulky Polyfluorinated Terphenyldiphenylboranes: Water Tolerant Lewis Acids. Chemistry 2021; 27:4327-4331. [PMID: 33368648 PMCID: PMC7986919 DOI: 10.1002/chem.202005367] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2020] [Indexed: 11/23/2022]
Abstract
Protocols for the synthesis of the bulky polyfluorinated triarylboranes 2,6‐(C6F5)2C6F3B(C6F5)2 (1), 2,6‐(C6F5)2C6F3B[3,5‐(CF3)2C6H3] (2), 2,4,6‐(C6F5)3C6H2B(C6F5)2 (3), 2,4,6‐(C6F5)3C6H2B[3,5‐(CF3)2C6H3] (4) were developed. All boranes are water tolerant and according to the Gutmann‐Beckett method, 1–3 display Lewis acidities larger than that of the prominent B(C6F5)3.
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Affiliation(s)
- Corina Stoian
- Institut für Anorganische Chemie und Kristallographie, Universität Bremen, Leobener Straße 7, 28359, Bremen, Germany.,Department of Chemistry, Supramolecular Organic and Organometallic Chemistry Centre (SOOMCC), Faculty of Chemistry and Chemical Engineering, Babeş-Bolyai University, Arany János Steet 11, 400028, Cluj-Napoca, Romania
| | - Marian Olaru
- Institut für Anorganische Chemie und Kristallographie, Universität Bremen, Leobener Straße 7, 28359, Bremen, Germany
| | - Teodor A Cucuiet
- Department of Chemistry, Supramolecular Organic and Organometallic Chemistry Centre (SOOMCC), Faculty of Chemistry and Chemical Engineering, Babeş-Bolyai University, Arany János Steet 11, 400028, Cluj-Napoca, Romania
| | - Krisztina T Kegyes
- Department of Chemistry, Supramolecular Organic and Organometallic Chemistry Centre (SOOMCC), Faculty of Chemistry and Chemical Engineering, Babeş-Bolyai University, Arany János Steet 11, 400028, Cluj-Napoca, Romania
| | - Alexandru Sava
- Department of Chemistry, Supramolecular Organic and Organometallic Chemistry Centre (SOOMCC), Faculty of Chemistry and Chemical Engineering, Babeş-Bolyai University, Arany János Steet 11, 400028, Cluj-Napoca, Romania
| | - Alexey Y Timoshkin
- Institute of Chemistry, St. Petersburg State University, Universitetskaya emb. 7/9, 199034, St. Petersburg, Russia
| | - Ciprian I Raţ
- Department of Chemistry, Supramolecular Organic and Organometallic Chemistry Centre (SOOMCC), Faculty of Chemistry and Chemical Engineering, Babeş-Bolyai University, Arany János Steet 11, 400028, Cluj-Napoca, Romania
| | - Jens Beckmann
- Institut für Anorganische Chemie und Kristallographie, Universität Bremen, Leobener Straße 7, 28359, Bremen, Germany
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7
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Baser-Kirazli N, Lalancette RA, Jäkle F. Tuning the Donor−π–Acceptor Character of Arylborane–Arylamine Macrocycles. Organometallics 2021. [DOI: 10.1021/acs.organomet.0c00779] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Affiliation(s)
- Nurcan Baser-Kirazli
- Department of Chemistry, Rutgers University-Newark, 73 Warren Street, Newark, New Jersey 07102, United States
| | - Roger A. Lalancette
- Department of Chemistry, Rutgers University-Newark, 73 Warren Street, Newark, New Jersey 07102, United States
| | - Frieder Jäkle
- Department of Chemistry, Rutgers University-Newark, 73 Warren Street, Newark, New Jersey 07102, United States
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8
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He J, Rauch F, Finze M, Marder TB. (Hetero)arene-fused boroles: a broad spectrum of applications. Chem Sci 2020; 12:128-147. [PMID: 34163585 PMCID: PMC8178973 DOI: 10.1039/d0sc05676f] [Citation(s) in RCA: 46] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
(Hetero)arene-fused boroles are a class of compounds containing a 5-membered boron diene-ring. Based on their molecular framework, the (hetero)arene-fused boroles can be considered as boron-doped polycyclic antiaromatic hydrocarbons and are thus of great interest. Due to the vacant pz orbital on the 3-coordinate boron atom, the antiaromaticity and strain of the 5-membered borole ring, (hetero)arene-fused boroles possess strong electron accepting abilities and Lewis acidity. By functionalization, they can be tuned to optimize different properties for specific applications. Herein, we summarize synthetic methodologies, different strategies for their functionalization, and applications of (hetero)arene-fused boroles. (Hetero)arene-fused boroles, ‘antiaromatic’ 2n-electron π-systems, more stable and more functionalizable than boroles, offer greater potential for a variety of applications.![]()
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Affiliation(s)
- Jiang He
- Institute for Inorganic Chemistry and Institute for Sustainable Chemistry & Catalysis with Boron (ICB), Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Germany
| | - Florian Rauch
- Institute for Inorganic Chemistry and Institute for Sustainable Chemistry & Catalysis with Boron (ICB), Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Germany
| | - Maik Finze
- Institute for Inorganic Chemistry and Institute for Sustainable Chemistry & Catalysis with Boron (ICB), Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Germany
| | - Todd B Marder
- Institute for Inorganic Chemistry and Institute for Sustainable Chemistry & Catalysis with Boron (ICB), Julius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Germany
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9
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Škoch K, Daniliuc CG, Kehr G, Erker G. Using the FpXylBH 2•SMe 2 reagent for the regioselective synthesis of cyclic bis(alkenyl)boranes. Chem Commun (Camb) 2020; 56:12178-12181. [PMID: 32914803 DOI: 10.1039/d0cc05230b] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The reactive borane reagent FpXylBH2•SMe2 was prepared from 1,4-bis(trifluoromethyl)benzene by treatment with n-BuLi, followed by H3B·SMe2 and subsequent removal of hydride. It undergoes a regioselective hydroboration reaction with 1,2-bis(trimethylsilylethynyl)benzene to give the "dimeric" product 13a featuring a conjugated 14-membered core heterocyclic structure that contains a pair of FpXylB units.
