Ab initio modeling of organolithium equilibria.

Experimental ion pair pK's of monomeric contact ion pair lithium salts in THF from our previous studies give good correlations with ab initio calculations at the Hartree-Fock 6-31+g(d) level. PCM methods were found to be inadequate in nonpolar organic solvents, and dielectric solvation was not used in the correlations. Specific coordination of two or three ether solvent molecules with lithium was found to be satisfactory. These correlations include carboxamides, amines, dithianes, sulfones, and sulfoxides, as well as some ketones, beta-diketones, and the lithium salts of dianions.