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Rubinsztajn S, Chojnowski J, Mizerska U. Tris(pentafluorophenyl)borane-catalyzed Hydride Transfer Reactions in Polysiloxane Chemistry-Piers-Rubinsztajn Reaction and Related Processes. Molecules 2023; 28:5941. [PMID: 37630197 PMCID: PMC10459531 DOI: 10.3390/molecules28165941] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2023] [Revised: 07/28/2023] [Accepted: 08/02/2023] [Indexed: 08/27/2023] Open
Abstract
Tris(pentafluorophenyl)borane (TPFPB) is a unique Lewis acid that catalyzes the condensation between hydrosilanes (Si-H) and alkoxysilanes (Si-OR), leading to the formation of siloxane bonds (Si-OSi) with the release of hydrocarbon (R-H) as a byproduct-the so-called Piers-Rubinsztajn reaction. The analogous reactions of hydrosilanes with silanols (Si-OH), alcohols (R-OH), ethers (R-OR') or water in the presence of TPFPB leads to the formation of a siloxane bond, alkoxysilane (Si-OR or Si-OR') or silanol (Si-OH), respectively. The above processes, often referred to as Piers-Rubinsztajn reactions, provide new synthetic tools for the controlled synthesis of siloxane materials under mild conditions with high yields. The common feature of these reactions is the TPFPB-mediated hydride transfer from silicon to carbon or hydrogen. This review presents a summary of 20 years of research efforts related to this field, with a focus on new synthetic methodologies leading to numerous previously difficult to synthesize well-defined siloxane oligomers, polymers and copolymers of a complex structure and potential applications of these new materials. In addition, the mechanistic aspects of the recently discovered reactions involving hydride transfer from silicon to silicon are discussed in more detail.
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Affiliation(s)
- Slawomir Rubinsztajn
- Centre of Molecular and Macromolecular Studies of Polish Academy of Sciences, Sienkiewicza 112, 90-636 Lodz, Poland;
| | - Julian Chojnowski
- Centre of Molecular and Macromolecular Studies of Polish Academy of Sciences, Sienkiewicza 112, 90-636 Lodz, Poland;
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2
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Gao H, Battley A, Leitao EM. The ultimate Lewis acid catalyst: using tris(pentafluorophenyl) borane to create bespoke siloxane architectures. Chem Commun (Camb) 2022; 58:7451-7465. [PMID: 35726789 DOI: 10.1039/d2cc00441k] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The breadth of utility of a commercially available and stable strong Lewis acid catalyst, tris(pentafluorophenyl)borane, has been explored, highlighting its use towards a wide range of unique siloxane products and their corresponding applications. This article focuses on the variety of different outcomes that this impressive borane offers in controlled and selective manners by the variation of reaction conditions, precursor functionalities, reagent or catalyst loading, and the mechanistic considerations that contribute. With a predominant focus on the Piers-Rubinsztajn reaction and its modifications, tris(pentaflurophenyl)borane's utility is highlighted in the synthesis of linear, cyclic and macrocyclic siloxanes, aryl-/alkoxysiloxanes, and other bespoke products. The significance of the catalytic transformation within the field of siloxane chemistry is discussed alongside some of the challenges that arise from using the borane catalyst.
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Affiliation(s)
- Hetian Gao
- School of Chemical Sciences, University of Auckland, Private Bag, 92019, Auckland, 1142, New Zealand. .,The MacDiarmid Institute for Advanced Materials and Nanotechnology, New Zealand
| | - Andrew Battley
- School of Chemical Sciences, University of Auckland, Private Bag, 92019, Auckland, 1142, New Zealand.
| | - Erin M Leitao
- School of Chemical Sciences, University of Auckland, Private Bag, 92019, Auckland, 1142, New Zealand. .,The MacDiarmid Institute for Advanced Materials and Nanotechnology, New Zealand
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3
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Rodríguez-Izquierdo I, Sepúlveda-Crespo D, Lasso JM, Resino S, Muñoz-Fernández MÁ. Baseline and time-updated factors in preclinical development of anionic dendrimers as successful anti-HIV-1 vaginal microbicides. WILEY INTERDISCIPLINARY REVIEWS. NANOMEDICINE AND NANOBIOTECHNOLOGY 2022; 14:e1774. [PMID: 35018739 PMCID: PMC9285063 DOI: 10.1002/wnan.1774] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/18/2021] [Revised: 12/05/2021] [Accepted: 12/09/2021] [Indexed: 12/12/2022]
Abstract
Although a wide variety of topical microbicides provide promising in vitro and in vivo efficacy, most of them failed to prevent sexual transmission of human immunodeficiency virus type 1 (HIV‐1) in human clinical trials. In vitro, ex vivo, and in vivo models must be optimized, considering the knowledge acquired from unsuccessful and successful clinical trials to improve the current gaps and the preclinical development protocols. To date, dendrimers are the only nanotool that has advanced to human clinical trials as topical microbicides to prevent HIV‐1 transmission. This fact demonstrates the importance and the potential of these molecules as microbicides. Polyanionic dendrimers are highly branched nanocompounds with potent activity against HIV‐1 that disturb HIV‐1 entry. Herein, the most significant advancements in topical microbicide development, trying to mimic the real‐life conditions as closely as possible, are discussed. This review also provides the preclinical assays that anionic dendrimers have passed as microbicides because they can improve current antiviral treatments' efficacy. This article is categorized under:Nanotechnology Approaches to Biology > Nanoscale Systems in Biology Therapeutic Approaches and Drug Discovery > Nanomedicine for Infectious Disease Toxicology and Regulatory Issues in Nanomedicine > Regulatory and Policy Issues in Nanomedicine
