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Zhang X, Yu J, Zhao C, Si Y. Elastic SiC Aerogel for Thermal Insulation: A Systematic Review. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2024:e2311464. [PMID: 38511588 DOI: 10.1002/smll.202311464] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/09/2023] [Revised: 02/19/2024] [Indexed: 03/22/2024]
Abstract
SiC aerogels with their lightweight nature and exceptional thermal insulation properties have emerged as the most ideal materials for thermal protection in hypersonic vehicles; However, conventional SiC aerogels are prone to brittleness and mechanical degradation when exposed to complex loads such as shock and mechanical vibration. Hence, preserving the structural integrity of aerogels under the combined influence of thermal and mechanical external forces is crucial not only for stabling their thermal insulation performance but also for determining their practicality in harsh environments. This review focuses on the optimization of design based on the structure-performance of SiC aerogels, providing a comprehensive review of the inherent correlations among structural stability, mechanical properties, and insulation performance. First, the thermal transfer mechanism of aerogels from a microstructural perspective is studied, followed by the relationship between the building blocks of SiC aerogels (0D particles, 1D nanowires/nanofibers) and their compression performance (including compressive resilience, compressive strength, and fatigue resistance). Moreover, the strategy to improve the high-temperature oxidation resistance and insulation performance of SiC aerogels is explored. Lastly, the challenges and future breakthrough directions for SiC aerogels are presented.
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Affiliation(s)
- Xuan Zhang
- State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of Materials Science and Engineering, Donghua University, Shanghai, 201620, China
| | - Jianyong Yu
- Innovation Center for Textile Science and Technology, Donghua University, Shanghai, 200051, China
| | - Cunyi Zhao
- Innovation Center for Textile Science and Technology, Donghua University, Shanghai, 200051, China
| | - Yang Si
- State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of Materials Science and Engineering, Donghua University, Shanghai, 201620, China
- Innovation Center for Textile Science and Technology, Donghua University, Shanghai, 200051, China
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2
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Zhang J, Wei R, Ren C, Liu LL, Wu L. Si-B Functional Group Exchange Reaction Enabled by a Catalytic Amount of BH 3: Scope, Mechanism, and Application. J Am Chem Soc 2023. [PMID: 37411027 DOI: 10.1021/jacs.3c05625] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/08/2023]
Abstract
Functional group exchanges based on single-bond transformation are rare and challenging. In this regard, functional group exchange reactions of hydrosilanes proved to be more problematic. This is because this exchange requires the cleavage of the C-Si bond, while the Si-H bond is relatively easily activated for hydrosilanes. Herein, we report the first Si-B functional group exchange reactions of hydrosilanes with hydroboranes simply enabled by BH3 as a catalyst. Our methodology works for various aryl and alkyl hydrosilanes and different hydroboranes with the tolerance of general functional groups (up to 115 examples). Control experiments and density functional theory (DFT) studies reveal a distinct reaction pathway that involves consecutive C-Si/B-H and C-B/B-H σ-bond metathesis. Further investigations of using more readily available chlorosilanes, siloxane, fluorosilane, and silylborane for Si-B functional group exchanges, Ge-B functional group exchanges, and depolymerizative Si-B exchanges of polysilanes are also demonstrated. Moreover, the regeneration of MeSiH3 from polymethylhydrosiloxane (PMHS) is achieved. Notably, the formal hydrosilylation of a wide range of alkenes with SiH4 and MeSiH3 to selectively produce (chiral)trihydrosilanes and (methyl)dihydrosilanes is realized using inexpensive and readily available PhSiH3 and PhSiH2Me as gaseous SiH4 and MeSiH3 surrogates.
