Relative Kinetic Basicities of Organogold Compounds

The relative kinetic basicities of a series of differentially substituted and hybridized neutral organogold compounds were examined through competitive protodeauration experiments and were found to span 2.2 orders of magnitude. The effect of electron-withdrawing and electron-donating substituents on the rate of protodeauration of alkenylgold and arylgold compounds was explored. An acid counterion effect indicated the presence of a gold-mediated substrate preequilibrium before protodemetalation, and hybridization effects and a Hammett correlation with rho(+) = -0.41 indicated the involvement of the C-C pi system in the protodeauration of vinylgold, alkynylgold, and arylgold complexes.