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Okayama Y, Eom T, Czuczola M, Abdilla A, Blankenship JR, Albanese KR, de Alaniz JR, Bates CM, Hawker CJ. Heterotelechelic Silicones: Facile Synthesis and Functionalization Using Silane-Based Initiators. Macromolecules 2023; 56:8806-8812. [PMID: 38024157 PMCID: PMC10653272 DOI: 10.1021/acs.macromol.3c01802] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2023] [Revised: 10/09/2023] [Accepted: 10/16/2023] [Indexed: 12/01/2023]
Abstract
The synthetic utility of heterotelechelic polydimethylsiloxane (PDMS) derivatives is limited due to challenges in preparing materials with high chain-end fidelity. In this study, anionic ring-opening polymerization (AROP) of hexamethylcyclotrisiloxane (D3) monomers using a specifically designed silyl hydride (Si-H)-based initiator provides a versatile approach toward a library of heterotelechelic PDMS polymers. A novel initiator, where the Si-H terminal group is connected to a C atom (H-Si-C) and not an O atom (H-Si-O) as in traditional systems, suppresses intermolecular transfer of the Si-H group, leading to heterotelechelic PDMS derivatives with a high degree of control over chain ends. In situ termination of the D3 propagating chain end with commercially available chlorosilanes (alkyl chlorides, methacrylates, and norbornenes) yields an array of chain-end-functionalized PDMS derivatives. This diversity can be further increased by hydrosilylation with functionalized alkenes (alcohols, esters, and epoxides) to generate a library of heterotelechelic PDMS polymers. Due to the living nature of ring-opening polymerization and efficient initiation, narrow-dispersity (Đ < 1.2) polymers spanning a wide range of molar masses (2-11 kg mol-1) were synthesized. With facile access to α-Si-H and ω-norbornene functionalized PDMS macromonomers (H-PDMS-Nb), the synthesis of well-defined supersoft (G' = 30 kPa) PDMS bottlebrush networks, which are difficult to prepare using established strategies, was demonstrated.
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Affiliation(s)
- Yoichi Okayama
- Materials
Research Laboratory, University of California, Santa Barbara, California 93106, United States
| | - Taejun Eom
- Materials
Research Laboratory, University of California, Santa Barbara, California 93106, United States
| | - Michael Czuczola
- Department
of Chemistry & Biochemistry, University
of California, Santa Barbara, California 93106, United States
| | - Allison Abdilla
- Department
of Chemistry & Biochemistry, University
of California, Santa Barbara, California 93106, United States
| | - Jacob R. Blankenship
- Materials
Research Laboratory, University of California, Santa Barbara, California 93106, United States
- Department
of Chemistry & Biochemistry, University
of California, Santa Barbara, California 93106, United States
| | - Kaitlin R. Albanese
- Materials
Research Laboratory, University of California, Santa Barbara, California 93106, United States
- Department
of Chemistry & Biochemistry, University
of California, Santa Barbara, California 93106, United States
| | - Javier Read de Alaniz
- Department
of Chemistry & Biochemistry, University
of California, Santa Barbara, California 93106, United States
| | - Christopher M. Bates
- Materials
Research Laboratory, University of California, Santa Barbara, California 93106, United States
- Department
of Chemistry & Biochemistry, University
of California, Santa Barbara, California 93106, United States
- Materials
Department, University of California, Santa Barbara, California 93106, United States
- Department
of Chemical Engineering, University of California, Santa Barbara, California 93106, United States
| | - Craig J. Hawker
- Materials
Research Laboratory, University of California, Santa Barbara, California 93106, United States
- Department
of Chemistry & Biochemistry, University
of California, Santa Barbara, California 93106, United States
- Materials
Department, University of California, Santa Barbara, California 93106, United States
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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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