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Affiliation(s)
- Jiong Zhang
- State Key Laboratory for Oxo Synthesis and Selective Oxidation, Lanzhou Institute of Chemical Physics (LICP), Chinese Academy of Sciences, Lanzhou 730000, P. R. China
- University of Chinese Academy of Sciences, Beijing 100049, P. R. China
| | - Rui Wei
- Department of Chemistry and Guangdong Provincial Key Laboratory of Catalysis, Southern University of Science and Technology, Shenzhen 518055, P. R. China
| | - Chunping Ren
- State Key Laboratory for Oxo Synthesis and Selective Oxidation, Lanzhou Institute of Chemical Physics (LICP), Chinese Academy of Sciences, Lanzhou 730000, P. R. China
| | - Liu Leo Liu
- Department of Chemistry and Guangdong Provincial Key Laboratory of Catalysis, Southern University of Science and Technology, Shenzhen 518055, P. R. China
| | - Lipeng Wu
- State Key Laboratory for Oxo Synthesis and Selective Oxidation, Lanzhou Institute of Chemical Physics (LICP), Chinese Academy of Sciences, Lanzhou 730000, P. R. China
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3
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Edlová T, Normand AT, Cattey H, Brandès S, Wu Y, Antonangelo A, Théron B, Bonnin Q, Carta M, Le Gendre P. Hydrosilylation and Silane Polymerization Catalyzed by Group 4 Amidometallocene Cations. Organometallics 2023. [DOI: 10.1021/acs.organomet.2c00642] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/06/2023]
Affiliation(s)
- Tereza Edlová
- Institut de Chimie Moléculaire de L’Université de Bourgogne (ICMUB), Université de Bourgogne, Dijon 21000, France
| | - Adrien T. Normand
- Institut de Chimie Moléculaire de L’Université de Bourgogne (ICMUB), Université de Bourgogne, Dijon 21000, France
| | - Hélène Cattey
- Institut de Chimie Moléculaire de L’Université de Bourgogne (ICMUB), Université de Bourgogne, Dijon 21000, France
| | - Stéphane Brandès
- Institut de Chimie Moléculaire de L’Université de Bourgogne (ICMUB), Université de Bourgogne, Dijon 21000, France
| | - Yue Wu
- Department of Chemistry, Faculty of Science and Engineering, Swansea University, Singleton Park, Swansea, Wales SA2 8PP, United Kingdom
| | - Ariana Antonangelo
- Department of Chemistry, Faculty of Science and Engineering, Swansea University, Singleton Park, Swansea, Wales SA2 8PP, United Kingdom
| | - Benjamin Théron
- Institut de Chimie Moléculaire de L’Université de Bourgogne (ICMUB), Université de Bourgogne, Dijon 21000, France
| | - Quentin Bonnin
- Institut de Chimie Moléculaire de L’Université de Bourgogne (ICMUB), Université de Bourgogne, Dijon 21000, France
| | - Mariolino Carta
- Department of Chemistry, Faculty of Science and Engineering, Swansea University, Singleton Park, Swansea, Wales SA2 8PP, United Kingdom
| | - Pierre Le Gendre
- Institut de Chimie Moléculaire de L’Université de Bourgogne (ICMUB), Université de Bourgogne, Dijon 21000, France
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4
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Fang F, Jiang Q, Klausen RS. Poly(cyclosilane) Connectivity Tunes Optical Absorbance. J Am Chem Soc 2022; 144:7834-7843. [PMID: 35467855 DOI: 10.1021/jacs.2c01820] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
We report herein the influence of skeletal connectivity on the conformation-dependent optical properties of cyclosilane homo- and copolymers. 1,3-Linked cyclosilanes were bathochromically shifted by 20 nm in solution relative to 1,4-linked cyclosilanes, an effect reproduced by quantum chemical calculations on oligomeric model systems. Polysilane optical properties are conformation-dependent, and 1,3-linked cyclosilanes were hypothesized to adopt a favorable conformation unavailable to 1,4-linked cyclosilanes constrained to an endocyclic gauche conformation. Copolymerization of the isomeric cyclosilanes 1,3Si6 and 1,4Si6 afforded linear statistical copolymers, as characterized by 1H and 29Si NMR spectroscopies. The distinct connectivity of each comonomer was found to give rise to tunable absorption spectra, where the position of the absorption band systematically increased with the increased corporation of 1,3Si6. Computational studies pointed to conformation-dependent changes in orbital symmetry in shifting the most intense transition from the low-energy highest occupied molecular orbital (HOMO) → lowest unoccupied molecular orbital (LUMO) transition to a higher-energy HOMO → LUMO + n transition. The results of these studies demonstrate for the first time the role of silicon skeletal connectivity in controlling conformation and optoelectronic properties and provide new insight into the structure-based design of solution-processable silicon-based polymeric materials.
