Reactivity of Germanium(II) Imide toward o-Methoxyphenyl Isoselenocyanate, Iodine, and Hydrogen

Reactivity of the dimeric germanium(II) imide [H,MeArNGe]2 as a platform for preparing 6π biradicaloid systems via oxidative addition transformations is investigated. Treatment of [H,MeArNGe]2 with o-methoxyphenyl isoselenocyanate at 110 °C does not afford the expected 1,4-oxidation product; instead, it leads to the formation of a selenium-containing product [(H,MeArNGe)2Se]2 (1) (80% yield), in which two molecules of the parent complex are bridged by two Se atoms to form a Ge2Se2 ring. The transformation proceeds asymmetrically and corresponds to 2e– oxidation at one Ge center. Reaction with I2 (1-2 equiv) yields doubly- (2) and tetraiodinated (3) complexes (up to 88%) and clearly demonstrates the possibility of multielectron (up to 4e–) transformations preserving the Ge2N2 core. The structures of all products are confirmed by XRD, IR, and NMR spectroscopy (for soluble samples). No reaction with H2 is observed experimentally even at 80 atm and 70 °C. DFT calculations indicate that the process is kinetically prohibited (ΔG ≈ +5.0 kcal/mol; barrier: ~62.0 kcal/mol) and that the 1,4-adducts are thermodynamically less favorable than the 1,1-isomers (ΔGiso(1,1 → 1,4) = 21.3-53.6 kcal/mol). Additionally, products 1-3 are found to exhibit no luminescence, in contrast to the parent complex.