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Melendez-Zamudio M, Silverthorne KEC, Brook MA. High Refractive Index, Enantiopure Silicones Based on BINOL. Macromol Rapid Commun 2022; 43:e2200022. [PMID: 35218259 DOI: 10.1002/marc.202200022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2022] [Revised: 02/10/2022] [Indexed: 11/06/2022]
Abstract
The high refractive index aromatic compound, binaphthol (BINOL), is readily incorporated into silicone polymer chains using the Piers-Rubinsztajn reaction; alternating and random linear copolymers, and elastomers are available. The highest refractive index (RI) materials were BINOL rich. It was not possible to directly make high refractive index linear polymers with very short HSi-capped, telechelic silicone chains, as they did not react cleanly. However, chain extending short vinyl-capped BINOL macromers with simple arylsilanes using hydrosilylation led to polymers with molar mass up to 8000 and refractive indices up to 1.58. Elastomers were prepared using similar processes. The reactions are facile to practice and suggest BINOL could be harnessed in these and other processes to augment RI. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Miguel Melendez-Zamudio
- Department of Chemistry & Chemical Biology, McMaster University, 1280 Main St., W., Hamilton, ON, L8S 4M1, Canada
| | - Kaitlyn E C Silverthorne
- Department of Chemistry & Chemical Biology, McMaster University, 1280 Main St., W., Hamilton, ON, L8S 4M1, Canada
| | - Michael A Brook
- Department of Chemistry & Chemical Biology, McMaster University, 1280 Main St., W., Hamilton, ON, L8S 4M1, Canada
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Bravo-Flores I, Meléndez-Zamudio M, Guerra-Contreras A, Ramírez-Oliva E, Álvarez-Guzmán G, Zárraga-Núñez R, Villegas A, Cervantes J. Revisiting the System Silanes-Polysaccharides: The Cases of THEOS-Chitosan and MeTHEOS-Chitosan. Macromol Rapid Commun 2021; 42:e2000612. [PMID: 33458894 DOI: 10.1002/marc.202000612] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2020] [Revised: 11/27/2020] [Indexed: 01/14/2023]
Abstract
The glycol alkoxysilanes, tetrakis(2-hydroxyethyl)silane (THEOS), and tris(2-hydroxyethyl)methyl silane (MeTHEOS) are water soluble derivatives of tetraethoxysilane (TEOS) and methyltriethoxysilane (MeTEOS) and precursors of the system silane-chitosan reviewed in this work. The glycol modified alkoxysilanes are obtained by transesterification reaction of TEOS or MeTEOS with ethylene glycol. The reaction evolution is monitored by 29 Si NMR. It is possible to observe the formation of the various species of glycol alkoxysilanes in equilibrium as the reaction proceeds showing that the oligomers formation is favored at longer reaction times with the final product tendency to gel keeping the complete water solubility. The glycol alkoxysilanes are synthesized at moderated reaction conditions, by using the Piers-Rubinsztajn (PR) reaction. Additionally, it is already known that THEOS is compatible with different natural polysaccharides as chitosan and the same behavior has been demonstrated in this work for MeTHEOS. Several reports refer studies regarding the system THEOS-polysaccharides to synthesize hybrid materials. The system THEOS-chitosan is known but the characterization as well as the way silane-chitosan interact has not been studied in detail. In the present report, chemical evidence of the covalent interactions THEOS- and MeTHEOS-chitosan based on NMR studies (13 C and 29 Si) are presented as intended.
