918149-49-2Relevant academic research and scientific papers
Preparation and characterization of novel Os-diolefin dimers: New entry to Os-cyclooctadiene complexes
Esteruelas, Miguel A.,Garcia-Yebra, Cristina,Olivan, Montserrat,Onate, Enrique
, p. 10162 - 10171 (2006)
The complex [H(EtOH)2][{OsCl(η4-COD)} 2(μ-H)(μ-Cl)2] (1) has been prepared in high yield by treatment of OsCl3· 3H2O (54% Os) with 1,5-cyclooctadiene in ethanol under reflux. Under air, it is unstable and undergoes oxidation by action of O2 to afford the neutral derivative {OsCl(η4-COD)}2(μ-H)(μ-Cl)2 (2). The terminal chlorine ligands of the anion of 1 are activated toward nucleophilic substitution. Thus, reaction of the salt [NBu4] [{OsCl(η4-COD)}2-(μ-H)(μ-Cl)2] (1a) with NaCp in toluene gives [NBu4][{Os(η1-C 5H5)(η4-COD)}(μ-H)(μ-Cl) 2{OsCl(η4-COD)}] (3) as a result of the replacement of one of the terminal chlorine atoms by the cyclopentadienyl ligand. The CH 2 group of the latter can be deprotonated by the bridging methoxy ligand of the iridium dimer [Ir(μ-OMe)(η4-COD)]2. The reaction leads to the trinuclear derivative [NBu4] [{(η4-COD)Ir(η5-C5H4- η1)Os(η4-COD)}(μ-H)(μ-Cl) 2{OsCl(η4-COD)}] (4) containing a bridging C 5H4 ligand that is η1-coordinated to an osmium atom of the dimeric unit and η5-coordinated to the Ir(η4-COD) moiety. Salt 1a also reacts with LiC≡CPh. In this case, the reaction produces the substitution of both terminal chlorine ligands to afford the bis(alkynyl) derivative [NBu4][{Os(C≡CPh) (η4-COD)}2(μ-H)(μ-Cl)2] (5). Complexes 1, 2, 3, and 4 have been characterized by X-ray diffraction analysis. Although the separations between the osmium atoms are short, between 2.6696(4) and 2.8633(5) A, theoretical calculations indicate that only in 2 is there direct metal-metal interaction, as the bond order is 0.5.
