Synthesis and Reactivity of η5-Germacyclopentadienyl Complexes of Iron

Reaction of 2 equiv of the previously reported germolyl anion Li[C 4 Me 4 GeSi(SiMe 3 ) 3 ] with FeCl 2 (THT) 1.5 (THT = tetrahydrothiophene) at low temperature gave the new bis-η 5 -germolyl complex [η 5 -C 4 Me 4 GeSi(SiMe 3 ) 3 ] 2 Fe ( 1 ), which was characterized by X-ray crystallography. Reaction of 1 with I 2 resulted in loss of the germolyl ligand as C 4 Me 4 Ge(I)[Si(SiMe 3 ) 3 ], while the reaction with MeLi produced the ferrocenophane ansa -(Me 3 Si) 2 Si(η 5 -GeC 4 Me 4 ) 2 Fe ( 4 ). X-ray crystallographic analysis of this compound revealed that the Ge atoms are displaced significantly out of the C 4 plane. Attempts to induce the ring-opening polymerization of 4 were unsuccessful.