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

Reaction of Co 2 (CO) 8 with the Si−H-functionalized sila[1]ferrocenophane Fe( η -C 5 H 4 ) 2 SiMeH ( 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 -C 5 H 5 )Fe( η -C 5 H 4 )Si[μ-Co 2 (CO) 7 ](Me) 6 in 45% yield. The novel red, crystalline sila[1]ferrocenophane Fe( η -C 5 H 4 ) 2 Si[Co(CO) 4 ](Me) ( 8 ), the first with a direct Si−M bond, was isolated in 23% yield when the reaction between 1a and Co 2 (CO) 8 was conducted in NEt 3 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 -C 5 H 4 ) 2 Si(Et)(H) ( 9 ) and Fe( η -C 5 H 4 ) 2 Si(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 Co 2 (CO) 8 showed only the presence of ( η -C 5 H 5 )Fe( η -C 5 H 4 )Si[μ-Co 2 (CO) 7 ](Et) ( 11 ) and ( η -C 5 H 4 D)Fe( η -C 5 H 4 )Si[μ-Co 2 (CO) 7 ](Me) ( 12 ); neither ( η -C 5 H 4 D)Fe( η -C 5 H 4 )Si[μ-Co 2 (CO) 7 ](Et) ( 11 ‘) nor ( η -C 5 H 5 )Fe( η -C 5 H 4 )Si[μ-Co 2 (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.