SILVER I OLEFIN COMPLEXES IN THE CONDENSED PHASE

As mentioned in the introduction, TT-bonded Ag-olefin complexes are paradigms in the thermochemistry of organometallic 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 Johnson26. 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) + PPh3(sln)---- Ag(hfacac)(PPh3)(sln) + 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, Jose Martinho Simoes and Suzanne W. Slayden 

---