Novel Silicate Platform as Weakly‐Coordinating Anions for Diverse Organometallic and Electrochemical Applications

Abstract

Weakly-coordinating anions (WCAs) are employed in a wide range of applications, but limitations remain, including high reactivity, limited redox window, complicated synthesis, high cost, low solublity, and low structural tunabililty. Herein, we report a new class of WCA based on alkyl or aryl (R) substituted silicates bearing fluorinated pinacolate ligands, “[^RSi^F₂₄]⁻”. Anions bearing a variety of R groups were prepared, enabling facile tuning of sterics and solubility. A range of cations employed in chemical reactivity has been supported by these anions, including ether-free alkali cations, Ag⁺, Ph₃C⁺, Fc⁺, [Ni^I(COD)₂]⁺. [Pd(dppe)(NCMe)Me]⁺ has been generated by salt metathesis or protonation of a metal-alkyl bond, showcasing the ability of the [^RSi^F₂₄]⁻ anions to support applications in coordination chemistry and catalysis. Electrochemical studies on the [Bu₄N]⁺ variant show an exceptionally wide stability window for the [^MeSi^F₂₄]⁻ anion of 7.5 V in MeCN. CV experiments demonstrate reversible Mg deposition and stripping.

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