LAUSR

Abstract Reaction of hydrido(hydrogermylene) complex Cp*(CO) 2 (H)W=Ge(H)(Tsi) ( 1 , Tsi = C(SiMe 3 ) 3 ) with 1 equiv of Me IMe ( Me IMe = 1,3-dimethyl-4,5-dimethylimidazol-2-ylidene) immediately afforded NHC-stabilized germylene complex Cp*(CO) 2 (H)WGe(H)( Me IMe)(Tsi) ( 2 ) that has a zwitterionic, W–Ge single-bonded structure. Complex 2 was thermally unstable and intramolecular proton-transfer followed by hydride-transfer to the NHC-unit occurred slowly at room temperature to give anionic germylene complex [Cp*(CO) 2 W=Ge(H)(Tsi)][H Me IMe] ([ 3 ][H Me IMe]) first and subsequently germylyne complex Cp*(CO) 2 W≡Ge(Tsi) ( 4 ) and H 2 Me IMe. Although [ 3 ][H Me IMe] was too unstable to be isolated, the salt of bulkier [H Me I i Pr] + , [Cp*(CO) 2 W=Ge(H)(Tsi)][H Me I i Pr] ([ 3 ][H Me I i Pr]), was thermally more stable and was isolated and fully characterized.