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Affiliation(s)
| | - Daniel Sepúlveda-Crespo
- Unidad de Infección Viral e Inmunidad, Centro Nacional de Microbiología, Instituto de Salud Carlos III, Madrid, Spain
| | | | - Salvador Resino
- Unidad de Infección Viral e Inmunidad, Centro Nacional de Microbiología, Instituto de Salud Carlos III, Madrid, Spain
| | - Ma Ángeles Muñoz-Fernández
- Instituto de Investigación Sanitaria Gregorio Marañón (IiSGM), Madrid, Spain.,Spanish HIV HGM BioBank, Madrid, Spain.,Section of Immunology, Laboratorio InmunoBiología Molecular, Hospital General Universitario Gregorio Marañón (HGUGM), Madrid, Spain
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4
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Kowalczyk S, Dębowski M, Iuliano A, Brzeski S, Plichta A. Synthesis of (Hyper)Branched Monohydroxyl Alkoxysilane Oligomers toward Silanized Urethane Prepolymers. Molecules 2022; 27:molecules27092790. [PMID: 35566135 PMCID: PMC9105832 DOI: 10.3390/molecules27092790] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2022] [Revised: 04/20/2022] [Accepted: 04/25/2022] [Indexed: 12/10/2022] Open
Abstract
The aim of this work was the synthesis of (hyper)branched oligomers based on trialkoxysilane in various conditions and further application of them in order to modify the urethane prepolymers. Hydroxyl-terminated trialkoxysilane was used as a monomer for homo-condensation. It was obtained by reaction of 3-aminopropyl trialkoxysilane (APTES) with ethylene carbonate (EC). The reaction was based on the attack of amine at the carbonyl carbon atom followed by ring opening of the carbonate to give a urethane (carbamate) product. The next step was the condensation via substitution of ethoxy groups on silicon atom with the terminal hydroxyalkyl groups present in the primary product with the evolution of ethanol. Accordingly, the impact of temperature and type of catalyst on process efficiency was investigated. A quantitative analysis of reaction progress and products of the conversion of EC together with ethanol evolution was conducted by means of gas chromatography, which allowed us to determine the formation of monomeric product and, indirectly, of oligomeric products. It was found that at room temperature after 24 h, the majority of the monomeric product was isolated, whereas at elevated temperature in the presence of Ti-based catalyst, further condensation of the monomer into branched oligomers was preferred, and, moreover, the application of vacuum intensified that process. The obtained products were structurally characterized by 1H and 29Si NMR, MALDI-ToF and Gel Permeation Chromatography. Finally, two different alkoxysilane products, monomeric and oligomeric, were applied for modification of urethane prepolymer, forming silanized one (SPUR). The influence of the silanizing agent on the mechanical and thermal properties of the moisture-cured products was shown before and after additional conditioning in water.
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Melendez-Zamudio M, Chavda K, Brook MA. Chelating Silicone Dendrons: Trying to Impact Organisms by Disrupting Ions at Interfaces. MOLECULES (BASEL, SWITZERLAND) 2022; 27:molecules27061869. [PMID: 35335233 PMCID: PMC8954278 DOI: 10.3390/molecules27061869] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/25/2022] [Revised: 03/09/2022] [Accepted: 03/10/2022] [Indexed: 12/02/2022]
Abstract
The viability of pathogens at interfaces can be disrupted by the presence of (cationic) charge and chelating groups. We report on the synthesis of silicone dendrimers and linear polymers based on a motif of hexadentate ligands with the ability to capture and deliver metal ions. Mono-, di- or trialkoxysilanes are converted in G1 to analogous vinylsilicones and then, iteratively using the Piers-Rubinsztajn reaction and hydrosilylation, each vinyl group is transformed into a trivinyl cluster at G2. The thiol-ene reaction with cysteamine or 3-mercaptopropionic acid and the trivinyl cluster leads to hexadentate ligands 3 × N–S or 3 × HOOC–S. The compounds were shown to effectively capture a variety of metals ions. Copper ion chelation was pursued in more detail, because of its toxicity. On average, metal ions form chelates with 2.4 of the three ligands in a cluster. Upon chelation, viscous oils are converted to (very) soft elastomers. Most of the ions could be stripped from the elastomers using aqueous EDTA solutions, demonstrating the ability of the silicones to both sequester and deliver ions. However, complete ion removal is not observed; at equilibrium, the silicones remain ionically crosslinked.