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Affiliation(s)
- Fan Fang
- Department of Chemistry, Johns Hopkins University, 3400 N. Charles St, Baltimore, Maryland 21218, United States
| | - Qifeng Jiang
- Department of Chemistry, Johns Hopkins University, 3400 N. Charles St, Baltimore, Maryland 21218, United States
| | - Rebekka S Klausen
- Department of Chemistry, Johns Hopkins University, 3400 N. Charles St, Baltimore, Maryland 21218, United States
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5
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Yu B, Huang H. Recent Advances in C—X Bond Metathesis Reactions. CHINESE J ORG CHEM 2022. [DOI: 10.6023/cjoc202202003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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6
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Clarke JJ, Maekawa Y, Nambo M, Crudden CM. Borenium-Catalyzed Reduction of Pyridines through the Combined Action of Hydrogen and Hydrosilane. Org Lett 2021; 23:6617-6621. [PMID: 34383490 DOI: 10.1021/acs.orglett.1c01892] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Mesoionic carbene-stabilized borenium ions efficiently reduce substituted pyridines to piperidines in the presence of a hydrosilane and a hydrogen atmosphere. Control experiments and deuterium labeling studies demonstrate reversible hydrosilylation of the pyridine, enabling full reduction of the N-heterocycle under milder conditions. The silane is a critical reaction component to prevent adduct formation between the piperidine product and the borenium catalyst.
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Affiliation(s)
- Joshua J Clarke
- Department of Chemistry, Queen's University, 90 Bader Lane, Kingston, Ontario, Canada K7L 3N6
| | - Yuuki Maekawa
- Department of Chemistry, Queen's University, 90 Bader Lane, Kingston, Ontario, Canada K7L 3N6.,Institute of Transformative Bio-Molecules (WPI-ITbM), Nagoya University, Furo, Chikusa, Nagoya 464-8602, Japan
| | - Masakazu Nambo
- Institute of Transformative Bio-Molecules (WPI-ITbM), Nagoya University, Furo, Chikusa, Nagoya 464-8602, Japan
| | - Cathleen M Crudden
- Department of Chemistry, Queen's University, 90 Bader Lane, Kingston, Ontario, Canada K7L 3N6.,Institute of Transformative Bio-Molecules (WPI-ITbM), Nagoya University, Furo, Chikusa, Nagoya 464-8602, Japan
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7
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Klare HFT, Albers L, Süsse L, Keess S, Müller T, Oestreich M. Silylium Ions: From Elusive Reactive Intermediates to Potent Catalysts. Chem Rev 2021; 121:5889-5985. [PMID: 33861564 DOI: 10.1021/acs.chemrev.0c00855] [Citation(s) in RCA: 97] [Impact Index Per Article: 32.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The history of silyl cations has all the makings of a drama but with a happy ending. Being considered reactive intermediates impossible to isolate in the condensed phase for decades, their actual characterization in solution and later in solid state did only fuel the discussion about their existence and initially created a lot of controversy. This perception has completely changed today, and silyl cations and their donor-stabilized congeners are now widely accepted compounds with promising use in synthetic chemistry. This review provides a comprehensive summary of the fundamental facts and principles of the chemistry of silyl cations, including reliable ways of their preparation as well as their physical and chemical properties. The striking features of silyl cations are their enormous electrophilicity and as such reactivity as super Lewis acids as well as fluorophilicity. Known applications rely on silyl cations as reactants, stoichiometric reagents, and promoters where the reaction success is based on their steady regeneration over the course of the reaction. Silyl cations can even be discrete catalysts, thereby opening the next chapter of their way into the toolbox of synthetic methodology.
