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Title:Synthesis of Large Carbonyl Clusters of Ruthenium, Osmium and Rhenium
Author(s):Hayward, Chi-Mi Tai
Department / Program:Chemistry
Degree Granting Institution:University of Illinois at Urbana-Champaign
Subject(s):Chemistry, Inorganic
Abstract:The efficient preparation of several large anionic carbonyl clusters of ruthenium and osmium from M(,3)(CO)(,12) (M = Ru, Os) and sodium have been developed. Similar procedures have provided large anionic clusters of rhenium from Re(,2)(CO)(,10).
The reaction of Ru(,3)(CO)(,12) and sodium in a 1:1 mole ratio affords Ru(,6)(CO)(,18)('2-) in refluxing tetrahydrofuran (66(DEGREES)C) but Ru(,6)C(CO)(,16)('2-) in refluxing diglyme (162(DEGREES)C). Under the latter conditions Ru(,6)(CO)(,18)('2-) is converted quantitatively to Ru(,6)C(CO)(,16)('2-) with the evolution of carbon dioxide, which has been trapped as barium carbonate. Treatment of Os(,3)(CO)(,12) with sodium (Os:Na = 1:1) in diglyme (150-160(DEGREES)C) provides Os(,6)(CO)(,18)('2-). Pyrolysis of Os(,6)(CO)(,18)('2-) in triglyme (216(DEGREES)C) gives Os(,10)C(CO)(,24)('2-) as the major product, which is formed also from the direct reaction of Os(,3)(CO)(,12) with sodium in tetraglyme at 230-260(DEGREES)C. Oxidation of Ru(,6)C(CO)(,16)('2-) and Os(,6)(CO)(,18)('2-) with aqueous ferric chloride in a carbon monoxide atmosphere produces Ru(,6)C(CO)(,17) and Os(,6)(CO)(,18) in good yields. A compound formulated as Os(,6)C(CO)(,17) is isolated in low yield from the similar oxidation of reaction mixtures produced upon pyrolysis of Os(,6)(CO)(,18)('2-). This is suggested as evidence for the formation of Os(,6)C(CO)(,16)('2-) under the conditions for conversion of Os(,6)(CO)(,18)('2-) to Os(,10)C(CO)(,24)('2-). Extended pyrolysis of Ru(,6)C(CO)(,16)('2-) also provides a decanuclear cluster, but Ru(,10)C(,2)(CO)(,24)('2-) has two carbide ligands. The structural analysis of Ru(,10)C(,2)(CO)(,24)('2-) shows the metal framework to be used on two essentially octahedral moieties fused at a common equatorial edge.
Treatment of Re(,2)(CO)(,10) with sodium (Re(,2):Na = 1:1) in diglyme at 150(DEGREES)C affords Re(,4)(CO)(,16)('2-), which in refluxing diglyme (162(DEGREES)C) is converted predominantly to H(,2)Re(,6)C(CO)(,18)('2-). In the latter transformation Re(,7)C(CO)(,21)('3-) and Re(,8)C(CO)(,24)('2-) are obtained as minor products. These clusters have been prepared selectively by employing the appropriate stoichiometric ratio of Re(,2)(CO)(,10) and sodium (Re(,2):Na = 3.5:3 for Re(,7)C and 4:2 for Re(,8)C) in triglyme (190-210(DEGREES)C). In both syntheses Re(,4)(CO)(,16)('2-) and then H(,2)Re(,6)C(CO)(,18)('2-) are the intermediates observed prior to the formation of product.
Issue Date:1984
Description:138 p.
Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1984.
Other Identifier(s):(UMI)AAI8409777
Date Available in IDEALS:2014-12-15
Date Deposited:1984

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