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Szawiola A, Lessard BH, Raboui H, Bender TP. Use of Piers-Rubinsztajn Chemistry to Access Unique and Challenging Silicon Phthalocyanines. ACS OMEGA 2021; 6:26857-26869. [PMID: 34693107 PMCID: PMC8529611 DOI: 10.1021/acsomega.1c02738] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/25/2021] [Accepted: 09/15/2021] [Indexed: 05/22/2023]
Abstract
Axial functionalization is one mode that enables the solubility of silicon phthalocyanines (SiPcs). Our group observed that the use of typical axial functionalization methodologies on reaction of Cl2SiPc with the chlorotriphenyl silane reagent unexpectedly resulted in the equal formation of triphenyl silyloxy silicon tetrabenzotriazacorrole ((3PS)-SiTbc) and the desired bis(tri-phenyl siloxy)-silicon phthalocyanine ((3PS)2-SiPc). The formation of a (3PS)-SiTbc was unexpected, and the separation of (3PS)-SiTbc and (3PS)2-SiPc was difficult. Therefore, in this study, we investigated the use of Piers-Rubinsztajn (PR) chemistry as an alternative method to functionalize the axial position of a SiPc to avoid the generation of a Tbc derivative. PR chemistry is a novel method to form a Si-O bond starting with a Si-H-based reactant and a -OH-based nucleophile enabled by tris(pentafluorophenyl)borane as a catalyst. The PR chemistry was screened on several fronts on how it can be applied to SiPcs. It was found that the process needs to be run in nitrobenzene at a molar ratio and at a particular temperature. To this end, the triphenylsiloxy derivative (3PS)2-SiPc was produced and fully characterized, without the production of a Tbc derivative. In addition, we explored and outlined that the PR chemistry method can enable the formation of other SiPc derivatives that are inaccessible utilizing other established axial substitution chemistry methods such as (TM3)2-SiPc and (MDM)2-SiPc. These additional materials were also physically characterized. The main conclusion is that the PR chemistry method can be applied to SiPcs and yield several alternative derivatives and has the potential to apply to additional macrocyclic compounds for unique derivative formation.
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Affiliation(s)
- Anjuli
M. Szawiola
- Department
of Chemistry, University of Toronto, 80 St. George Street, Toronto, Ontario M5S 3H6, Canada
| | - Benoit H. Lessard
- Department
of Chemical & Biological Engineering, University of Ottawa, 161 Louis Pasteur, Ottawa, Ontario K1N 6N5, Canada
| | - Hasan Raboui
- Department
of Chemical Engineering and Applied Chemistry, University of Toronto, 200 College Street, Toronto, Ontario M5S 3E5, Canada
| | - Timothy P. Bender
- Department
of Chemistry, University of Toronto, 80 St. George Street, Toronto, Ontario M5S 3H6, Canada
- Department
of Chemical Engineering and Applied Chemistry, University of Toronto, 200 College Street, Toronto, Ontario M5S 3E5, Canada
- Department
of Materials Science and Engineering, University
of Toronto, 184 College
Street, Toronto, Ontario M5S 3E4, Canada
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Lusterio A, Melendez-Zamudio M, Brook MA. Aminosilicones without Protecting Groups: Using Natural Amines. Ind Eng Chem Res 2021. [DOI: 10.1021/acs.iecr.1c00201] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Affiliation(s)
- Adrien Lusterio
- Department of Chemistry and Chemical Biology, McMaster University, 1280 Main St. W., Hamilton, ON, Canada L8S 4M1
| | - Miguel Melendez-Zamudio
- Department of Chemistry and Chemical Biology, McMaster University, 1280 Main St. W., Hamilton, ON, Canada L8S 4M1
| | - Michael A. Brook
- Department of Chemistry and Chemical Biology, McMaster University, 1280 Main St. W., Hamilton, ON, Canada L8S 4M1
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Liao M, Chen Y, Brook MA. Spatially Controlled Highly Branched Vinylsilicones. Polymers (Basel) 2021; 13:polym13060859. [PMID: 33799627 PMCID: PMC8000532 DOI: 10.3390/polym13060859] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2021] [Revised: 03/06/2021] [Accepted: 03/09/2021] [Indexed: 01/18/2023] Open
Abstract
Branched silicones possess interesting properties as oils, including their viscoelastic behavior, or as precursors to controlled networks. However, highly branched silicone polymers are difficult to form reliably using a “grafting to” strategy because functional groups may be bunched together preventing complete conversion for steric reasons. We report the synthesis of vinyl-functional highly branched silicone polymers based, at their core, on the ability to spatially locate functional vinyl groups along a silicone backbone at the desired frequency. Macromonomers were created and then polymerized using the Piers–Rubinsztajn reaction with dialkoxyvinylsilanes and telechelic HSi-silicones; molecular weights of the polymerized macromonomers were controlled by the ratio of the two reagents. The vinyl groups were subjected to iterative (two steps, one pot) hydrosilylation with alkoxysilane and Piers–Rubinsztajn reactions, leading to high molecular weight, highly branched silicones after one or two iterations. The vinyl-functional products can optionally be converted to phenyl/methyl-modified branched oils or elastomers.
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Kawatsu T, Fuchise K, Takeuchi K, Choi JC, Sato K, Matsumoto K. Well-defined hydrogen and organofunctional polysiloxanes with spiro-fused siloxane backbones. Polym Chem 2021. [DOI: 10.1039/d0py01503b] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Structurally well-defined macrocyclic polysiloxanes with unique spirosiloxane units and regularly arranged Si–H groups were synthesized by B(C6F5)3-catalyzed dehydrocarbonative cross-couplings.
