Stable Complexes of Parent Digermene: An Inorganic Analogue of Ethylene

The elusive parent inorganic ethylene H2GeGeH2 has been isolated in the form of a stable complex for the first time via donor–acceptor coordination with suitable Lewis base/acid combinations (LB·H2Ge-GeH2·LA; LB = N-heterocyclic carbene or N-heterocyclic olefin; LA = W­(CO)5). The nature of the bonding in these species was investigated by density functional theory calculations and revealed the presence of polarized Ge–Ge covalent σ-bonds within the H2Ge–GeH2 arrays and dative Ge–C interactions between the digermene and the carbon-based Lewis bases.