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Affiliation(s)
- Karel Škoch
- Organisch-Chemisches Institut, Westfälische Wilhelms-Universität Münster, Corrensstraße 40, 48149, Münster, Germany.
| | - Constantin G Daniliuc
- Organisch-Chemisches Institut, Westfälische Wilhelms-Universität Münster, Corrensstraße 40, 48149, Münster, Germany.
| | - Gerald Kehr
- Organisch-Chemisches Institut, Westfälische Wilhelms-Universität Münster, Corrensstraße 40, 48149, Münster, Germany.
| | - Gerhard Erker
- Organisch-Chemisches Institut, Westfälische Wilhelms-Universität Münster, Corrensstraße 40, 48149, Münster, Germany.
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10
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Rauch F, Endres P, Friedrich A, Sieh D, Hähnel M, Krummenacher I, Braunschweig H, Finze M, Ji L, Marder TB. An Iterative Divergent Approach to Conjugated Starburst Borane Dendrimers. Chemistry 2020; 26:12951-12963. [PMID: 32428359 PMCID: PMC7590090 DOI: 10.1002/chem.202001985] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2020] [Revised: 05/13/2020] [Indexed: 12/21/2022]
Abstract
Using a new divergent approach, conjugated triarylborane dendrimers were synthesized up to the 2nd generation. The synthetic strategy consists of three steps: 1) functionalization, via iridium catalyzed C-H borylation; 2) activation, via fluorination of the generated boronate ester with K[HF2 ] or [N(nBu4 )][HF2 ]; and 3) expansion, via reaction of the trifluoroborate salts with aryl Grignard reagents. The concept was also shown to be viable for a convergent approach. All but one of the conjugated borane dendrimers exhibit multiple, distinct and reversible reduction potentials, making them potentially interesting materials for applications in molecular accumulators. Based on their photophysical properties, the 1st generation dendrimers exhibit good conjugation over the whole system. However, the conjugation does not increase further upon expansion to the 2nd generation, but the molar extinction coefficients increase linearly with the number of triarylborane subunits, suggesting a potential application as photonic antennas.
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Affiliation(s)
- Florian Rauch
- Institut für Anorganische Chemie and Institute for Sustainable Chemistry &Catalysis with Boron (ICB)Julius-Maximilians-Universität WürzburgAm Hubland97074WürzburgGermany
| | - Peter Endres
- Institut für Anorganische Chemie and Institute for Sustainable Chemistry &Catalysis with Boron (ICB)Julius-Maximilians-Universität WürzburgAm Hubland97074WürzburgGermany
| | - Alexandra Friedrich
- Institut für Anorganische Chemie and Institute for Sustainable Chemistry &Catalysis with Boron (ICB)Julius-Maximilians-Universität WürzburgAm Hubland97074WürzburgGermany
| | - Daniel Sieh
- Institut für Anorganische Chemie and Institute for Sustainable Chemistry &Catalysis with Boron (ICB)Julius-Maximilians-Universität WürzburgAm Hubland97074WürzburgGermany
| | - Martin Hähnel
- Institut für Anorganische Chemie and Institute for Sustainable Chemistry &Catalysis with Boron (ICB)Julius-Maximilians-Universität WürzburgAm Hubland97074WürzburgGermany
| | - Ivo Krummenacher
- Institut für Anorganische Chemie and Institute for Sustainable Chemistry &Catalysis with Boron (ICB)Julius-Maximilians-Universität WürzburgAm Hubland97074WürzburgGermany
| | - Holger Braunschweig
- Institut für Anorganische Chemie and Institute for Sustainable Chemistry &Catalysis with Boron (ICB)Julius-Maximilians-Universität WürzburgAm Hubland97074WürzburgGermany
| | - Maik Finze
- Institut für Anorganische Chemie and Institute for Sustainable Chemistry &Catalysis with Boron (ICB)Julius-Maximilians-Universität WürzburgAm Hubland97074WürzburgGermany
| | - Lei Ji
- Institut für Anorganische Chemie and Institute for Sustainable Chemistry &Catalysis with Boron (ICB)Julius-Maximilians-Universität WürzburgAm Hubland97074WürzburgGermany
- Frontiers Science Center for Flexible Electronics (FSCFE)Shaanxi Institute of Flexible Electronics (SIFE) &Shaanxi Institute of Biomedical Materials and Engineering (SIBME)Northwestern Polytechnical University127 West Youryi Road710072Xi'anChina
| | - Todd B. Marder
- Institut für Anorganische Chemie and Institute for Sustainable Chemistry &Catalysis with Boron (ICB)Julius-Maximilians-Universität WürzburgAm Hubland97074WürzburgGermany
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11
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Rauch F, Fuchs S, Friedrich A, Sieh D, Krummenacher I, Braunschweig H, Finze M, Marder TB. Highly Stable, Readily Reducible, Fluorescent, Trifluoromethylated 9-Borafluorenes. Chemistry 2020; 26:12794-12808. [PMID: 31999019 PMCID: PMC7589458 DOI: 10.1002/chem.201905559] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2019] [Indexed: 01/29/2023]
Abstract
Three different perfluoroalkylated borafluorenes (F Bf) were prepared and their electronic and photophysical properties were investigated. The systems have four trifluoromethyl moieties on the borafluorene moiety as well as two trifluoromethyl groups at the ortho positions of their exo-aryl moieties. They differ with regard to the para substituents on their exo-aryl moieties, being a proton (F XylF Bf, F Xyl: 2,6-bis(trifluoromethyl)phenyl), a trifluoromethyl group (F MesF Bf, F Mes: 2,4,6-tris(trifluoromethyl)phenyl) or a dimethylamino group (p-NMe2 -F XylF Bf, p-NMe2 -F Xyl: 4-(dimethylamino)-2,6-bis(trifluoromethyl)phenyl), respectively. All derivatives exhibit extraordinarily low reduction potentials, comparable to those of perylenediimides. The most electron-deficient derivative F MesF Bf was also chemically reduced and its radical anion isolated and characterized. Furthermore, all compounds exhibit very long fluorescent lifetimes of about 250 ns up to 1.6 μs; however, the underlying mechanisms responsible for this differ. The donor-substituted derivative p-NMe2 -F XylF Bf exhibits thermally activated delayed fluorescence (TADF) from a charge-transfer (CT) state, whereas the F MesF Bf and F XylF Bf borafluorenes exhibit only weakly allowed locally excited (LE) transitions due to their symmetry and low transition-dipole moments.
