Transition-Metal Complexes of Heavier Cyclopropenes: Non-Dewar–Chatt–Duncanson Coordination and Facile Si?Ge Functionalization

Transition-metal complexes of cyclopropenes occur as fleeting intermediates numerous metal-catalyzed organic transformations. A heavier analogue has now been obtained from the reaction an NHC-stabilized silagermenylidene, bis(1,5-cyclooctadiene)nickel(0), and 1 equiv N-heterocyclic carbene (NHC). The residual chloro functionality at germanium end coordinated Ge?Si moiety thus formed 1H-disilagermirene is easily exchanged by treatment with anionic nucleophiles, which provides access to a series differently substituted Si2Ge-cyclopropenes nickel in excellent yields. NMR spectroscopic data, X-ray crystallographic analysis, DFT calculations indicate coordination mode different metallacyclopropane ?-complex extremes Dewar–Chatt–Duncanson model: ?-component double bond acts donor acceptor, leaving behind nearly unsupported Si–Ge ?-bond.