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The in situ synthesis of supported ruthenium carbonylsBergmeister, Joseph John January 1989 (has links)
The compound Ru⁺²(CO)₃Cl₂(THF) spontaneously adsorbs onto MgO, Al₂O₃, SiO₂, and NaY zeolite from THF solution evolving less than 0.1 equivalent of CO to yield a light yellow supported complex. Based on reaction stoichiometry, CO evolution and in situ infrared spectroscopy, the adsorption was found to produce two different surface-bound species depending on the support used. On SiO₂ and NaY zeolite, the surface species Ru⁺²(CO)₃Cl₂(SURFACE) is formed by a ligand substitution of THF for a surface hydroxyl group. When the adsorption is performed on MgO or AI₂O₃, the inorganic oxide acts as a chloride acceptor to form the surface species Ru⁺²(CO)₃(SURFACE)₃.
A molecular analog of the adsorbed species Ru(CO)₃Cl₂(SURFACE) was synthesized and characterized by infrared spectroscopy, ¹H NMR, and an X-ray crystal structure. The infrared spectra of the adsorbed species, Ru(CO)₃Cl₂(SURFACE), and the model compound were in close agreement. Model compounds of Ru(CO)₃(SURFACE)₃ were also synthesized: however, these could not be structurally characterized.
The reactivity of the adsorbed species, Ru(CO)₃Cl₂(SURFACE) and Ru(CO)₃(SURFACE)₃, towards the formation of supported bimetallics, polynuclear ruthenium carbonyl clusters, and ruthenium bipyridine coordination compounds was investigated. On SiO₂ and NaY zeolite, the chemistry of Ru(CO)₃Cl₂(SURFACE) paralleled that of Ru(CO)₃Cl₂(THF) in solution. On Al₂O₃ and MgO, the chemistry of Ru(CO)₃(SURFACE), was indicative of an adsorbed ruthenium carbonyl-containing no chloride ligands.
The bimetallic cluster RuCo₃(CO)₁₂⁻ was synthesized on hydroxylated Al₂O₃ by the disproportionation of RuCo₂(CO)₁₁. The trimeric cluster RuCo₂(CO)₁₁ is spontaneously adsorbed onto AI₂O₃ from a pentane solution yielding the adsorbed species "RuCo₂(CO)₁₀", this was then transformed to the tetrameric cluster RuCo₃(CO)₁₂⁻ by the addition of THF. The adsorbed cluster anion RuCo₃(CO)₁₂⁻ could also be synthesized on AI₂O₃ by the deprotonation of the hydridic cluster HRuCo₃(CO)₁₂. Depending on the route, infrared evidence suggests formation of a solvated or unsolvated anion on the surface. / Ph. D.
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