Synthesis and characterization of π cyclopentadienyl complexes of manganese and iron with one to five fluorosilyl substituents. Crystal and molecular structures of [Mn(C5Br{SiMe2F}4)(CO)3] and [Mn(C5{SiMe2F}5)(CO)3]

Abstract

The reaction of AgSbF₆ with the cymantrenyl hydrosilanes [Mn{C₅Br_5−n(SiMe₂H)_n}(CO)₃] (n = 1–5) gives the corresponding fluorosilanes. With the ferrocenylhydrosilanes [Fe{C₅Br_5−n(SiMe₂H)_n}(C₅H₅)] fluorination and oxidation to give the ferricenium salts [Fe{C₅Br_5−n(SiMe₂F)_n}(C₅H₅)]⁺SbF₆⁻ (n = 1–5) occurs. Reaction of the latter with cobaltocene gives the corresponding neutral fluorosilanes. All compounds were characterized by a combination of NMR methods (¹H, ¹³C{¹H} and ¹⁹F; sometimes also ²⁹Si) and in part as well by IR and HR mass spectrometry. The reactivity of the cymantrenyl fluorosilanes towards carbanions and MeOH was studied. X-ray diffraction analysis of [Mn{C₅Br_5−n(SiMe₂F)_n}(CO)₃] (n = 4–5) shows paddle-wheel orientations of the SiMe₂F groups.