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Affiliation(s)
- Hendrik F T Klare
- Institut für Chemie, Technische Universität Berlin, Strasse des 17 Juni 115, 10623 Berlin, Germany
| | - Lena Albers
- Institut für Chemie, Carl von Ossietzky Universität Oldenburg, Carl von Ossietzky-Strasse 9-11, 26129 Oldenburg, Germany
| | - Lars Süsse
- Institut für Chemie, Technische Universität Berlin, Strasse des 17 Juni 115, 10623 Berlin, Germany
| | - Sebastian Keess
- Institut für Chemie, Technische Universität Berlin, Strasse des 17 Juni 115, 10623 Berlin, Germany
| | - Thomas Müller
- Institut für Chemie, Carl von Ossietzky Universität Oldenburg, Carl von Ossietzky-Strasse 9-11, 26129 Oldenburg, Germany
| | - Martin Oestreich
- Institut für Chemie, Technische Universität Berlin, Strasse des 17 Juni 115, 10623 Berlin, Germany
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8
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Merk A, Bührmann L, Kordts N, Görtemaker K, Schmidtmann M, Müller T. Intramolecular Halo Stabilization of Silyl Cations-Silylated Halonium- and Bis-Halo-Substituted Siliconium Borates. Chemistry 2021; 27:3496-3503. [PMID: 33184927 PMCID: PMC7898513 DOI: 10.1002/chem.202004838] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2020] [Indexed: 11/24/2022]
Abstract
The stabilizing neighboring effect of halo substituents on silyl cations was tested for a series of peri‐halo substituted acenaphthyl‐based silyl cations 3. The chloro‐ (3 b), bromo‐ (3 c), and iodo‐ (3 d) stabilized cations were synthesized by the Corey protocol. Structural and NMR spectroscopic investigations for cations 3 b–d supported by the results of density functional calculations, which indicate their halonium ion nature. According to the fluorobenzonitrile (FBN) method, the silyl Lewis acidity decreases along the series of halonium ions 3, the fluoronium ion 3 a being a very strong and the iodonium ion 3 d a moderate Lewis acid. Halonium ions 3 b and 3 c react with starting silanes in a substituent redistribution reaction and form siliconium ions 4 b and 4 c. The structure of siliconium borate 4 c2[B12Br12] reveals the trigonal bipyramidal coordination environment of the silicon atom with the two bromo substituents in the apical positions.
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Affiliation(s)
- Anastasia Merk
- Institute of Chemistry, Carl von Ossietzky University Oldenburg, Carl von Ossietzky-Str. 9-11, 26129, Oldenburg, Germany, European Union
| | - Lukas Bührmann
- Institute of Chemistry, Carl von Ossietzky University Oldenburg, Carl von Ossietzky-Str. 9-11, 26129, Oldenburg, Germany, European Union
| | - Natalie Kordts
- Institute of Chemistry, Carl von Ossietzky University Oldenburg, Carl von Ossietzky-Str. 9-11, 26129, Oldenburg, Germany, European Union
| | - Katharina Görtemaker
- Institute of Chemistry, Carl von Ossietzky University Oldenburg, Carl von Ossietzky-Str. 9-11, 26129, Oldenburg, Germany, European Union
| | - Marc Schmidtmann
- Institute of Chemistry, Carl von Ossietzky University Oldenburg, Carl von Ossietzky-Str. 9-11, 26129, Oldenburg, Germany, European Union
| | - Thomas Müller
- Institute of Chemistry, Carl von Ossietzky University Oldenburg, Carl von Ossietzky-Str. 9-11, 26129, Oldenburg, Germany, European Union
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9
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Guo C, Li M, Chen J, Luo Y. Highly selective redistribution of primary arylsilanes to secondary arylsilanes catalyzed by Ln(CH2C6H4NMe2-o)3@SBA-15. Chem Commun (Camb) 2020; 56:117-120. [DOI: 10.1039/c9cc07493g] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The organometallic–inorganic hybrid materials Ln(CH2C6H4NMe2-o)3@SBA-15 (Ln = La, Y) were prepared, which demonstrated extremely high selectivity (>99%) in catalyzing the redistribution of primary arylsilanes to secondary arylsilanes.
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Affiliation(s)
- Chenjun Guo
- School of Material Science and Chemical Engineering
- Ningbo University
- Ningbo 315211
- P. R. China
| | - Min Li
- School of Material Science and Chemical Engineering
- Ningbo University
- Ningbo 315211
- P. R. China
| | - Jue Chen
- School of Biological and Chemical Engineering
- Ningbo Institute of Technology
- Zhejiang University
- Ningbo 315100
- P. R. China
| | - Yunjie Luo
- School of Material Science and Chemical Engineering
- Ningbo University
- Ningbo 315211
- P. R. China
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10
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Liu Z, Shi X, Cheng J. Selective homo- and cross-desilacoupling of aryl and benzyl primary silanes catalyzed by a barium complex. Dalton Trans 2020; 49:8340-8346. [DOI: 10.1039/d0dt01158d] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
The selective catalytic desilacoupling of primary arylsilanes with primary benzylsilane or arylsilanes was achieved by barium complex [(TpAd,iPr)Ba(CH2C6H4NMe2-o)].
