Wiley InterScience Backfile Collection 1832-2000
Chemistry and Pharmacology
Studies on C—H Activation, X. - Synthesis of Alkyl(carbonyl)hydrido- and Allylhydridoosmium Complexes by Metal-initiated Fragmentation of Primary Alcohols and OlefinsHerrn Professor Dr. E. Lindner zum 60. Geburtstag gewidmet.The reaction of [(Mes)OsCl2]n (1) with RCH2OH/NaOH in the presence of propene leads to complete fragmentation of the primary alcohol and formation of the alkyl(carbonyl)hydrido complexes [(Mes)OsH(R)(CO)] (2-7). The corresponding chloro derivatives [(Mes)OsC1(R)(CO)] (8-13) are obtained either by H/C1 exchange from 2-7 and CC14 or on treatment of [(Mes)OsR2(CO)] (16-21) with HC1 at -78°C. The carbonylosmium(II) compound [(Mes)Os(CO)C12] (15) reacts with iC4H9MgI to give a mixture of [(Mes)Os(iC4H9)2(CO)] (21), [(Mes)OsI(iC4H9)(CO)] (22), and [(Mes)Os(CO)I2] (23), whereas the reaction of 15 with C6H11CH2MgBr yields [(Mes)Os(CH2C6H11)2(CO)] (24), the olefin complex [(Mes)Os(CH2=C6H10)(CO)] (25), and [(Mes)OsH(Br)(CO)] (26). The alkylhydridoosmium(II) compound [(Mes)OsH(CH2C6H11)(CO)] (28) is obtained from the chloro derivative 27 and Mg/Hg/C2H5OH. Treatment of 1 with iC3H7OH/NaOH and propene or isobutene affords the η3-allylhydrido complexes [(Mes)OsH(η3-2-RC3H4)] (31, 32) in about 85% yield, while the reaction of 1 with iC3H7OH/NaOH and tert-butylethene gives [(Mes)Os(CH2=CHtC4H9)2] (35). The X-ray structural analysis of [(Mes)OsH(η3-2-CH3C3H4)] (34), which like the corresponding η3-allylchloro compound 33 is formed from the η3-allylhydrido complex 31 or 32 and CC14, reveals a half sandwich-type structure with an exo arrangement of the methallyl ligand.
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