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Affiliation(s)
- Takahiro Kawatsu
- Interdisciplinary Research Center for Catalytic Chemistry (IRC3)
- National Institute of Advanced Industrial Science and Technology (AIST)
- Tsukuba
- Japan
| | - Keita Fuchise
- Interdisciplinary Research Center for Catalytic Chemistry (IRC3)
- National Institute of Advanced Industrial Science and Technology (AIST)
- Tsukuba
- Japan
| | - Katsuhiko Takeuchi
- Interdisciplinary Research Center for Catalytic Chemistry (IRC3)
- National Institute of Advanced Industrial Science and Technology (AIST)
- Tsukuba
- Japan
| | - Jun-Chul Choi
- Interdisciplinary Research Center for Catalytic Chemistry (IRC3)
- National Institute of Advanced Industrial Science and Technology (AIST)
- Tsukuba
- Japan
| | - Kazuhiko Sato
- Interdisciplinary Research Center for Catalytic Chemistry (IRC3)
- National Institute of Advanced Industrial Science and Technology (AIST)
- Tsukuba
- Japan
| | - Kazuhiro Matsumoto
- Interdisciplinary Research Center for Catalytic Chemistry (IRC3)
- National Institute of Advanced Industrial Science and Technology (AIST)
- Tsukuba
- Japan
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10
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Hyperbranched Polycarbosiloxanes: Synthesis by Piers-Rubinsztajn Reaction and Application as Precursors to Magnetoceramics. Polymers (Basel) 2020; 12:polym12030672. [PMID: 32192198 PMCID: PMC7183318 DOI: 10.3390/polym12030672] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2020] [Revised: 03/14/2020] [Accepted: 03/16/2020] [Indexed: 01/10/2023] Open
Abstract
Silicon-containing hyperbranched polymers (Si-HBPs) have drawn much attention due to their promising applications. However, the construction of Si-HBPs, especially those containing functional aromatic units in the branched backbones by the simple and efficient Piers-Rubinsztajn (P–R) reaction, has been rarely developed. Herein, a series of novel hyperbranched polycarbosiloxanes were prepared by the P–R reactions of methyl-, or phenyl-triethoxylsilane and three Si–H containing aromatic monomers, including 1,4-bis(dimethylsilyl)benzene, 4,4′-bis(dimethylsilyl)-1,1′-biphenyl and 1,1′-bis(dimethylsilyl)ferrocene, using B(C6F5)3 as the catalyst for 0.5 h at room temperature. Their structures were fully characterized by Fourier transform infrared spectroscopy, 1H NMR, 13C NMR, and 29Si NMR. The molecular weights were determined by gel permeation chromatography. The degrees of branching of these polymers were 0.69–0.89, which were calculated based on the quantitative 29Si NMR spectroscopy. For applications, the ferrocene-linked Si-HBP can be used as precursors to produce functional ceramics with good magnetizability after pyrolysis at elevated temperature.
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11
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Sandoval-Yañez C, Castro Rodriguez C. Dendrimers: Amazing Platforms for Bioactive Molecule Delivery Systems. MATERIALS (BASEL, SWITZERLAND) 2020; 13:E570. [PMID: 31991703 PMCID: PMC7040653 DOI: 10.3390/ma13030570] [Citation(s) in RCA: 63] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Revised: 01/13/2020] [Accepted: 01/15/2020] [Indexed: 02/06/2023]
Abstract
Today, dendrimers are the main nanoparticle applied to drug delivery systems. The physicochemical characteristics of dendrimers and their versatility structural modification make them attractive to applied as a platform to bioactive molecules transport. Nanoformulations based on dendrimers enhance low solubility drugs, arrival to the target tissue, drugs bioavailability, and controlled release. This review describes the latter approaches on the transport of bioactive molecules based on dendrimers. The review focus is on the last therapeutic strategies addressed by dendrimers conjugated with bioactive molecules. A brief review of the latest studies in therapies against cancer and cardiovascular diseases, as well as future projections in the area, are addressed.
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Affiliation(s)
- Claudia Sandoval-Yañez
- Institute of Applied Chemical Sciences, Faculty of Engineering, Universidad Autonoma de Chile, El Llano Subercaseaux 2801, San Miguel 8910060, Santiago-Chile, Chile
| | - Cristian Castro Rodriguez
- Departamento de Química, Facultad de Ciencias, Universidad de Tarapacá, Avenida General Velásquez 1775, Arica-Chile 1000007, Chile;
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12
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Zheng S, Liang S, Chen Y, Brook MA. Hyperbranched Silicone MDTQ Tack Promoters. Molecules 2019; 24:molecules24224133. [PMID: 31731621 PMCID: PMC6891585 DOI: 10.3390/molecules24224133] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2019] [Revised: 11/11/2019] [Accepted: 11/11/2019] [Indexed: 01/31/2023] Open
Abstract
Low molecular weight, highly crosslinked silicone resins are widely used as reinforcing agents for highly transparent elastomers and adhesion/tack promoters in gels. The resins are complex mixtures and their structure / property relationships are ill defined. We report the synthesis of a library of 2, 3 and 4-fold hyperbranched polymeric oils that are comprised of linear, lightly branched or highly branched dendronic structures. Rheological examination of the fluids and tack measurements of gels filled with 10, 25 or 50% dendronic oils were made. Viscosity of the hyperbranched oils themselves was related to molecular weight, but more significantly to branch density. The properties are driven by chain entanglement. When cured into a silicone gel, less densely branched materials were more effective in improving tack than either linear oils or Me3SiO-rich, very highly branched oils of comparable molecular weight, because the latter oils underwent phase separation.
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Peng J, Bai Y, Li J. Piers-Rubinsztajn Reaction and the Application in Siloxane/Polysiloxane Chemistry. LETT ORG CHEM 2019. [DOI: 10.2174/1570178615666181016114942] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
By using the Piers-Rubinsztajn processes, elastomers, foams, silicone surfactants and copolymers with alkoxy-functional arylamines and ethers can be prepared. The preparation and applications of siloxane-based materials through Piers-Rubinsztajn reaction synthesis pathway have been reviewed.
