Selective Route to Stable Silicon-Boron Radicals and Their Corresponding Cations.

Herein, we report on a facile and selective one-pot synthetic route to silicon-boron radicals. Reduction of BrBTip (Tip = 2,4,6-PrCH) with KC in the presence of LSi-R affords LSi(Bu)-B(Br)Tip () and LSi(N(TMS))-B(Br)Tip () [L = PhC(NBu)]. These first examples of silicon-boron isolated radical species feature spin density on the silicon and boron atoms. and exhibit extraordinary stability to high temperatures under inert conditions in solution and air stability in the solid state. Both radicals have been isolated and fully characterized by electron paramagnetic resonance spectroscopy, SQUID magnetometry, mass spectrometry, cyclic voltammetry, single-crystal X-ray structure analysis, and density functional theory calculations. Moreover, compound exhibits one-electron transfer when treated with 1 equiv of AgSOCF and [PhC][B(CF)], respectively, resulting in the corresponding cations [LSi(Bu)-B(Br)Tip][CFSO] () and [LSi(Bu)-B(Br)Tip][B(CF)] (). Compounds and have been characterized with multinuclear NMR and mass spectrometry.