Parent heavy methylenes: Chemical tricks to access isolable complexes of elusive H₂E: Species (E=Ge and Sn)

A milestone in main-group chemistry: Elusive heavy methylene analogues:EH₂ (E=Ge and Sn) were tamed to give isolable species. This feat was achieved by applying the concept of donor-acceptor stabilization: concomitant coordination of a transition metal or monoborane as a Lewis acid and of an N-heterocyclic carbene as a Lewis base (see scheme).