Cyclopentadienone and Hydroxycyclopentadienyl Cobalt Complexes from the Reaction of an Alkynylphenylsilane with Co2(CO)8
摘要:
Reaction of dimethyl(pent-1-yn-1-yl)phenylsilane n-PrC CSiMe2Ph (1) with Co-2(CO)(8) in n-heptane or 1,4-dioxane led to the formation of cobalt complexes with carboncarbon bond coupling and insertion of a carbonyl ligand ([2 + 2 + 1] cycloaddition). In both solvents, the compounds (n-PrC CSiMe2Ph)center dot Co-2(CO)(6) (2), {[n-Pr-2(PhMe2Si)(2)C4C=O]Co(CO)(2)}(2) (3), and [n-Pr-2(PhMe2Si)(2)C5OH]Co-(CO)(2) (4) were obtained. In n-heptane, a fourth cobalt complex (5) was isolated as well but could not be identified, while in 1,4-dioxane, metallic cobalt formed instead. The yields of 3 and 4 in 1,4-dioxane were distinctly higher than those in n-heptane (11 and 21% vs 7.5 and 6%). All compounds were characterized by spectroscopic methods (NMR, IR, UV/vis), and the molecular structures of 3 and 4 were determined.