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Affiliation(s)
- Zhizhou Liu
- State Key Laboratory of Polymer Physics and Chemistry
- Changchun Institute of Applied Chemistry
- Chinese Academy of Sciences
- Changchun 130022
- China
| | - Xianghui Shi
- State Key Laboratory of Polymer Physics and Chemistry
- Changchun Institute of Applied Chemistry
- Chinese Academy of Sciences
- Changchun 130022
- China
| | - Jianhua Cheng
- State Key Laboratory of Polymer Physics and Chemistry
- Changchun Institute of Applied Chemistry
- Chinese Academy of Sciences
- Changchun 130022
- China
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11
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Rabanzo-Castillo KM, Hanif M, Söhnel T, Leitao EM. Synthesis, characterisation and electronic properties of naphthalene bridged disilanes. Dalton Trans 2019; 48:13971-13980. [PMID: 31483424 DOI: 10.1039/c9dt03058a] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Synthesis of naphthalene bridged disilanes 2R (R = Me, Ph) was performed via catalytic dehydrocoupling. Using RhCl(PPh3)3 as a catalyst, an intramolecular Si-Si bond was readily formed from the corresponding disilyl precursors 1R (R = Me, Ph). For catalytic reactions using (C6F5)3B(OH2), bridged siloxanes (3Ph and 3Me) were observed. Attempts to install the 1,8-naphthalene bridge directly onto a disilane resulted in an unusual product (4), containing two silicon centres bridged through one naphthyl group, and another naphthyl group attached to a single Si centre. In order for this product to form, both a Si to Si hydrogen shift rearrangement as well as Si-Si bond cleavage occurred. The effects of phenyl and methyl substitutions on the structure and electronic properties of the synthesised compounds was investigated by single crystal X-ray diffraction, as well as IR and multinuclear NMR spectroscopic analysis. In addition, theoretical UV-Vis absorption maxima were evaluated using density functional theory (TD-SCF) on a B3LYP/6-31(++)G** level of theory and compared with experimental UV-Vis spectroscopic data.
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Affiliation(s)
- Kristel M Rabanzo-Castillo
- School of Chemical Sciences, University of Auckland, Auckland, New Zealand. and The MacDiarmid Institute for Advanced Materials and Nanotechnology, New Zealand
| | - Muhammad Hanif
- School of Chemical Sciences, University of Auckland, Auckland, New Zealand.
| | - Tilo Söhnel
- School of Chemical Sciences, University of Auckland, Auckland, New Zealand. and The MacDiarmid Institute for Advanced Materials and Nanotechnology, New Zealand
| | - Erin M Leitao
- School of Chemical Sciences, University of Auckland, Auckland, New Zealand. and The MacDiarmid Institute for Advanced Materials and Nanotechnology, New Zealand
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12
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Hong M, Chen J, Chen EYX. Polymerization of Polar Monomers Mediated by Main-Group Lewis Acid-Base Pairs. Chem Rev 2018; 118:10551-10616. [PMID: 30350583 DOI: 10.1021/acs.chemrev.8b00352] [Citation(s) in RCA: 170] [Impact Index Per Article: 28.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The development of new or more sustainable, active, efficient, controlled, and selective polymerization reactions or processes continues to be crucial for the synthesis of important polymers or materials with specific structures or functions. In this context, the newly emerged polymerization technique enabled by main-group Lewis pairs (LPs), termed as Lewis pair polymerization (LPP), exploits the synergy and cooperativity between the Lewis acid (LA) and Lewis base (LB) sites of LPs, which can be employed as frustrated Lewis pairs (FLPs), interacting LPs (ILPs), or classical Lewis adducts (CLAs), to effect cooperative monomer activation as well as chain initiation, propagation, termination, and transfer events. Through balancing the Lewis acidity, Lewis basicity, and steric effects of LPs, LPP has shown several unique advantages or intriguing opportunities compared to other polymerization techniques and demonstrated its broad polar monomer scope, high activity, control or livingness, and complete chemo- or regioselectivity, as well as its unique application in materials chemistry. These advances made in LPP are comprehensively reviewed, with the scope of monomers focusing on heteroatom-containing polar monomers, while the polymerizations mediated by main-group LAs and LBs separately that are most relevant to the LPP are also highlighted or updated. Examples of applying the principles of the LPP and LP chemistry as a new platform for advancing materials chemistry are highlighted, and currently unmet challenges in the field of the LPP, and thus the suggested corresponding future research directions, are also presented.
