An amidinate-stabilized Germatrisilacyclobutadiene Ylide

Abstract

The synthesis and characterization of new amidinate-stabilized germatrisilacyclobutadiene ylides [L3Si3GeL′] (L=PhC(NtBu)2; L′=ËL; Ë=Ge (3), Si (7)) are described. Compound 3 was prepared by the reaction of [LSi[BOND]SiL] (1) with one equivalent of [LGe[BOND]GeL] (2) in THF. Compound 7 was synthesized by the reaction of 2 with excess 1 in THF. The bisamidinate germylene [L2Ge:] (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 Si3Ge four-membered rings in 3 and 7 have a ylide structure, which is stabilized by amidinate ligands and the electron delocalization within the Si3Ge four-membered ring.