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

Abstract

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 (ΔG_iso(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.