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Affiliation(s)
- Ileana Bravo-Flores
- Departamento de Química, División de Ciencias Naturales y Exactas, Universidad de Guanajuato, Noria Alta S/N, Guanajuato, 36050, México
| | - Miguel Meléndez-Zamudio
- Department of Chemistry and Chemical Biology, McMaster University, 1280 Main St. W., Hamilton, ON, L8S 4M, Canada
| | - Antonio Guerra-Contreras
- Departamento de Química, División de Ciencias Naturales y Exactas, Universidad de Guanajuato, Noria Alta S/N, Guanajuato, 36050, México
| | - Eulalia Ramírez-Oliva
- Departamento de Química, División de Ciencias Naturales y Exactas, Universidad de Guanajuato, Noria Alta S/N, Guanajuato, 36050, México
| | - Gilberto Álvarez-Guzmán
- Departamento de Química, División de Ciencias Naturales y Exactas, Universidad de Guanajuato, Noria Alta S/N, Guanajuato, 36050, México
| | - Ramón Zárraga-Núñez
- Departamento de Química, División de Ciencias Naturales y Exactas, Universidad de Guanajuato, Noria Alta S/N, Guanajuato, 36050, México
| | - Antonio Villegas
- Departamento de Química, División de Ciencias Naturales y Exactas, Universidad de Guanajuato, Noria Alta S/N, Guanajuato, 36050, México
| | - Jorge Cervantes
- Departamento de Química, División de Ciencias Naturales y Exactas, Universidad de Guanajuato, Noria Alta S/N, Guanajuato, 36050, México
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Goncharova IK, Tukhvatshin RS, Kholodkov DN, Novikov RA, Solodilov VI, Arzumanyan AV. Dumbbell-Shaped, Graft and Bottlebrush Polymers with All-Siloxane Nature: Synthetic Methodology, Thermal, and Rheological Behavior. Macromol Rapid Commun 2020; 42:e2000645. [PMID: 33345394 DOI: 10.1002/marc.202000645] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Revised: 12/04/2020] [Indexed: 12/14/2022]
Abstract
A methodology for synthesizing a wide range of dumbbell-shaped, graft and bottlebrush polymers with all-siloxane nature (without carbosilane linkers) is suggested. These macroarchitectures are synthesized from SiOH-containing compounds-silanol (Et3 SiOH) and siloxanol dendrons of the first and second generations, with various peripheral substituents (Me or Et)-and from linear siloxanes comprising terminal and internal SiH groups by the Piers-Rubinsztajn reaction. Products and key building blocks are obtained in yields up to 95%. These polymers are heat and frost-resistant siloxanes. As it turns out, the product physical properties are determined not only by the macromolecular structure, the linear chain length, the size and frequency of branched pendant, but also by the type of peripheral substituents-Me or Et-in the pendant. Thus, the viscosity of the graft polymers with branched pendant groups comprising peripheral Me-groups is more than ≈3-5 fold lower than that of analogous polymers with peripheral Et-groups.
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Affiliation(s)
- Irina K Goncharova
- Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, 28 Vavilov Street, Moscow, 119991, Russian Federation
| | - Rinat S Tukhvatshin
- Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, 28 Vavilov Street, Moscow, 119991, Russian Federation
| | - Dmitry N Kholodkov
- Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, 28 Vavilov Street, Moscow, 119991, Russian Federation
| | - Roman A Novikov
- Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, 47 Leninsky Pr., Moscow, 119991, Russian Federation
| | - Vitaliy I Solodilov
- Semenov Federal Research Center For Chemical Physics Russian Academy of Sciences, 4 Kosygin Street, Moscow, 119991, Russian Federation
| | - Ashot V Arzumanyan
- Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, 28 Vavilov Street, Moscow, 119991, Russian Federation
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Abstract
Most silicone elastomers are thermosets. As a response to the new paradigm of polymer recyclability, the development of silicone elastomers that can be reversibly and repeatedly cured and uncrosslinked using redox conditions is reported. Thiopropyl-modified silicones are oxidized to elastomers with disulfide crosslinks using the organosoluble oxidant PhI(OAc)2 . As with any elastomer, mechanical properties can be tuned by varying crosslink density. Thermal stabilities in air show that the products are comparable to traditional silicone thermosets, with degradation only starting over 300 °C. Uncrosslinking back to the same thiopropyl-modified silicones involves reductive S-S bridge cleavage using a Piers-Rubinsztajn reaction with hydrosilanes catalyzed by B(C6 F5 )3 ; HSiMe2 OSiMe3 is identified as a convenient reducing agent. The initially formed silicone-(CH2 )3 S-SiMe2 OSiMe3 products need deprotection with water in isopropanol/water to completely regenerate the thiopropylsilicones. This oxidation/reduction crosslinking/uncrosslinking cycle is practiced thrice, with a yield of 89% per cycle, with essentially no change in the Young's moduli of the elastomers, or 1 H NMR spectra of the uncrosslinked fluids after reduction. Further oxidation of disulfide groups on the elastomer surface permanently and significantly improved water wettability.