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Affiliation(s)
- Miao Hong
- State Key Laboratory of Organometallic Chemistry , Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences , Shanghai 200032 , China
| | - Jiawei Chen
- Department of Chemistry , Columbia University , 3000 Broadway , New York , New York 10027 , United States
| | - Eugene Y-X Chen
- Department of Chemistry , Colorado State University , Fort Collins , Colorado 80523 , United States
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13
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Omann L, Pudasaini B, Irran E, Klare HFT, Baik MH, Oestreich M. Thermodynamic versus kinetic control in substituent redistribution reactions of silylium ions steered by the counteranion. Chem Sci 2018; 9:5600-5607. [PMID: 30061992 PMCID: PMC6048699 DOI: 10.1039/c8sc01833b] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2018] [Accepted: 05/20/2018] [Indexed: 02/02/2023] Open
Abstract
An in-depth experimental and theoretical study of the substituent exchange reaction of silylium ions is presented. Apart from the substitution pattern at the silicon atom, the selectivity of this process is predominantly influenced by the counteranion, which is introduced with the trityl salt in the silylium ion generation. In contrast to Müller's protocol for the synthesis of triarylsilylium ions under kinetic control, the use of Reed's carborane anions leads to contact ion pairs, allowing selective formation of trialkylsilylium ions under thermodynamic control. DFT calculations finally revealed an unexpected mechanism for the rate-determining alkyl exchange step, which is initiated by an unusual 1,2-silyl migration in the intermediate ipso-disilylated arenium ion. The resulting ortho-disilylated arenium ion can then undergo an alkyl transfer via a low-barrier five-centered transition state.
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Affiliation(s)
- Lukas Omann
- Institut für Chemie , Technische Universität Berlin , Strasse des 17. Juni 115 , 10623 Berlin , Germany .
| | - Bimal Pudasaini
- Center for Catalytic Hydrocarbon Functionalizations , Institute for Basic Science (IBS) , Daejeon , 34141 , Republic of Korea
| | - Elisabeth Irran
- Institut für Chemie , Technische Universität Berlin , Strasse des 17. Juni 115 , 10623 Berlin , Germany .
| | - Hendrik F T Klare
- Institut für Chemie , Technische Universität Berlin , Strasse des 17. Juni 115 , 10623 Berlin , Germany .
| | - Mu-Hyun Baik
- Center for Catalytic Hydrocarbon Functionalizations , Institute for Basic Science (IBS) , Daejeon , 34141 , Republic of Korea
- Department of Chemistry , Korea Advanced Institute of Science and Technology (KAIST) , Daejeon , 34141 , Republic of Korea .
| | - Martin Oestreich
- Institut für Chemie , Technische Universität Berlin , Strasse des 17. Juni 115 , 10623 Berlin , Germany .
