SILVER OLEFIN COMPLEXES IN THE CONDENSED PHASE

As mentioned in the introduction, r-bonded Ag-olefin complexes are paradigms in the thermochemistry of organometaUic species. Nonetheless, there are comparatively few relevant quantitative data. 

Experimental information on the energetics of silver-olefin bonds comes from a 1973 study by Partenheimer and Johnson . Using titration calorimetry with the inert dichloromethane as solvent, these authors measured the enthalpies of reaction 14 for several olefin complexes (hfacac = 1,1,1, 5, 5, 5-hexafluoro-2,4-pentanedionate) whose structure (1) is illustrated below for olefin = cyclohexene. 

Ag(hfacac)(olefin)(sln) PPhsfsln)------- Ag(hfacac)(PPh3)(sln) -I- olefin(sln) (14) 

The data, collected in Table 4, show the trend in Ag-olefin bond dissociation enthalpies in solution, the weakest bond being between Ag+ and cyclopentene and the strongest between Ag and cyclooctene. 

Joel F. Liebman, Jos6 Martinho Simoes and Suzanne W. Slayden 

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