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Affiliation(s)
- Jiajian Peng
- Key Laboratory of Organosilicon Chemistry and Material Technology of Ministry of Education, Hangzhou Normal University, Hangzhou 311121, China
| | - Ying Bai
- Key Laboratory of Organosilicon Chemistry and Material Technology of Ministry of Education, Hangzhou Normal University, Hangzhou 311121, China
| | - Jiayun Li
- Key Laboratory of Organosilicon Chemistry and Material Technology of Ministry of Education, Hangzhou Normal University, Hangzhou 311121, China
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Kamino BA, Szawiola AM, Plint T, Bender TP. Formation and application of electrochemically active cross-linked triarylamine–siloxane films using the Piers–Rubinsztajn reaction. CAN J CHEM 2019. [DOI: 10.1139/cjc-2018-0071] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Cross-linked triarylamine–siloxane hybrid thin film have been formed using Piers–Rubinsztajn chemistry. Key to this approach was the use of a ring-opening reaction to prevent the evolution of volatile small molecules. A representative cyclic ether containing biphenyl triarylamine compound was synthesized and on ring-opening was shown to form a smooth, glassy, and electroactive films by cross-linking with tetrakis(dimethylsiloxy)silane (QM*4). It was found that the films were electrochemically active with low glass transition temperatures. Cross-linked films were incorporated into organic light emitting diodes (OLEDs) under various conditions and functionality within OLEDs was confirmed. Finally, the resistance of the system to dissolution (orthogonality) was considered by casting F8T2, a p-type emitting polymer, from solution on top of the cross-linked film, which formed a working OLED.
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Affiliation(s)
- Brett A. Kamino
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, 200 College St., Toronto, ON M5S 3E5, Canada
| | - Anjuli M. Szawiola
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, 200 College St., Toronto, ON M5S 3E5, Canada
- Department of Chemistry, University of Toronto, 80 St. George St., Toronto, ON M5S 3H4, Canada
| | - Trevor Plint
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, 200 College St., Toronto, ON M5S 3E5, Canada
| | - Timothy P. Bender
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, 200 College St., Toronto, ON M5S 3E5, Canada
- Department of Chemistry, University of Toronto, 80 St. George St., Toronto, ON M5S 3H4, Canada
- Department of Materials Science and Engineering, University of Toronto, 184 College St., Toronto, ON M5S 3E4, Canada
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15
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Chen X, Yi M, Wu S, Tan L, Ge X, He M, Yin G. Synthesis of Structurally Precise Polysiloxanes via the Piers⁻Rubinsztajn Reaction. MATERIALS (BASEL, SWITZERLAND) 2019; 12:E304. [PMID: 30669375 PMCID: PMC6356218 DOI: 10.3390/ma12020304] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/07/2018] [Revised: 01/08/2019] [Accepted: 01/15/2019] [Indexed: 12/01/2022]
Abstract
Silicone materials are widely used, from daily life to the military industry. With the advancement of science and technology and the increasing demands of industry, the requirement for high-performance precise structural silicone materials has increased. Therefore, the most important aspect in this field is finding a breakthrough in the synthetic methods. In this review, the latest research developments in controllable morphological structure and composite structure optimized synthesis of silicone materials using the Piers⁻Rubinsztajn (PR) reaction are summarized. The advantages of the PR reaction compared with traditional synthetic routes to silicone materials are presented. The highly controllable spatial structure of silicone materials and the structural combination of biomass or inorganic materials with silicone materials results in an improvement in performance or function. The morphological control of more complex silicone materials and the synthesis of non-traditional silicone materials with composite structures through the PR reaction will be the main research directions for the development of silicone materials in the future.
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Affiliation(s)
- Xunjun Chen
- College of Chemistry and Chemical Engineering, Zhongkai University of Agriculture and Engineering, Guangzhou 510225, China.
| | - Minghao Yi
- College of Chemistry and Chemical Engineering, Zhongkai University of Agriculture and Engineering, Guangzhou 510225, China.
| | - Shufang Wu
- College of Chemistry and Chemical Engineering, Zhongkai University of Agriculture and Engineering, Guangzhou 510225, China.
| | - Lewen Tan
- College of Chemistry and Chemical Engineering, Zhongkai University of Agriculture and Engineering, Guangzhou 510225, China.
| | - Xin Ge
- College of Chemistry and Chemical Engineering, Zhongkai University of Agriculture and Engineering, Guangzhou 510225, China.
| | - Ming He
- College of Chemistry and Chemical Engineering, Zhongkai University of Agriculture and Engineering, Guangzhou 510225, China.
| | - Guoqiang Yin
- College of Chemistry and Chemical Engineering, Zhongkai University of Agriculture and Engineering, Guangzhou 510225, China.
- Guangzhou key Laboratory for Efficient Utilization of Agricultural Chemicals, Guangzhou 510225, China.
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16
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Takeshita T, Sato K, Nakajima Y. Selective hydrosiloxane synthesis via dehydrogenative coupling of silanols with hydrosilanes catalysed by Fe complexes bearing a tetradentate PNNP ligand. Dalton Trans 2018; 47:17004-17010. [PMID: 30460962 DOI: 10.1039/c8dt04168g] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
A well-defined iron complex system was established using PNNP-R (R = Ph and Cy) as a strong σ-donating ligand with a rigid meridional tetradentate structure. Reactive Fe(0) complexes [{Fe(PNNP-R)}2(μ-N2)] were synthesized by a reaction of the corresponding iron dihalide with NaBEt3H and structurally characterized. The reaction proceeded via the iron dihydride intermediate [Fe(H)2(PNNP-R)], which underwent H2 reductive elimination, supporting the hemilabile behavior of PNNP-R. [{Fe(PNNP-R)}2(μ-N2)] catalyzed the dehydrogenative coupling of silanols with silanes to selectively form various hydrosiloxanes, which are important building blocks for the synthesis of a range of siloxane compounds. This system exhibited higher catalytic efficiency than the previously reported precious-metal-catalyzed systems.