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14
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Komiyama T, Minami Y, Furuya Y, Hiyama T. Palladium/Copper Dual Catalysis for the Cross‐Coupling of Aryl(trialkyl)silanes with Aryl Bromides. Angew Chem Int Ed Engl 2018. [DOI: 10.1002/ange.201712081] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Takeshi Komiyama
- Department of Applied Chemistry Chuo University 1-13-27, Kasuga Bunkyo-ku Tokyo 112-8551 Japan
| | - Yasunori Minami
- Research and Development Initiative Chuo University 1-13-27, Kasuga Bunkyo-ku Tokyo 112-8551 Japan
| | - Yuki Furuya
- Department of Applied Chemistry Chuo University 1-13-27, Kasuga Bunkyo-ku Tokyo 112-8551 Japan
| | - Tamejiro Hiyama
- Research and Development Initiative Chuo University 1-13-27, Kasuga Bunkyo-ku Tokyo 112-8551 Japan
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15
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Komiyama T, Minami Y, Furuya Y, Hiyama T. Palladium/Copper Dual Catalysis for the Cross‐Coupling of Aryl(trialkyl)silanes with Aryl Bromides. Angew Chem Int Ed Engl 2018; 57:1987-1990. [DOI: 10.1002/anie.201712081] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2017] [Indexed: 01/14/2023]
Affiliation(s)
- Takeshi Komiyama
- Department of Applied Chemistry Chuo University 1-13-27, Kasuga Bunkyo-ku Tokyo 112-8551 Japan
| | - Yasunori Minami
- Research and Development Initiative Chuo University 1-13-27, Kasuga Bunkyo-ku Tokyo 112-8551 Japan
| | - Yuki Furuya
- Department of Applied Chemistry Chuo University 1-13-27, Kasuga Bunkyo-ku Tokyo 112-8551 Japan
| | - Tamejiro Hiyama
- Research and Development Initiative Chuo University 1-13-27, Kasuga Bunkyo-ku Tokyo 112-8551 Japan
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16
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Ma Y, Zhang L, Luo Y, Nishiura M, Hou Z. B(C 6F 5) 3-Catalyzed C-Si/Si-H Cross-Metathesis of Hydrosilanes. J Am Chem Soc 2017; 139:12434-12437. [PMID: 28836780 DOI: 10.1021/jacs.7b08053] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The substituent redistribution of hydrosilanes on silicon through C-Si and Si-H bond cleavage and reformation is of great interest and importance, but this transformation is usually difficult to achieve in a selective fashion. By using electron-rich aromatic hydrosilanes, we have achieved for the first time the selective C-Si/Si-H bond homo- and cross-metathesis of a series of hydrosilanes in the presence of a boron catalyst B(C6F5)3. This protocol features simple reaction conditions, high chemoselectivity, wide substrate scope, and high functionality tolerance, offering a new pathway for the synthesis of multisubstituted functional silanes.
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Affiliation(s)
- Yuanhong Ma
- Organometallic Chemistry Laboratory, RIKEN , 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - Liang Zhang
- Organometallic Chemistry Laboratory, RIKEN , 2-1 Hirosawa, Wako, Saitama 351-0198, Japan.,Advanced Catalysis Research Group, RIKEN Center for Sustainable Resource Science , 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - Yong Luo
- Organometallic Chemistry Laboratory, RIKEN , 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - Masayoshi Nishiura
- Organometallic Chemistry Laboratory, RIKEN , 2-1 Hirosawa, Wako, Saitama 351-0198, Japan.,Advanced Catalysis Research Group, RIKEN Center for Sustainable Resource Science , 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
| | - Zhaomin Hou
- Organometallic Chemistry Laboratory, RIKEN , 2-1 Hirosawa, Wako, Saitama 351-0198, Japan.,Advanced Catalysis Research Group, RIKEN Center for Sustainable Resource Science , 2-1 Hirosawa, Wako, Saitama 351-0198, Japan
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17
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Omann L, Oestreich M. Catalytic Access to Indole-Fused Benzosiloles by 2-Fold Electrophilic C–H Silylation with Dihydrosilanes. Organometallics 2016. [DOI: 10.1021/acs.organomet.6b00801] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Lukas Omann
- Institut für Chemie, Technische Universität Berlin, Strasse des 17. Juni 115, 10623 Berlin, Germany
| | - Martin Oestreich
- Institut für Chemie, Technische Universität Berlin, Strasse des 17. Juni 115, 10623 Berlin, Germany
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18
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Elektrophile aromatische Substitution mit Siliciumelektrophilen: die katalytische Friedel‐Crafts‐C‐H‐Silylierung. Angew Chem Int Ed Engl 2016. [DOI: 10.1002/ange.201608470] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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19
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Bähr S, Oestreich M. Electrophilic Aromatic Substitution with Silicon Electrophiles: Catalytic Friedel-Crafts C-H Silylation. Angew Chem Int Ed Engl 2016; 56:52-59. [PMID: 27762042 DOI: 10.1002/anie.201608470] [Citation(s) in RCA: 116] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2016] [Indexed: 11/07/2022]
Abstract
Electrophilic aromatic substitution is a fundamental reaction in synthetic chemistry. It converts C-H bonds of sufficiently nucleophilic arenes into C-X and C-C bonds using either stoichiometrically added or catalytically generated electrophiles. These reactions proceed through Wheland complexes, cationic intermediates that rearomatize by proton release. Hence, these high-energy intermediates are nothing but protonated arenes and as such strong Brønsted acids. The formation of protons is an issue in those rare cases where the electrophilic aromatic substitution is reversible. This situation arises in the electrophilic silylation of C-H bonds as the energy of the intermediate Wheland complex is lowered by the β-silicon effect. As a consequence, protonation of the silylated arene is facile, and the reverse reaction usually occurs to afford the desilylated arene. Several new approaches to overcome this inherent challenge of C-H silylation by SE Ar were recently disclosed, and this Minireview summarizes this progress.
