Phosphine-Stabilized Digermavinylidene.

An intramolecular germylene-phosphine Lewis pair (1) was reacted with germanium dichloride to give in 92% yield a phosphine adduct of a chloro substituted germyl-germylene (2). After reduction of this dichloride with strong reductants like the Mg(I) reagent {(Nacnac)Mg} (72% yield) or Na (52% yield) a phosphine stabilized digermavinylidene (3) was isolated as crystalline material [Nacnac = {[(Mes)NC(Me)]CH}, Mes = 2,4,6-MeCH]. The electronic structure of the digermavinylidene was investigated by density functional theory calculations. In reaction with adamantylphosphaalkyne the product of a [2+2] cycloaddition was characterized (4). Adamantylazide abstracts at room temperature a germanium atom from the digermavinylidene and a tetrameric organogermanium nitride (5) was isolated as colorless crystals.