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Affiliation(s)
- Tomohiro Takeshita
- Interdisciplinary Research Centre for Catalytic Chemistry (IRC3), National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba Central 5, 1-1-1 Higashi, Tsukuba, Ibaraki 305-8565, Japan. and Faculty of Pure and Applied Sciences, University of Tsukuba, 1-1-1 Tennoudai, Tsukuba, Ibaraki 305-8571, Japan
| | - Kazuhiko Sato
- Interdisciplinary Research Centre for Catalytic Chemistry (IRC3), National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba Central 5, 1-1-1 Higashi, Tsukuba, Ibaraki 305-8565, Japan.
| | - Yumiko Nakajima
- Interdisciplinary Research Centre for Catalytic Chemistry (IRC3), National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba Central 5, 1-1-1 Higashi, Tsukuba, Ibaraki 305-8565, Japan. and Faculty of Pure and Applied Sciences, University of Tsukuba, 1-1-1 Tennoudai, Tsukuba, Ibaraki 305-8571, Japan
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17
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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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18
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Liao M, Schneider AF, Laengert SE, Gale CB, Chen Y, Brook MA. Living synthesis of silicone polymers controlled by humidity. Eur Polym J 2018. [DOI: 10.1016/j.eurpolymj.2018.07.023] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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Fabrication of Reactive Poly(Phenyl-Substituted Siloxanes/Silsesquioxanes) with Si‒H and Alkoxy Functional Groups via the Piers⁻Rubinsztajn Reaction. Polymers (Basel) 2018; 10:polym10091006. [PMID: 30960930 PMCID: PMC6403990 DOI: 10.3390/polym10091006] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2018] [Revised: 09/05/2018] [Accepted: 09/06/2018] [Indexed: 11/17/2022] Open
Abstract
Poly(phenyl-substituted siloxanes/silsesquioxanes) are obtained by the Piers⁻Rubinsztajn (PR) reaction of hydrogen-containing siloxanes (HCS) with diphenyldialkoxysilanes such as diphenyldimethoxysilane and diphenyldiethoxysilane catalyzed by tris(pentafluorophenyl)borane. 29Si nuclear magnetic resonance (NMR) spectroscopy, gel permeation chromatography, and refractive index analysis revealed that apart from phenyl substituents and complex structures such as molecular bridges composed of D₂Ph2[(C₆H₅)₂Si(OSi)₂], structures also existed in these polymers, having high refractive indexes (above 1.50) and high molecular weights (75.60 KDa·mol-1). As revealed by thermogravimetric analysis, these polymers have high thermal stability as well, with temperature at 5% mass loss (T5%) increasing by 182.5 °C and Rw (residual weight ratio) increasing by 5.17 times from 14.63% to 75.60%, as compared to HCS, exhibiting its potential application as resins for resisting strong heat. Such high-refractive-index and temperature-resistant poly(phenyl-substituted siloxanes/silsesquioxanes) with Si⁻H and alkoxy functional groups can be used as a good addition-type crosslinking agent with adhesion-promoting properties or a special curing agent that can solidify silicone materials through simultaneous addition and condensation reactions, which has potential application in the light-emitting diode (LED) packaging industry.
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Rubinsztajn S, Cypryk M, Chojnowski J, Fortuniak W, Mizerska U, Pospiech P. Reaction of Silyl Hydrides with Tetrabutoxygermanium in the Presence of B(C6F5)3: Difference between Silicon and Germanium Chemistries and Easy Route to GeH4. Organometallics 2018. [DOI: 10.1021/acs.organomet.8b00156] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Slawomir Rubinsztajn
- Centre of Molecular and Macromolecular Studies, Polish Academy of Sciences, Sienkiewicza 112, 90-363 Lodz, Poland
| | - Marek Cypryk
- Centre of Molecular and Macromolecular Studies, Polish Academy of Sciences, Sienkiewicza 112, 90-363 Lodz, Poland
| | - Julian Chojnowski
- Centre of Molecular and Macromolecular Studies, Polish Academy of Sciences, Sienkiewicza 112, 90-363 Lodz, Poland
| | - Witold Fortuniak
- Centre of Molecular and Macromolecular Studies, Polish Academy of Sciences, Sienkiewicza 112, 90-363 Lodz, Poland
| | - Urszula Mizerska
- Centre of Molecular and Macromolecular Studies, Polish Academy of Sciences, Sienkiewicza 112, 90-363 Lodz, Poland
| | - Piotr Pospiech
- Centre of Molecular and Macromolecular Studies, Polish Academy of Sciences, Sienkiewicza 112, 90-363 Lodz, Poland
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Kaese T, Trageser T, Budy H, Bolte M, Lerner HW, Wagner M. A redox-active diborane platform performs C(sp 3)-H activation and nucleophilic substitution reactions. Chem Sci 2018; 9:3881-3891. [PMID: 29780520 PMCID: PMC5942040 DOI: 10.1039/c8sc00743h] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2018] [Accepted: 03/19/2018] [Indexed: 12/19/2022] Open
Abstract
Targeted C(sp3)–H activation or nucleophilic substitution reactions have been achieved through the interaction of a diborane dianion with haloalkanes.