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Affiliation(s)
- Florian Rauch
- Institute for Inorganic Chemistry and Institute for Sustainable Chemistry & Catalysis with Boron (ICB)Julius-Maximilians-Universität WürzburgAm Hubland97074WürzburgGermany
| | - Sonja Fuchs
- Institute for Inorganic Chemistry and Institute for Sustainable Chemistry & Catalysis with Boron (ICB)Julius-Maximilians-Universität WürzburgAm Hubland97074WürzburgGermany
| | - Alexandra Friedrich
- Institute for Inorganic Chemistry and Institute for Sustainable Chemistry & Catalysis with Boron (ICB)Julius-Maximilians-Universität WürzburgAm Hubland97074WürzburgGermany
| | - Daniel Sieh
- Institute for Inorganic Chemistry and Institute for Sustainable Chemistry & Catalysis with Boron (ICB)Julius-Maximilians-Universität WürzburgAm Hubland97074WürzburgGermany
| | - Ivo Krummenacher
- Institute for Inorganic Chemistry and Institute for Sustainable Chemistry & Catalysis with Boron (ICB)Julius-Maximilians-Universität WürzburgAm Hubland97074WürzburgGermany
| | - Holger Braunschweig
- Institute for Inorganic Chemistry and Institute for Sustainable Chemistry & Catalysis with Boron (ICB)Julius-Maximilians-Universität WürzburgAm Hubland97074WürzburgGermany
| | - Maik Finze
- Institute for Inorganic Chemistry and Institute for Sustainable Chemistry & Catalysis with Boron (ICB)Julius-Maximilians-Universität WürzburgAm Hubland97074WürzburgGermany
| | - Todd B. Marder
- Institute for Inorganic Chemistry and Institute for Sustainable Chemistry & Catalysis with Boron (ICB)Julius-Maximilians-Universität WürzburgAm Hubland97074WürzburgGermany
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12
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Rauch F, Krebs J, Günther J, Friedrich A, Hähnel M, Krummenacher I, Braunschweig H, Finze M, Marder TB. Electronically Driven Regioselective Iridium-Catalyzed C-H Borylation of Donor-π-Acceptor Chromophores Containing Triarylboron Acceptors. Chemistry 2020; 26:10626-10633. [PMID: 32510684 PMCID: PMC7497074 DOI: 10.1002/chem.202002348] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2020] [Revised: 06/05/2020] [Indexed: 12/11/2022]
Abstract
We observed a surprisingly high electronically driven regioselectivity for the iridium-catalyzed C-H borylation of donor-π-acceptor (D-π-A) systems with diphenylamino (1) or carbazolyl (2) moieties as the donor, bis(2,6-bis(trifluoromethyl)phenyl)boryl (B(F Xyl)2 ) as the acceptor, and 1,4-phenylene as the π-bridge. Under our conditions, borylation was observed only at the sterically least encumbered para-positions of the acceptor group. As boronate esters are versatile building blocks for organic synthesis (C-C coupling, functional group transformations) the C-H borylation represents a simple potential method for post-functionalization by which electronic or other properties of D-π-A systems can be fine-tuned for specific applications. The photophysical and electrochemical properties of the borylated (1-(Bpin)2 ) and unborylated (1) diphenylamino-substituted D-π-A systems were investigated. Interestingly, the borylated derivative exhibits coordination of THF to the boronate ester moieties, influencing the photophysical properties and exemplifying the non-innocence of boronate esters.
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Affiliation(s)
- Florian Rauch
- Institut für Anorganische Chemie and Institute, for Sustainable Chemistry & Catalysis with Boron (ICB)Julius-Maximilians-Universität WürzburgAm Hubland97074WürzburgGermany
| | - Johannes Krebs
- Institut für Anorganische Chemie and Institute, for Sustainable Chemistry & Catalysis with Boron (ICB)Julius-Maximilians-Universität WürzburgAm Hubland97074WürzburgGermany
| | - Julian Günther
- Institut für Anorganische Chemie and Institute, for Sustainable Chemistry & Catalysis with Boron (ICB)Julius-Maximilians-Universität WürzburgAm Hubland97074WürzburgGermany
| | - Alexandra Friedrich
- Institut für Anorganische Chemie and Institute, for Sustainable Chemistry & Catalysis with Boron (ICB)Julius-Maximilians-Universität WürzburgAm Hubland97074WürzburgGermany
| | - Martin Hähnel
- Institut für Anorganische Chemie and Institute, for Sustainable Chemistry & Catalysis with Boron (ICB)Julius-Maximilians-Universität WürzburgAm Hubland97074WürzburgGermany
| | - Ivo Krummenacher
- Institut für Anorganische Chemie and Institute, for Sustainable Chemistry & Catalysis with Boron (ICB)Julius-Maximilians-Universität WürzburgAm Hubland97074WürzburgGermany
| | - Holger Braunschweig
- Institut für Anorganische Chemie and Institute, for Sustainable Chemistry & Catalysis with Boron (ICB)Julius-Maximilians-Universität WürzburgAm Hubland97074WürzburgGermany
| | - Maik Finze
- Institut für Anorganische Chemie and Institute, for Sustainable Chemistry & Catalysis with Boron (ICB)Julius-Maximilians-Universität WürzburgAm Hubland97074WürzburgGermany
| | - Todd B. Marder
- Institut für Anorganische Chemie and Institute, for Sustainable Chemistry & Catalysis with Boron (ICB)Julius-Maximilians-Universität WürzburgAm Hubland97074WürzburgGermany
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13
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Narsaria AK, Rauch F, Krebs J, Endres P, Friedrich A, Krummenacher I, Braunschweig H, Finze M, Nitsch J, Bickelhaupt FM, Marder TB. Computationally Guided Molecular Design to Minimize the LE/CT Gap in D-π-A Fluorinated Triarylboranes for Efficient TADF via D and π-Bridge Tuning. ADVANCED FUNCTIONAL MATERIALS 2020; 30:2002064. [PMID: 32774198 PMCID: PMC7405949 DOI: 10.1002/adfm.202002064] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/04/2020] [Revised: 03/29/2020] [Accepted: 04/03/2020] [Indexed: 05/16/2023]
Abstract
In this combined experimental and theoretical study, a computational protocol is reported to predict the excited states in D-π-A compounds containing the B(FXyl)2 (FXyl = 2,6-bis(trifluoromethyl)phenyl) acceptor group for the design of new thermally activated delayed fluorescence (TADF) emitters. To this end, the effect of different donor and π-bridge moieties on the energy gaps between local and charge-transfer singlet and triplet states is examined. To prove this computationally aided design concept, the D-π-B(FXyl)2 compounds 1-5 were synthesized and fully characterized. The photophysical properties of these compounds in various solvents, polymeric film, and in a frozen matrix were investigated in detail and show excellent agreement with the computationally obtained data. Furthermore, a simple structure-property relationship is presented on the basis of the molecular fragment orbitals of the donor and the π-bridge, which minimize the relevant singlet-triplet gaps to achieve efficient TADF emitters.
