Excellent yield of a variety of silicon-boron radicals and their reactivity.

Herein we report stable silicon-boron radicals of composition LSi(NMe 2 )-B(Br)Tip (1), LSi(NMe 2 )-B(I)Tip (2) LSi( t Bu)-B(I)Tip (3) [L = PhC(N t Bu) 2 ]. They were prepared in high yield using a one pot reaction of LSiR, X 2 BTip and KC 8 in a 1 : 1 : 1 molar ratio (R = t Bu, NMe 2 ; X = Br, I). The reaction of the silicon-boron radical with Br 2 and Se affords the dihalogenated compound LSi( t Bu)-B(Br 2 )Tip (4) and oxidative addition product LSi( t Bu)Se (5). All the compounds were characterized by single-crystal X-ray structural analysis, electron paramagnetic resonance (EPR) analysis, elemental analysis, multinuclear NMR spectroscopy, and mass spectrometry. Quantum chemical calculations show that the B-centered radicals 1-3 are stabilised by hyperconjugative interactions.