Organoboranes are among the most versatile and widely used reagents in synthetic chemistry. A significant further expansion of their application spectrum would be achievable if boron-containing reactive intermediates capable of inserting into C–H bonds or performing nucleophilic substitution reactions were readily available. However, current progress in the field is still hampered by a lack of universal design concepts and mechanistic understanding. Herein we report that the doubly arylene-bridged diborane(6) 1H2 and its B
Created by potrace 1.16, written by Peter Selinger 2001-2019
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B-bonded formal deprotonation product Li2[1] can activate the particularly inert C(sp3)–H bonds of added H3CLi and H3CCl, respectively. The first case involves the attack of [H3C]– on a Lewis-acidic boron center, whereas the second case follows a polarity-inverted pathway with nucleophilic attack of the B
Created by potrace 1.16, written by Peter Selinger 2001-2019
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B double bond on H3CCl. Mechanistic details were elucidated by means of deuterium-labeled reagents, a radical clock, α,ω-dihaloalkane substrates, the experimental identification of key intermediates, and quantum-chemical calculations. It turned out that both systems, H3CLi/1H2 and H3CCl/Li2[1], ultimately funnel into the same reaction pathway, which likely proceeds past a borylene-type intermediate and requires the cooperative interaction of both boron atoms.
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Affiliation(s)
- Thomas Kaese
- Institut für Anorganische und Analytische Chemie , Goethe-Universität Frankfurt , Max-von-Laue-Straße 7 , D-60438 Frankfurt am Main , Germany .
| | - Timo Trageser
- Institut für Anorganische und Analytische Chemie , Goethe-Universität Frankfurt , Max-von-Laue-Straße 7 , D-60438 Frankfurt am Main , Germany .
| | - Hendrik Budy
- Institut für Anorganische und Analytische Chemie , Goethe-Universität Frankfurt , Max-von-Laue-Straße 7 , D-60438 Frankfurt am Main , Germany .
| | - Michael Bolte
- Institut für Anorganische und Analytische Chemie , Goethe-Universität Frankfurt , Max-von-Laue-Straße 7 , D-60438 Frankfurt am Main , Germany .
| | - Hans-Wolfram Lerner
- Institut für Anorganische und Analytische Chemie , Goethe-Universität Frankfurt , Max-von-Laue-Straße 7 , D-60438 Frankfurt am Main , Germany .
| | - Matthias Wagner
- Institut für Anorganische und Analytische Chemie , Goethe-Universität Frankfurt , Max-von-Laue-Straße 7 , D-60438 Frankfurt am Main , Germany .
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22
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Brook MA. New Control Over Silicone Synthesis using SiH Chemistry: The Piers-Rubinsztajn Reaction. Chemistry 2018; 24:8458-8469. [PMID: 29468751 DOI: 10.1002/chem.201800123] [Citation(s) in RCA: 79] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2018] [Indexed: 11/11/2022]
Abstract
There is a strong imperative to synthesize polymers with highly controlled structures and narrow property ranges. Silicone polymers do not lend themselves to this paradigm because acids or bases lead to siloxane equilibration and loss of structure. By contrast, elegant levels of control are possible when using the Piers-Rubinsztajn reaction and analogues, in which the hydrophobic, strong Lewis acid B(C6 F5 )3 activates SiH groups, permitting the synthesis of precise siloxanes under mild conditions in high yield; siloxane decomposition processes are slow under these conditions. A broad range of oxygen nucleophiles including alkoxysilanes, silanols, phenols, and aryl alkyl ethers participate in the reaction to create elastomers, foams and green composites, for example, derived from lignin. In addition, the process permits the synthesis of monofunctional dendrons that can be assembled into larger entities including highly branched silicones and dendrimers either using the Piers-Rubinsztajn process alone, or in combination with hydrosilylation or other orthogonal reactions.
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Affiliation(s)
- Michael A Brook
- Department of Chemistry and Chemical Biology, McMaster University, 1280 Main St. W., Hamilton, ON, L8S 4M1, Canada
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24
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Morgan J, Chen T, Hayes R, Dickie T, Urlich T, Brook MA. Facile synthesis of dendron-branched silicone polymers. Polym Chem 2017. [DOI: 10.1039/c7py00260b] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Monofunctional dendritic silicone branches were created from hydro- and alkoxysilanes using the Piers–Rubinsztajn reaction. Monofunctional dendritic silicone branches were added to linear polymers with varied branch frequency, density and backbone molecular weight. Viscosities of the polymers increased with branch frequency to a maximum beyond which the viscosity decreased.
