An unsymmetric substituted digermylene with a Ge(I)-Ge(I) bond and synthesis of a germylene-stannylene with a Ge(I)-Sn(I) bond.

Convenient salt metathesis reaction of the N-heterocyclic germanium(II) nucleophile LGeK(Et(2)O)(2) [L = C(Me)CHC(Me)N(2,6-(i)Pr(2)C(6)H(3))] with the beta-diketiminato Ge(II) chloride L'GeCl [L' = CH{CMe(NR)}(2), R = 2,6-(i)Pr(2)C(6)H(3)] and the tin analogue L'SnCl furnishes the corresponding novel digermylene having a Ge(I)-Ge(I) bond and the first germylene-stannylene with a Ge(I)-Sn(I) bond, respectively; spectroscopic, structural and theoretical analysis of the latter compounds revealed that they bear Ge-M (M = Ge and Sn) sigma bonds with ionic character.