Germanium Hydride Radical Trapped during the Photolysis/Thermolysis of Diarylgermylene

Abstract

Herein, we report the characterization of a novel germanium hydride radical arising from the photolysis/thermolysis of the diarylgermylene GeR₂ [R = terphenyl: Ar^<i>i</i>Pr4 = C₆H₃-2,6-(C₆H₃-2,6-^<i>i</i>Pr₂)₂ or Ar^<i>i</i>Pr6 = C₆H₃-2,6-(C₆H₂-2,4,6-^<i>i</i>Pr₃)₂] by using electron paramagnetic resonance spectroscopy complemented with theoretical calculations. The trapped germanium radical is a pseudoplanar <i>S</i> = ¹/₂ germanium(III) hydride, i.e., ^•GeHRR' (R = Ar^<i>i</i>Pr4 or Ar^<i>i</i>Pr6; R' is a quaternary carbon), with a <b>g</b> tensor of [2.029, 2.003, 1.990], a ⁷³Ge hyperfine tensor of [-10, -90, -10] MHz, and a strong ¹H hyperfine tensor of [-23.0, -20.5, -31.5] MHz for the hydride. The germanium(III) hydride radical is a result of the insertion of a germanium(I) radical intermediate (:ĠeR) in a C-H bond, due to the greater reactivity of the germanium(I) radical intermediate in comparison with the tin(I) counterpart that we trapped earlier.