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Affiliation(s)
- Jennifer Morgan
- Department of Chemistry and Chemical Biology
- McMaster University
- Hamilton
- Canada
| | - Tong Chen
- Department of Chemistry and Chemical Biology
- McMaster University
- Hamilton
- Canada
| | - Robin Hayes
- Department of Chemistry and Chemical Biology
- McMaster University
- Hamilton
- Canada
| | - Tara Dickie
- Department of Chemistry and Chemical Biology
- McMaster University
- Hamilton
- Canada
| | - Tomas Urlich
- Department of Chemistry and Chemical Biology
- McMaster University
- Hamilton
- Canada
| | - Michael A. Brook
- Department of Chemistry and Chemical Biology
- McMaster University
- Hamilton
- Canada
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25
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von Grotthuss E, Diefenbach M, Bolte M, Lerner HW, Holthausen MC, Wagner M. Reversible Dihydrogen Activation by Reduced Aryl Boranes as Main-Group Ambiphiles. Angew Chem Int Ed Engl 2016. [DOI: 10.1002/ange.201608324] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Esther von Grotthuss
- Institut für Anorganische Chemie; Goethe-Universität Frankfurt; Max-von-Laue-Strasse 7 60438 Frankfurt (Main) Germany
| | - Martin Diefenbach
- Institut für Anorganische Chemie; Goethe-Universität Frankfurt; Max-von-Laue-Strasse 7 60438 Frankfurt (Main) Germany
| | - Michael Bolte
- Institut für Anorganische Chemie; Goethe-Universität Frankfurt; Max-von-Laue-Strasse 7 60438 Frankfurt (Main) Germany
| | - Hans-Wolfram Lerner
- Institut für Anorganische Chemie; Goethe-Universität Frankfurt; Max-von-Laue-Strasse 7 60438 Frankfurt (Main) Germany
| | - Max C. Holthausen
- Institut für Anorganische Chemie; Goethe-Universität Frankfurt; Max-von-Laue-Strasse 7 60438 Frankfurt (Main) Germany
| | - Matthias Wagner
- Institut für Anorganische Chemie; Goethe-Universität Frankfurt; Max-von-Laue-Strasse 7 60438 Frankfurt (Main) Germany
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26
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von Grotthuss E, Diefenbach M, Bolte M, Lerner HW, Holthausen MC, Wagner M. Reversible Dihydrogen Activation by Reduced Aryl Boranes as Main-Group Ambiphiles. Angew Chem Int Ed Engl 2016; 55:14067-14071. [DOI: 10.1002/anie.201608324] [Citation(s) in RCA: 73] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2016] [Indexed: 01/29/2023]
Affiliation(s)
- Esther von Grotthuss
- Institut für Anorganische Chemie; Goethe-Universität Frankfurt; Max-von-Laue-Strasse 7 60438 Frankfurt (Main) Germany
| | - Martin Diefenbach
- Institut für Anorganische Chemie; Goethe-Universität Frankfurt; Max-von-Laue-Strasse 7 60438 Frankfurt (Main) Germany
| | - Michael Bolte
- Institut für Anorganische Chemie; Goethe-Universität Frankfurt; Max-von-Laue-Strasse 7 60438 Frankfurt (Main) Germany
| | - Hans-Wolfram Lerner
- Institut für Anorganische Chemie; Goethe-Universität Frankfurt; Max-von-Laue-Strasse 7 60438 Frankfurt (Main) Germany
| | - Max C. Holthausen
- Institut für Anorganische Chemie; Goethe-Universität Frankfurt; Max-von-Laue-Strasse 7 60438 Frankfurt (Main) Germany
| | - Matthias Wagner
- Institut für Anorganische Chemie; Goethe-Universität Frankfurt; Max-von-Laue-Strasse 7 60438 Frankfurt (Main) Germany
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27
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Pigaleva MA, Elmanovich IV, Temnikov MN, Gallyamov MO, Muzafarov AM. Organosilicon compounds in supercritical carbon dioxide: Synthesis, polymerization, modification, and production of new materials. POLYMER SCIENCE SERIES B 2016. [DOI: 10.1134/s1560090416030118] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Zhang Z, Feng S, Zhang J. Facile and Efficient Synthesis of Carbosiloxane Dendrimers via Orthogonal Click Chemistry Between Thiol and Ene. Macromol Rapid Commun 2015; 37:318-22. [PMID: 26676283 DOI: 10.1002/marc.201500607] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2015] [Revised: 11/13/2015] [Indexed: 01/22/2023]
Abstract
A combination of a thiol-Michael addition reaction and a free radical mediated thiol-ene reaction is employed as a facile and efficient approach to carbosiloxane dendrimer synthesis. For the first time, carbosiloxane dendrimers are constructed rapidly by an orthogonal click strategy without protection/deprotection procedures. The chemoselectivity of these two thiol-ene click reactions leads to a design of a new monomer containing both electron-deficient carbon-carbon double bonds and unconjugated carbon-carbon double bonds. Siloxane bonds are introduced as the linker between these two kinds of carbon-carbon double bonds. Starting from a bifunctional thiol core, the dendrimers are constructed by iterative thiol-ene click reactions under different but both mild reaction conditions. After simple purification steps the fifth dendrimer with 54 peripheral functional groups is obtained with an excellent overall yield in a single day. Furthermore, a strong blue glow is observed when the dendrimer is excited by a UV lamp.
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Affiliation(s)
- Zhida Zhang
- Key Laboratory of Special Functional Aggregated Materials and Key Laboratory of Colloid and Interface Chemistry, Ministry of Education, School of Chemistry and Chemical Engineering, Shandong University, Jinan, 250100, P. R. China
| | - Shengyu Feng
- Key Laboratory of Special Functional Aggregated Materials and Key Laboratory of Colloid and Interface Chemistry, Ministry of Education, School of Chemistry and Chemical Engineering, Shandong University, Jinan, 250100, P. R. China
| | - Jie Zhang
- Key Laboratory of Special Functional Aggregated Materials and Key Laboratory of Colloid and Interface Chemistry, Ministry of Education, School of Chemistry and Chemical Engineering, Shandong University, Jinan, 250100, P. R. China
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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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