Amidinato Germylene-Zinc Complexes: Synthesis, Bonding, and Reactivity.

Despite the explosive growth of germylene compounds as ligands in transition metal complexes, there is a modicum of precedence for the germylene zinc complexes. In this work, the synthesis and characterization of new germylene zinc complexes [PhC(NtBu) Ge{N(SiMe ) }→ZnX ] (X= Br (2) and I (3)) supported by (benz)-amidinato germylene ligands are reported. The solid-state structures of 2 and 3 have been validated by single-crystal X-ray diffraction studies, which revealed the dimeric nature of the complexes, with distorted tetrahedral geometries around the Ge and Zn center. DFT calculations reveal that the Ge-Zn bonds in 2 and 3 are dative in nature. The reaction of 2 with elemental sulfur resulted in the first structurally characterized germathione stabilized ZnBr complexes PhC(NtBu) Ge(=S){N(SiMe ) }→ZnBr (5). Therefore, the Ge=S in 5 is in-between Ge-S single and Ge=S double bond length, owing to the coordination of a sulfur lone pair of electrons to ZnBr .