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Affiliation(s)
- Ayush K. Narsaria
- Department of Theoretical ChemistryAmsterdam Institute of Molecular and Life Sciences (AIMMS)and Amsterdam Center for Multiscale Modeling (ACMM)Vrije Universiteit AmsterdamDe Boelelaan 1083AmsterdamNL‐1081 HVThe Netherlands
| | - Florian Rauch
- Institute for Inorganic ChemistryJulius‐Maximilians‐Universität WürzburgAm HublandWürzburgD‐97074Germany
- Institute for Sustainable Chemistry & Catalysis with Boron Julius‐Maximilians‐Universität WürzburgAm HublandWürzburgD‐97074Germany
| | - Johannes Krebs
- Institute for Inorganic ChemistryJulius‐Maximilians‐Universität WürzburgAm HublandWürzburgD‐97074Germany
- Institute for Sustainable Chemistry & Catalysis with Boron Julius‐Maximilians‐Universität WürzburgAm HublandWürzburgD‐97074Germany
| | - Peter Endres
- Institute for Inorganic ChemistryJulius‐Maximilians‐Universität WürzburgAm HublandWürzburgD‐97074Germany
- Institute for Sustainable Chemistry & Catalysis with Boron Julius‐Maximilians‐Universität WürzburgAm HublandWürzburgD‐97074Germany
| | - Alexandra Friedrich
- Institute for Inorganic ChemistryJulius‐Maximilians‐Universität WürzburgAm HublandWürzburgD‐97074Germany
- Institute for Sustainable Chemistry & Catalysis with Boron Julius‐Maximilians‐Universität WürzburgAm HublandWürzburgD‐97074Germany
| | - Ivo Krummenacher
- Institute for Inorganic ChemistryJulius‐Maximilians‐Universität WürzburgAm HublandWürzburgD‐97074Germany
- Institute for Sustainable Chemistry & Catalysis with Boron Julius‐Maximilians‐Universität WürzburgAm HublandWürzburgD‐97074Germany
| | - Holger Braunschweig
- Institute for Inorganic ChemistryJulius‐Maximilians‐Universität WürzburgAm HublandWürzburgD‐97074Germany
- Institute for Sustainable Chemistry & Catalysis with Boron Julius‐Maximilians‐Universität WürzburgAm HublandWürzburgD‐97074Germany
| | - Maik Finze
- Institute for Inorganic ChemistryJulius‐Maximilians‐Universität WürzburgAm HublandWürzburgD‐97074Germany
- Institute for Sustainable Chemistry & Catalysis with Boron Julius‐Maximilians‐Universität WürzburgAm HublandWürzburgD‐97074Germany
| | - Jörn Nitsch
- Institute for Inorganic ChemistryJulius‐Maximilians‐Universität WürzburgAm HublandWürzburgD‐97074Germany
- Institute for Sustainable Chemistry & Catalysis with Boron Julius‐Maximilians‐Universität WürzburgAm HublandWürzburgD‐97074Germany
| | - F. Matthias Bickelhaupt
- Department of Theoretical ChemistryAmsterdam Institute of Molecular and Life Sciences (AIMMS)and Amsterdam Center for Multiscale Modeling (ACMM)Vrije Universiteit AmsterdamDe Boelelaan 1083AmsterdamNL‐1081 HVThe Netherlands
- Institute for Molecules and Materials (IMM)Radboud UniversityHeyendaalseweg 135NijmegenNL‐6525 AJThe Netherlands
| | - Todd B. Marder
- Institute for Inorganic ChemistryJulius‐Maximilians‐Universität WürzburgAm HublandWürzburgD‐97074Germany
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14
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Carden JL, Dasgupta A, Melen RL. Halogenated triarylboranes: synthesis, properties and applications in catalysis. Chem Soc Rev 2020; 49:1706-1725. [PMID: 32100762 DOI: 10.1039/c9cs00769e] [Citation(s) in RCA: 88] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Halogenated triarylboranes (BAr3) have been known for decades, however it has only been since the surge of interest in main group catalysis that their application as strong Lewis acid catalysts has been recognised. This review aims to look past the popular tris(pentafluorophenyl)borane [B(C6F5)3] to the other halogenated triarylboranes, to give a greater breadth of understanding as to how tuning the Lewis acidity of BAr3 by modifications of the aryl rings can lead to improved reactivity. In this review, a discussion on Lewis acidity determination of boranes is given, the synthesis of these boranes is discussed, and examples of how they are being used for catalysis and frustrated Lewis pair (FLP) chemistry are explained.
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Affiliation(s)
- Jamie L Carden
- Cardiff Catalysis Institute, School of Chemistry, Cardiff University, Main Building, Park Place, Cardiff, CF10 3AT, Cymru/Wales, UK.
