An amidinate-stabilized germatrisilacyclobutadiene ylide

The synthesis and characterization of new amidinate-stabilized germatrisilacyclobutadiene ylides L(3)Si(3)GeL'] (L=PhC(NtBu)(2); L'=?L; ?=Ge (3), Si (7)) are described. Compound 3 was prepared by the reaction of LSi-SiL] (1) with one equivalent of LGe-GeL] (2) in THF. Compound 7 was synthesized by the reaction of 2 with excess 1 in THF. The bisamidinate germylene L(2)Ge:] (4) is a by-product in both reactions. Moreover, compound 7 was prepared by the reaction of 3 with one equivalent of 1 in THF. Compounds 3 and 7 have been characterized by NMR spectroscopy, X-ray crystallography, and theoretical studies. The results show that compounds 3 and 7 are not antiaromatic. The puckered Si(3) Ge four-membered rings in 3 and 7 have a ylide structure, which is stabilized by amidinate ligands and the electron delocalization within the Si(3) Ge four-membered ring.