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Affiliation(s)
- Sijia Zheng
- Department of Chemistry and Chemical Biology, McMaster University, 1280 Main St. W., Hamilton, ON, L8S 4M1, Canada
| | - Michael A Brook
- Department of Chemistry and Chemical Biology, McMaster University, 1280 Main St. W., Hamilton, ON, L8S 4M1, Canada
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Schneider AF, Brook MA. High-Throughput Synthesis and Characterization of Aryl Silicones by Using the Piers-Rubinsztajn Reaction. Chemistry 2019; 25:15367-15374. [PMID: 31595999 DOI: 10.1002/chem.201903658] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2019] [Revised: 09/16/2019] [Indexed: 11/07/2022]
Abstract
Arylsilicones are widely exploited for their thermal and optical properties. The creation of phenylsilicone elastomers with specific physical properties is typically done by a "one-off" formulation and test process. Herein, it is demonstrated that high-throughput synthesis methods can be used to rapidly prepare a series of arylsilicone elastomers and then the relative impact of different aryl groups on their physical properties is assessed. Aromatic groups were incorporated into polydimethylsiloxane (PDMS) elastomers by exploiting the relative reactivity of different functional groups in the Piers-Rubinsztajn reaction. To analyze trends in the silicone mechanical properties as a function of increasing aryl concentration-structure/property relationships-libraries of elastomers were both quickly synthesized and characterized by using high-throughput suites starting from low viscosity silicone oils/monomers in 96-well plates. Liquid handling parameters were optimized to effectively work with the silicones. Incorporating aryl instead of alkyl crosslinkers into the PDMS backbone increased the silicone elastomer modulus by approximately 50 % (at a crosslink density of 6 %); elastomers prepared with an aromatic crosslinker with three contact points led to much higher moduli compared with those with one contact point at the same crosslink density. When located at precise rather than random points on the silicone chains, diphenylsilicones had lower moduli than analogous monophenylsilicones.
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Affiliation(s)
- Alyssa F Schneider
- Department of Chemistry and Chemical Biology, McMaster University, 1280 Main Street West, Hamilton, ON, L8S 4M1, Canada
| | - Michael A Brook
- Department of Chemistry and Chemical Biology, McMaster University, 1280 Main Street West, Hamilton, ON, L8S 4M1, Canada
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Wakabayashi R, Kuroda K. Siloxane-Bond Formation Promoted by Lewis Acids: A Nonhydrolytic Sol-Gel Process and the Piers-Rubinsztajn Reaction. Chempluschem 2013; 78:764-774. [PMID: 31986688 DOI: 10.1002/cplu.201300027] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2013] [Revised: 05/09/2013] [Indexed: 11/06/2022]
Abstract
Siloxane formation reactions of both the nonhydrolytic sol-gel process and Piers-Rubinsztajn reaction can be integrated as Lewis acid promoted siloxane syntheses without involving silanol groups. The former was developed in the field of inorganic materials chemistry and the latter was initiated in polymer chemistry. We have realized both reactions are quite similar, in terms of 1) the nonhydrolytic reaction, 2) the use of alkoxysilanes, 3) the group-exchange reactions competing with the siloxane formation, and 4) the proposed reaction mechanisms. This Minireview focuses on the above two reactions. The evolution of both reactions should realize a more sophisticated molecular design of siloxane compounds, which surely contributes to the development of advanced functional materials.
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Affiliation(s)
- Ryutaro Wakabayashi
- Department of Applied Chemistry, Waseda University, Ohkubo-3, Shinjuku-ku, Tokyo 169-8555 (Japan), Fax: (+81) 3-5286-3199 http://www.waseda.jp/sem-kuroda_lab/.,Kagami Memorial Research Institute for Materials, Science and Technology, Waseda University, Nishiwaseda-2, Shinjuku-ku, Tokyo 169-0051 (Japan).,Research Fellow Laboratories Yokkaichi, JSR Corporation, 100 Kawajiri-cho, Yokkaichi, Mie 510-8552 (Japan)
| | - Kazuyuki Kuroda
- Department of Applied Chemistry, Waseda University, Ohkubo-3, Shinjuku-ku, Tokyo 169-8555 (Japan), Fax: (+81) 3-5286-3199 http://www.waseda.jp/sem-kuroda_lab/.,Kagami Memorial Research Institute for Materials, Science and Technology, Waseda University, Nishiwaseda-2, Shinjuku-ku, Tokyo 169-0051 (Japan)
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