Germanium Hydride Radical Trapped during the Photolysis/Thermolysis of Diarylgermylene

Herein, we report the characterization of a novel germanium hydride radical arising from the photolysis/thermolysis of the diarylgermylene GeR2 [R = terphenyl: AriPr4 = C6H3-2,6-(C6H3-2,6-iPr2)2 or AriPr6 = C6H3-2,6-(C6H2-2,4,6-iPr3)2] by using electron paramagnetic resonance spectroscopy complemented with theoretical calculations. The trapped germanium radical is a pseudoplanar S = 1/2 germanium(III) hydride, i.e., •GeHRR' (R = AriPr4 or AriPr6; R' is a quaternary carbon), with a g 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.