Reactions of the Si−H Functionalized Silicon-Bridged [1]Ferrocenophane Fe(η-C5H4)2SiMeH with Dicobalt Octacarbonyl: Ring-Opening Metalization and the Synthesis of a Novel Sila[1]ferrocenophane with a Co(CO)4 Substituent
Citations Over TimeTop 16% of 2001 papers
Abstract
Reaction of Co2(CO)8 with the Si−H-functionalized sila[1]ferrocenophane Fe(η-C5H4)2SiMeH (1a) was found to result in metalation of silicon and ring-opening of the ferrocenophane, affording the orange crystalline silylene-bridged dicobalt heptacarbonyl complex (η-C5H5)Fe(η-C5H4)Si[μ-Co2(CO)7](Me) 6 in 45% yield. The novel red, crystalline sila[1]ferrocenophane Fe(η-C5H4)2Si[Co(CO)4](Me) (8), the first with a direct Si−M bond, was isolated in 23% yield when the reaction between 1a and Co2(CO)8 was conducted in NEt3 as a proton trap. The dinuclear complex 6 and metalated silicon-bridged ferrocenophane 8 were each characterized by multinuclear NMR spectroscopy, mass spectrometry, and single-crystal X-ray diffraction. [1]Ferrocenophanes Fe(η-C5H4)2Si(Et)(H) (9) and Fe(η-C5H4)2Si(Me)(D) (10) were prepared in order to investigate whether the ring-opening reaction that afforded 6 was an intramolecular or an intermolecular process. Mass spectral analysis of the products of the reaction of an equimolar mixture of 9 and 10 with Co2(CO)8 showed only the presence of (η-C5H5)Fe(η-C5H4)Si[μ-Co2(CO)7](Et) (11) and (η-C5H4D)Fe(η-C5H4)Si[μ-Co2(CO)7](Me) (12); neither (η-C5H4D)Fe(η-C5H4)Si[μ-Co2(CO)7](Et) (11‘) nor (η-C5H5)Fe(η-C5H4)Si[μ-Co2(CO)7](Me) (12‘) were detected, which indicated that the ring-opening process was intramolecular. Compounds 11 and 12 were synthesized separately to provide comparative spectroscopic data for the mechanistic investigation.
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