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15
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Belaidi H, Rauch F, Zhang Z, Latouche C, Boucekkine A, Marder TB, Halet J. Insights into the Optical Properties of Triarylboranes with Strongly Electron‐Accepting Bis(fluoromesityl)boryl Groups: when Theory Meets Experiment. CHEMPHOTOCHEM 2019. [DOI: 10.1002/cptc.201900256] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Houmam Belaidi
- Univ Rennes, CNRSInstitut des Sciences Chimiques de Rennes UMR 6226 35000 Rennes France
| | - Florian Rauch
- Institut für Anorganische Chemie and Institute for Sustainable Chemistry & Catalysis with BoronJulius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Germany
| | - Zuolun Zhang
- Institut für Anorganische Chemie and Institute for Sustainable Chemistry & Catalysis with BoronJulius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Germany
- State Key Laboratory of Supramolecular Structure and Materials College of ChemistryJilin University Qianjin Street Changchun P. R. China
| | - Camille Latouche
- Institut des Matériaux Jean RouxelUniversité de Nantes, CNRS 2 rue de la Houssinière, BP 32229 44322 Nantes cedex 3 France
| | - Abdou Boucekkine
- Univ Rennes, CNRSInstitut des Sciences Chimiques de Rennes UMR 6226 35000 Rennes France
| | - Todd B. Marder
- Institut für Anorganische Chemie and Institute for Sustainable Chemistry & Catalysis with BoronJulius-Maximilians-Universität Würzburg Am Hubland 97074 Würzburg Germany
| | - Jean‐François Halet
- Univ Rennes, CNRSInstitut des Sciences Chimiques de Rennes UMR 6226 35000 Rennes France
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16
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Bennett EL, Lawrence EJ, Blagg RJ, Mullen AS, MacMillan F, Ehlers AW, Scott DJ, Sapsford JS, Ashley AE, Wildgoose GG, Slootweg JC. A New Mode of Chemical Reactivity for Metal-Free Hydrogen Activation by Lewis Acidic Boranes. Angew Chem Int Ed Engl 2019; 58:8362-8366. [PMID: 30968535 PMCID: PMC6594078 DOI: 10.1002/anie.201900861] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2019] [Revised: 04/09/2019] [Indexed: 12/13/2022]
Abstract
We herein explore whether tris(aryl)borane Lewis acids are capable of cleaving H2 outside of the usual Lewis acid/base chemistry described by the concept of frustrated Lewis pairs (FLPs). Instead of a Lewis base we use a chemical reductant to generate stable radical anions of two highly hindered boranes: tris(3,5-dinitromesityl)borane and tris(mesityl)borane. NMR spectroscopic characterization reveals that the corresponding borane radical anions activate (cleave) dihydrogen, whilst EPR spectroscopic characterization, supported by computational analysis, reveals the intermediates along the hydrogen activation pathway. This radical-based, redox pathway involves the homolytic cleavage of H2 , in contrast to conventional models of FLP chemistry, which invoke a heterolytic cleavage pathway. This represents a new mode of chemical reactivity for hydrogen activation by borane Lewis acids.
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Affiliation(s)
- Elliot L. Bennett
- School of ChemistryUniversity of East AngliaNorwich Research ParkNorwichNR4 7TJUK
| | - Elliot J. Lawrence
- School of ChemistryUniversity of East AngliaNorwich Research ParkNorwichNR4 7TJUK
| | - Robin J. Blagg
- School of ChemistryUniversity of East AngliaNorwich Research ParkNorwichNR4 7TJUK
| | - Anna S. Mullen
- School of ChemistryUniversity of East AngliaNorwich Research ParkNorwichNR4 7TJUK
| | - Fraser MacMillan
- School of ChemistryUniversity of East AngliaNorwich Research ParkNorwichNR4 7TJUK
| | - Andreas W. Ehlers
- Van 't Hoff Institute for Molecular SciencesUniversity of AmsterdamScience Park 904, PO Box 941571090 GDAmsterdamThe Netherlands
- Department of Chemistry, Science FacultyUniversity of JohannesburgPO Box 254, Auckland ParkJohannesburgSouth Africa
| | - Daniel J. Scott
- Molecular Sciences Research HubImperial College White City Campus80 Wood LaneLondonW12 0BZUK
| | - Joshua S. Sapsford
- Molecular Sciences Research HubImperial College White City Campus80 Wood LaneLondonW12 0BZUK
| | - Andrew E. Ashley
- Molecular Sciences Research HubImperial College White City Campus80 Wood LaneLondonW12 0BZUK
| | - Gregory G. Wildgoose
- School of ChemistryUniversity of East AngliaNorwich Research ParkNorwichNR4 7TJUK
| | - J. Chris Slootweg
- Van 't Hoff Institute for Molecular SciencesUniversity of AmsterdamScience Park 904, PO Box 941571090 GDAmsterdamThe Netherlands
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17
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Bennett EL, Lawrence EJ, Blagg RJ, Mullen AS, MacMillan F, Ehlers AW, Scott DJ, Sapsford JS, Ashley AE, Wildgoose GG, Slootweg JC. A New Mode of Chemical Reactivity for Metal‐Free Hydrogen Activation by Lewis Acidic Boranes. Angew Chem Int Ed Engl 2019. [DOI: 10.1002/ange.201900861] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Elliot L. Bennett
- School of ChemistryUniversity of East Anglia Norwich Research Park Norwich NR4 7TJ UK
| | - Elliot J. Lawrence
- School of ChemistryUniversity of East Anglia Norwich Research Park Norwich NR4 7TJ UK
| | - Robin J. Blagg
- School of ChemistryUniversity of East Anglia Norwich Research Park Norwich NR4 7TJ UK
| | - Anna S. Mullen
- School of ChemistryUniversity of East Anglia Norwich Research Park Norwich NR4 7TJ UK
| | - Fraser MacMillan
- School of ChemistryUniversity of East Anglia Norwich Research Park Norwich NR4 7TJ UK
| | - Andreas W. Ehlers
- Van 't Hoff Institute for Molecular SciencesUniversity of Amsterdam Science Park 904, PO Box 94157 1090 GD Amsterdam The Netherlands
- Department of Chemistry, Science FacultyUniversity of Johannesburg PO Box 254, Auckland Park Johannesburg South Africa
| | - Daniel J. Scott
- Molecular Sciences Research HubImperial College White City Campus 80 Wood Lane London W12 0BZ UK
| | - Joshua S. Sapsford
- Molecular Sciences Research HubImperial College White City Campus 80 Wood Lane London W12 0BZ UK
| | - Andrew E. Ashley
- Molecular Sciences Research HubImperial College White City Campus 80 Wood Lane London W12 0BZ UK
| | - Gregory G. Wildgoose
- School of ChemistryUniversity of East Anglia Norwich Research Park Norwich NR4 7TJ UK
| | - J. Chris Slootweg
- Van 't Hoff Institute for Molecular SciencesUniversity of Amsterdam Science Park 904, PO Box 94157 1090 GD Amsterdam The Netherlands
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18
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LaFortune JHW, Szkop KM, Farinha FE, Johnstone TC, Postle S, Stephan DW. Probing steric influences on electrophilic phosphonium cations: a comparison of [(3,5-(CF3)2C6H3)3PF]+ and [(C6F5)3PF]+. Dalton Trans 2018; 47:11411-11419. [DOI: 10.1039/c8dt02594k] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The electrophilic phosphonium cation (EPC) salt [(3,5-(CF3)2C6H3)3PF][B(C6F5)4] (2) can display catalytic activity greater than its thermodynamic acidity would suggest. The role of steric factors is explored.
