Isolable Metallo-Germylene and Metallo-Stannylene σ-Complexes with Iron

Conversion of the β-diketiminato Ge(II) chloride LGeCl [L = CH{CMe(NAr)}2, Ar = 2,6-iPr2C6H3] (1) and its tin homologue LSnCl (2) with the anionic iron complex K[Fe(η5-C5H5)(CO)2] leads to the iron-germylene LGeFe(η5-C5H5)(CO)2 (3) and iron-stannylene LSnFe(η5-C5H5)(CO)2 (4), respectively. The compounds 3 amd 4 were characterized by NMR, IR, and UV−vis spectroscopy as well as theoretical studies. The structure of 3 was also determined by X-ray crystallography. The experimental and computed structures show clealy that the Fe−E (E = Ge, Sn) bond is a single bond in compounds 3 and 4. They represent the isolable iron-germylene and -stannylene σ-complexes. Notably, compound 3 is the first example of iron-germylene σ-complexes ever characterized by X-ray analysis.