Photo Lewis acid generators: photorelease of B(C6F5)3 and applications to catalysis

A series of molecules capable of releasing of the strong organometallic Lewis acid B(C6F5)3 upon exposure to 254 nm light have been developed. These photo Lewis acid generators (PhLAGs) can now serve as photoinitiators for several important B(C6F5)3-catalyzed reactions. Herein is described the synthesis of the triphenylsulfonium and diphenyliodonium salts of carbamato- and hydridoborates, their establishment as PhLAGs, and studies aimed at defining the mechanism of borane release. Factors affecting these photolytic reactions and the application of this concept to photoinduced hydrosilylation reactions and construction of siloxane scaffolds are also discusse

Photo Lewis acid generators: photorelease of B(C6F5)3 and applications to catalysis

A series of molecules capable of releasing of the strong organometallic Lewis acid B(C6F5)3 upon exposure to 254 nm light have been developed. These photo Lewis acid generators (PhLAGs) can now serve as photoinitiators for several important B(C6F5)3-catalyzed reactions. Herein is described the synthesis of the triphenylsulfonium and diphenyliodonium salts of carbamato- and hydridoborates, their establishment as PhLAGs, and studies aimed at defining the mechanism of borane release. Factors affecting these photolytic reactions and the application of this concept to photoinduced hydrosilylation reactions and construction of siloxane scaffolds are also discusse

Comparative Lewis Acidity in Fluoroarylboranes: B(<i>o</i>‑HC₆F₄)₃, B(<i>p</i>‑HC₆F₄)₃, and B(C₆F₅)₃

The Lewis acidic fluoroarylborane B­(<i>o</i>-HC₆F₄)₃ (<b>2</b>) was prepared and its Lewis acid strength assessed in comparison to the known, related boranes B­(C₆F₅)₃ (<b>1</b>) and B­(<i>p</i>-HC₆F₄)₃ (<b>3</b>). Experimental methods based on spectroscopic probes and equilibrium measurements were used to show that B­(C₆F₅)₃ is the strongest Lewis acid of the three; while the Lewis acidities of <b>2</b> and <b>3</b> are comparable, the <i>p</i>-H-substituted isomer is slightly stronger in the tests employed. This contrasts with predictions made on the basis of computed bond formation energies, as recently reported by Durfey and Gilbert