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Affiliation(s)
| | - Kevin M. Szkop
- Department of Chemistry
- University of Toronto
- Toronto
- Canada M5S 3H6
| | - Farah E. Farinha
- Department of Chemistry
- University of Toronto
- Toronto
- Canada M5S 3H6
| | | | - Shawn Postle
- Department of Chemistry
- University of Toronto
- Toronto
- Canada M5S 3H6
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19
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Heshmat M, Privalov T. Computational Elucidation of a Role That Brønsted Acidification of the Lewis Acid-Bound Water Might Play in the Hydrogenation of Carbonyl Compounds with H 2 in Lewis Basic Solvents. Chemistry 2017; 23:11489-11493. [PMID: 28677868 DOI: 10.1002/chem.201700937] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2017] [Indexed: 11/08/2022]
Abstract
Brønsted acidification of water by Lewis acid (LA) complexation is one of the fundamental principles in chemistry. Using transition-state calculations (TS), herein we investigate the role that Brønsted acidification of the LA-bound water might play in the mechanism of the hydrogenation of carbonyl compounds in Lewis basic solvents under non-anhydrous conditions. The potential energy scans and TS calculations were carried out with a series of eight borane LAs as well as the commonly known strong LA AlCl3 in 1,4-dioxane or THF as Lewis basic solvents. Our molecular model consists of the dative LA-water adduct with hydrogen bonds to acetone and a solvent molecule plus one additional solvent molecule that participates is the TS structure describing the cleavage of H2 at acetone's carbonyl carbon atom. In all the molecular models applied here, acetone (O=CMe2 ) is the archetypical carbonyl substrate. We demonstrate that Brønsted acidification of the LA-bound water can indeed lower the barrier height of the solvent-involving H2 -cleavage at the acetone's carbonyl carbon atom. This is significant because at present it is believed that the mechanism of the herein considered reaction is described by the same mechanism regardless of whether the reaction conditions are strictly anhydrous or non-anhydrous. Our results offer an alternative to this belief that warrants consideration and further study.
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Affiliation(s)
- Mojgan Heshmat
- Department of Organic Chemistry, Stockholm University, Stockholm, 10691, Sweden
| | - Timofei Privalov
- Department of Organic Chemistry, Stockholm University, Stockholm, 10691, Sweden
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20
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21
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Körte LA, Schwabedissen J, Soffner M, Blomeyer S, Reuter CG, Vishnevskiy YV, Neumann B, Stammler HG, Mitzel NW. Tris(perfluorotolyl)borane-A Boron Lewis Superacid. Angew Chem Int Ed Engl 2017; 56:8578-8582. [DOI: 10.1002/anie.201704097] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2017] [Indexed: 01/23/2023]
Affiliation(s)
- Leif A. Körte
- Lehrstuhl für Anorganische Chemie und Strukturchemie and Centrum für Molekulare Materialien CM 2; Fakultät für Chemie; Universität Bielefeld; Universitätsstrasse 25 33615 Bielefeld Germany
| | - Jan Schwabedissen
- Lehrstuhl für Anorganische Chemie und Strukturchemie and Centrum für Molekulare Materialien CM 2; Fakultät für Chemie; Universität Bielefeld; Universitätsstrasse 25 33615 Bielefeld Germany
| | - Marcel Soffner
- Lehrstuhl für Anorganische Chemie und Strukturchemie and Centrum für Molekulare Materialien CM 2; Fakultät für Chemie; Universität Bielefeld; Universitätsstrasse 25 33615 Bielefeld Germany
| | - Sebastian Blomeyer
- Lehrstuhl für Anorganische Chemie und Strukturchemie and Centrum für Molekulare Materialien CM 2; Fakultät für Chemie; Universität Bielefeld; Universitätsstrasse 25 33615 Bielefeld Germany
| | - Christian G. Reuter
- Lehrstuhl für Anorganische Chemie und Strukturchemie and Centrum für Molekulare Materialien CM 2; Fakultät für Chemie; Universität Bielefeld; Universitätsstrasse 25 33615 Bielefeld Germany
| | - Yury V. Vishnevskiy
- Lehrstuhl für Anorganische Chemie und Strukturchemie and Centrum für Molekulare Materialien CM 2; Fakultät für Chemie; Universität Bielefeld; Universitätsstrasse 25 33615 Bielefeld Germany
| | | | - Hans-Georg Stammler
- Lehrstuhl für Anorganische Chemie und Strukturchemie and Centrum für Molekulare Materialien CM 2; Fakultät für Chemie; Universität Bielefeld; Universitätsstrasse 25 33615 Bielefeld Germany
| | - Norbert W. Mitzel
- Lehrstuhl für Anorganische Chemie und Strukturchemie and Centrum für Molekulare Materialien CM 2; Fakultät für Chemie; Universität Bielefeld; Universitätsstrasse 25 33615 Bielefeld Germany
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22
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Swarnakar AK, Ferguson MJ, McDonald R, Rivard E. Azido- and amido-substituted gallium hydrides supported by N-heterocyclic carbenes. Dalton Trans 2017; 46:1406-1412. [DOI: 10.1039/c6dt04595b] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The synthesis of azido- and amido-gallanes supported by hindered N-heterocyclic carbene donors is reported.
