High‐Throughput Synthesis and Characterization of Aryl Silicones by Using the Piers–Rubinsztajn Reaction

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.

Use of Piers–Rubinsztajn Chemistry to Access Unique and Challenging Silicon Phthalocyanines

“…We have previously demonstrated the use of PR chemistry in coupling triarylamines to siloxane oligomers or polymers for the generation of new materials. − This type of chemistry has also been used to make many other functional materials such as siloxane-based foams, , surfactants, cross-linkers with lignin, elastomers, , polymers, − dendrons, , and other unique cyclic macrocycles . The PR reaction uses tris­(pentafluorophenyl)­borane as an organic Lewis acid catalyst, coupling a Si–H bond to an oxygen-based nucleophile and then forming a Si–O bond. − Examples of oxygen-based nucleophiles include hydroxy (−OH) and ether (−OR) groups and yield hydrogen (H 2 ) or methane (CH 4 ) as a byproduct.…”

Hyperbranched Polycarbosiloxanes: Synthesis by Piers-Rubinsztajn Reaction and Application as Precursors to Magnetoceramics

“…In particular, developing Si-HBPs via simple, rapid and mild synthetic procedures is highly desirable. The Piers-Rubinsztajn (P-R) reaction, namely the condensation of alkoxysilanes with hydrosilanes, has rapidly developed since it was found in the 1990s [22,23], because this strategy is mild and provides a possibility for the controlled or precise synthesis of silicones, including small molecules, linear polymers, and crosslinked materials [24][25][26][27][28][29][30][31]. For example, the P-R coupling reactions of various organic tris(dimethylsiloxy)silane and trialkoxysilane compounds can generate a series of cyclic polysiloxanes with cyclotetrasiloxane subunits in a simple one-step synthesis [32].…”

The ultimate Lewis acid catalyst: using tris(pentafluorophenyl) borane to create bespoke siloxane architectures

“…In 2019, Brook and co-workers showed that the synthesis of siloxanes using this method can occur using a high-throughput strategy with the aid of a robot. 39 Many of the structures in Scheme 3 contain extra functionality in the form of substituted aryl groups or vinyl groups which allow for post-Piers-Rubinsztajn secondary reactions, e.g. curing the groups via heat-induced radical polymerization.…”