Cycloocta-1,5-diene complexes ruthenium

In addition to the design of the solubility properties, the reactivity of organome-tallic species toward CO2 [13] (and many other potential supercritical reaction media) must be considered as important criteria for the choice of the catalyst. For example, the bisallyl ruthenium complex shown in Table 1 cannot be utilized as a precursor for ring-opening metathesis polymerization (ROMP) in SCCO2, because the insertion of CO2 into the Ru-allyl bond prevents the initiation mechanism [14]. Metal-mediated oxygen transfer to form CO and phosphine oxide was found to lead to deactivation of the [Ni(cod)2]/PMe3 (cod = 1,5-m-cycloocta-diene) catalyst system [15]. On the other hand, the reactivity of CO2 with metal... 

The ( /4-bicyclo[2.2.1]hepta-2,5-diene)bis( /3-2-propenyl)ruthenium(II) and (>/4-cycloocta-l,5-diene)bis(>/3-2-propenyl)ruthenium(II) complexes have previously been reported,5,6 but we present here scaled-up procedures that produce synthetically useful quantities of these compounds. The preparation of Grignard reagents is based upon the methods described by Eisch.7... 

The complexes ( /4-cycloocta-l, 5-diene)bis(>/3-2-methyl-l-propenyl)-ruthenium(II), [ Ru(i/4-C8H12)(02CCCl3) 2(p-02CCCl3)2(/i-0H2)], and [ Ru( 4-C7H8)(02CCF3) 2(p-02CCCl3)2(p-0H2)] may be prepared by procedures similar to those described for the related complexes in Sections D, E, and G. 

Polymeric-ruthenium catalysts have been prepared by the reaction of ( / -cyclo-octa-l,3,5-triene) (// -cycloocta-1,5-diene) ruthenium(0), (// -cydoocta-l,3,5-triene) (COT) (// -cycloocta-1,5-diene) (COD) with polystyrene in hydrogen at room temperature [258]. Elemental analysis, IR and mass-spectrometry data show that in these polymer-metal complexes, two cycloolefin ligands, present in the starting Ru(COT)(COD) complex, are substituted by two phenyl rings of polystyrene ... 

II, D), is much more air-sensitive than the yellow ruthenium compound. A colorless osmium(O) analog could not be isolated in a pure state. It is interesting that the same complexes are formed, albeit in lower yields, by starting with cycloocta-l,5-diene only. Evidently the intermediate alkyl iron compounds readily abstract hydrogen from the diene. 

The complex functions as the most suitable source of the tricarbonylruth-enium unit in syntheses of tiicarbonyl(i -diene)ruthenium complexes. Derivatives of 1,3-cyclohexadiene, 1,3-cycloheptadiene, cycloheptatriene, cycloocta-tetraene, 2,4,6-cycloheptatrien-l-one, bicyclo[3.2.1]octa-2,6-diene, bicyclo-[3.2.1]octa-2,4-diene, and butadiene have been prepared by displacement of 1,5-cyclooctadiene. 

Abstract A l,3-bis-(2,6-diisopropylphenyl)-4,5-dihydroiiradazol-2-ylidene substituted ruthenium (Ru)-based complex (4) has been prepared starting from (PCysHClERuK HPh (2). The catalytic performance of catalyst (4) is checked on ring-opening metathesis polymerization (ROMP) of the low strain monomer, cycloocta-1,5-diene (COD), and also compared with catalyst (2) and (3). 

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