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Affiliation(s)
| | | | - Robert McDonald
- Department of Chemistry
- University of Alberta
- Edmonton
- Canada T6G 2G2
| | - Eric Rivard
- Department of Chemistry
- University of Alberta
- Edmonton
- Canada T6G 2G2
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23
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Elmer LM, Kehr G, Daniliuc CG, Siedow M, Eckert H, Tesch M, Studer A, Williams K, Warren TH, Erker G. The Chemistry of a Non-Interacting Vicinal Frustrated Phosphane/Borane Lewis Pair. Chemistry 2016; 23:6056-6068. [PMID: 27925311 DOI: 10.1002/chem.201603954] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2016] [Revised: 09/23/2016] [Indexed: 12/14/2022]
Abstract
The dimesitylphosphinocyclopentene/HB(C6 F5 )2 -derived vicinal trans-1,2-P/B frustrated Lewis pair (FLP) 4 shows no direct phosphane-borane interaction. Toward some reagents it behaves similar to an intermolecular FLP; it cleaves dihydrogen, deprotonates terminal alkynes, and adds to organic carbonyl compounds including CO2 . It shows typical intramolecular FLP reaction modes (cooperative 1,1-additions) to mesityl azide, to carbon monoxide, and to NO. The latter reaction yields a persistent P/B FLPNO nitroxide radical, which undergoes H-atom abstraction reactions. The FLP 4 serves as a template for the CO reduction by [HB(C6 F5 )2 ] to generate a FLP-η2 -formylborane. The formylborane moiety is removed from the FLP template by reaction with pyridine to yield a genuine pyridine stabilized formylborane that undergoes characteristic borane carbaldehyde reactions (Wittig olefination, imine formation). Most new products were characterized by X-ray diffraction.
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Affiliation(s)
- Lisa-Maria Elmer
- Organisch-Chemisches Institut, Universität Münster, Corrensstraße 40, 48149, Münster, Germany
| | - Gerald Kehr
- Organisch-Chemisches Institut, Universität Münster, Corrensstraße 40, 48149, Münster, Germany
| | - Constantin G Daniliuc
- Organisch-Chemisches Institut, Universität Münster, Corrensstraße 40, 48149, Münster, Germany
| | - Melanie Siedow
- Institut für Physikalische Chemie, Universutät Münster, Corrensstraße 28/30, 48149, Münster, Germany
| | - Hellmut Eckert
- Institut für Physikalische Chemie, Universutät Münster, Corrensstraße 28/30, 48149, Münster, Germany.,Instituto de Física Sao Carlos, Universidade de Sao Paulo, CP 369, 13560-970, Sao Carlos, SP, Brasil
| | - Matthias Tesch
- Organisch-Chemisches Institut, Universität Münster, Corrensstraße 40, 48149, Münster, Germany
| | - Armido Studer
- Organisch-Chemisches Institut, Universität Münster, Corrensstraße 40, 48149, Münster, Germany
| | - Kamille Williams
- Georgetown University, Department of Chemistry, Box 571227, Washington DC, 20057-1227, USA
| | - Timothy H Warren
- Georgetown University, Department of Chemistry, Box 571227, Washington DC, 20057-1227, USA
| | - Gerhard Erker
- Organisch-Chemisches Institut, Universität Münster, Corrensstraße 40, 48149, Münster, Germany
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24
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Blagg RJ, Simmons TR, Hatton GR, Courtney JM, Bennett EL, Lawrence EJ, Wildgoose GG. Novel B(Ar')2(Ar'') hetero-tri(aryl)boranes: a systematic study of Lewis acidity. Dalton Trans 2016; 45:6032-43. [PMID: 26541517 DOI: 10.1039/c5dt03854e] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
A series of homo- and hetero-tri(aryl)boranes incorporating pentafluorophenyl, 3,5-bis(trifluoromethyl)phenyl, and pentachlorophenyl groups, four of which are novel species, have been studied as the acidic component of frustrated Lewis pairs for the heterolytic cleavage of H2. Under mild conditions eight of these will cleave H2; the rate of cleavage depending on both the electrophilicity of the borane and the steric bulk around the boron atom. Electrochemical studies allow comparisons of the electrophilicity with spectroscopic measurements of Lewis acidity for different series of boranes. Discrepancies in the correlation between these two types of measurements, combined with structural characterisation of each borane, reveal that the twist of the aryl rings with respect to the boron-centred trigonal plane is significant from both a steric and electronic perspective, and is an important consideration in the design of tri(aryl)boranes as Lewis acids.
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Affiliation(s)
- Robin J Blagg
- School of Chemistry, University of East Anglia, Norwich, NR4 7TJ, UK.
| | - Trevor R Simmons
- School of Chemistry, University of East Anglia, Norwich, NR4 7TJ, UK.
| | - Georgina R Hatton
- School of Chemistry, University of East Anglia, Norwich, NR4 7TJ, UK.
| | - James M Courtney
- School of Chemistry, University of East Anglia, Norwich, NR4 7TJ, UK.
| | - Elliot L Bennett
- School of Chemistry, University of East Anglia, Norwich, NR4 7TJ, UK.
| | - Elliot J Lawrence
- School of Chemistry, University of East Anglia, Norwich, NR4 7TJ, UK.