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Affiliation(s)
- Susanne Bähr
- Institut für Chemie, Technische Universität Berlin, Strasse des 17. Juni 115, 10623, Berlin, Germany
| | - Martin Oestreich
- Institut für Chemie, Technische Universität Berlin, Strasse des 17. Juni 115, 10623, Berlin, Germany
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20
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Abstract
A survey of the state-of-the-art in the development of synthetic methods to incorporate p-block elements into polymers is given. The incorporation of main group elements (groups 13-16) into long chains provides access to materials with fascinating chemical and physical properties imparted by the presence of inorganic groups. Perhaps the greatest impedance to the widespread academic and commercial use of p-block element-containing macromolecules is the synthetic challenge associated with linking inorganic elements into long chains. In recent years, creative methodologies have been developed to incorporate heteroatoms into polymeric structures, with perhaps the greatest advances occurring with hybrid organic-inorganic polymers composed of boron, silicon, phosphorus and sulfur. With these developments, materials are currently being realized that possess exciting chemical, photophysical and thermal properties that are not possible for conventional organic polymers. This review focuses on highlighting the most significant recent advances whilst giving an appropriate background for the general reader. Of particular focus will be advances made over the last two decades, with emphasis on the novel synthetic methodologies employed.
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Affiliation(s)
- Andrew M Priegert
- Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouer, British Columbia, CanadaV6T 1Z1.
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21
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Oestreich M, Hermeke J, Mohr J. A unified survey of Si-H and H-H bond activation catalysed by electron-deficient boranes. Chem Soc Rev 2015; 44:2202-20. [PMID: 25679769 DOI: 10.1039/c4cs00451e] [Citation(s) in RCA: 392] [Impact Index Per Article: 43.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
The bond activation chemistry of B(C6F5)3 and related electron-deficient boranes is currently experiencing a renaissance due to the fascinating development of frustrated Lewis pairs (FLPs). B(C6F5)3's ability to catalytically activate Si-H bonds through η(1) coordination opened the door to several unique reduction processes. The ground-breaking finding that the same family of fully or partially fluorinated boron Lewis acids allows for the related H-H bond activation, either alone or as a component of an FLP, brought considerable momentum into the area of transition-metal-free hydrogenation and, likewise, hydrosilylation. This review comprehensively summarises synthetic methods involving borane-catalysed Si-H and H-H bond activation. Systems corresponding to an FLP-type situation are not covered. Aside from the broad manifold of C=X bond reductions and C=X/C-X defunctionalisations, dehydrogenative (oxidative) Si-H couplings are also included.
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Affiliation(s)
- Martin Oestreich
- Institut für Chemie, Technische Universität Berlin, Straße des 17. Juni 115, D-10623 Berlin, Germany.
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22
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Chen J, Chen EYX. Elusive Silane-Alane Complex [SiH⋅⋅⋅Al]: Isolation, Characterization, and Multifaceted Frustrated Lewis Pair Type Catalysis. Angew Chem Int Ed Engl 2015. [DOI: 10.1002/ange.201502400] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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23
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Chen J, Chen EYX. Elusive Silane-Alane Complex [SiH⋅⋅⋅Al]: Isolation, Characterization, and Multifaceted Frustrated Lewis Pair Type Catalysis. Angew Chem Int Ed Engl 2015; 54:6842-6. [DOI: 10.1002/anie.201502400] [Citation(s) in RCA: 96] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2015] [Indexed: 11/10/2022]
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