Ion pair pKs of some amines: extension of the computed lithium pK scale.
The pK of p-(methylamino)biphenyl, 1, on our Li scale, pK(Li) = 22.09, compared to the cesium scale, pK(Cs) = 28.60. For hexamethyldisilazane, HMDS, pK(Li) = 23.05, pK(Cs) = 29.26. These results are those for the monomers in THF; corrections were made for dimers present in some cases. The pK(Li) of these two amines fit well the previously found correlation with Hartree-Fock calculations at 6-31+g(d) using RLi coordinated with three dimethyl ethers as a computational model for RLi in THF. The results are also compared with earlier pK(Li)s reported from equilibria with lithium amides in which aggregation was not considered.
Department of Chemistry, University of California-Berkeley, Berkeley, California 94720-1460, USA. astreit@berkeley.edu
Andrew
A
Streitwieser
Antonio
A
Facchetti
Linfeng
L
Xie
Xingyue
X
Zhang
Eric C
EC
Wu