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25
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Lawrence EJ, Clark ER, Curless LD, Courtney JM, Blagg RJ, Ingleson MJ, Wildgoose GG. Metal-free electrocatalytic hydrogen oxidation using frustrated Lewis pairs and carbon-based Lewis acids. Chem Sci 2016; 7:2537-2543. [PMID: 28660024 PMCID: PMC5477046 DOI: 10.1039/c5sc04564a] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2015] [Accepted: 01/06/2016] [Indexed: 02/04/2023] Open
Abstract
Whilst hydrogen is a potentially clean fuel for energy storage and utilisation technologies, its conversion to electricity comes at a high energetic cost. This demands the use of rare and expensive precious metal electrocatalysts. Electrochemical-frustrated Lewis pairs offer a metal-free, CO tolerant pathway to the electrocatalysis of hydrogen oxidation. They function by combining the hydrogen-activating ability of frustrated Lewis pairs (FLPs) with electrochemical oxidation of the resultant hydride. Here we present an electrochemical-FLP approach that utilises two different Lewis acids - a carbon-based N-methylacridinium cation that possesses excellent electrochemical attributes, and a borane that exhibits fast hydrogen cleavage kinetics and functions as a "hydride shuttle". This synergistic interaction provides a system that is electrocatalytic with respect to the carbon-based Lewis acid, decreases the required potential for hydrogen oxidation by 1 V, and can be recycled multiple times.
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Affiliation(s)
- Elliot J Lawrence
- Energy & Materials Laboratory , School of Chemistry , University of East Anglia , Norwich Research Park , Norwich , NR4 7TJ , UK .
| | - Ewan R Clark
- School of Chemistry , University of Manchester , Oxford Road , Manchester M13 9PL , UK .
| | - Liam D Curless
- School of Chemistry , University of Manchester , Oxford Road , Manchester M13 9PL , UK .
| | - James M Courtney
- Energy & Materials Laboratory , School of Chemistry , University of East Anglia , Norwich Research Park , Norwich , NR4 7TJ , UK .
| | - Robin J Blagg
- Energy & Materials Laboratory , School of Chemistry , University of East Anglia , Norwich Research Park , Norwich , NR4 7TJ , UK .
| | - Michael J Ingleson
- School of Chemistry , University of Manchester , Oxford Road , Manchester M13 9PL , UK .
| | - Gregory G Wildgoose
- Energy & Materials Laboratory , School of Chemistry , University of East Anglia , Norwich Research Park , Norwich , NR4 7TJ , UK .
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26
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Samigullin K, Soltani Y, Lerner HW, Wagner M, Bolte M. Conformational studies on heteroleptic trifluoromethyl-substituted phenylboranes. ACTA CRYSTALLOGRAPHICA SECTION C-STRUCTURAL CHEMISTRY 2016; 72:189-97. [PMID: 26942428 DOI: 10.1107/s2053229616002242] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/02/2016] [Accepted: 02/05/2016] [Indexed: 11/10/2022]
Abstract
Organoboranes carrying electron-withdrawing substituents are commonly used as Lewis acidic catalysts or cocatalysts in a variety of organic processes. These Lewis acids also became popular through their application in `frustrated Lewis pairs', i.e. combinations of Lewis acids and bases that are unable to fully neutralize each other due to steric or electronic effects. We have determined the crystal and molecular structures of four heteroleptic arylboranes carrying 2-(trifluoromethyl)phenyl, 2,6-bis(trifluoromethyl)phenyl, 3,5-bis(trifluoromethyl)phenyl or mesityl substituents. [3,5-Bis(trifluoromethyl)phenyl]bis[2-(trifluoromethyl)phenyl]borane, C22H11BF12, (I), crystallizes with two molecules in the asymmetric unit which show very similar geometric parameters. In one of the two molecules, both trifluoromethyl groups of the 3,5-bis(trifluoromethyl)phenyl substituent are disordered over two positions. In [3,5-bis(trifluoromethyl)phenyl]bis[2,6-bis(trifluoromethyl)phenyl]borane, C24H9BF18, (II), only one of the two meta-trifluoromethyl groups is disordered. In [2,6-bis(trifluoromethyl)phenyl]bis[3,5-bis(trifluoromethyl)phenyl]borane, C24H9BF18, (III), both meta-trifluoromethyl groups of only one 3,5-bis(trifluoromethyl)phenyl ring are disordered. [3,5-Bis(trifluoromethyl)phenyl]dimesitylborane, C26H25BF6, (IV), carries only one meta-trifluoromethyl-substituted phenyl ring, with one of the two trifluoromethyl groups disordered over two positions. In addition to compounds (I)-(IV), the structure of bis[2,6-bis(trifluoromethyl)phenyl]fluoroborane, C16H6BF13, (V), is presented. None of the ortho-trifluoromethyl groups is disordered in any of the five compounds. In all the structures, the boron centre is in a trigonal planar coordination. Nevertheless, the bond angles around this atom vary according to the bulkiness and mutual repulsion of the substituents of the phenyl rings. Also, the ortho-trifluoromethyl-substituted phenyl rings usually show longer B-C bonds and tend to be tilted out of the BC3 plane by a higher degree than the phenyl rings carrying ortho H atoms. A comparison with related structures corroborates the conclusions regarding the geometric parameters of the boron centre drawn from the five structures in this paper. On the other hand, CF3 groups in meta positions do not seem to have a marked effect on the geometry involving the boron centre. Furthermore, it has been observed for the structures reported here and those reported previously that for CF3 groups in ortho positions of the aromatic ring, disorder of the F atoms is less probable than for CF3 groups in meta or para positions of the ring.
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Affiliation(s)
- Kamil Samigullin
- Institut für Anorganische Chemie, J. W. Goethe-Universität Frankfurt, Max-von-Laue-Strasse 7, 60438 Frankfurt/Main, Germany
| | - Yashar Soltani
- Institut für Anorganische Chemie, J. W. Goethe-Universität Frankfurt, Max-von-Laue-Strasse 7, 60438 Frankfurt/Main, Germany
| | - Hans Wolfram Lerner
- Institut für Anorganische Chemie, J. W. Goethe-Universität Frankfurt, Max-von-Laue-Strasse 7, 60438 Frankfurt/Main, Germany
| | - Matthias Wagner
- Institut für Anorganische Chemie, J. W. Goethe-Universität Frankfurt, Max-von-Laue-Strasse 7, 60438 Frankfurt/Main, Germany
| | - Michael Bolte
- Institut für Anorganische Chemie, J. W. Goethe-Universität Frankfurt, Max-von-Laue-Strasse 7, 60438 Frankfurt/Main, Germany
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27
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Abstract
The first 1 : 1 : 1 hetero-tri(aryl)borane cleaves H2 with various Lewis bases, and its electrochemistry is studied.
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