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...

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Bibliographic Details
Published in:Journal of organic chemistry 2012-01, Vol.77 (2), p.985-990
Main Authors: Streitwieser, Andrew, Facchetti, Antonio, Xie, Linfeng, Zhang, Xingyue, Wu, Eric C
Format: Article
Language:English
Subjects:
Chemistry
Exact sciences and technology
Kinetics and mechanisms
Organic chemistry
Reactivity and mechanisms
Online Access:Get full text
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Summary: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.
ISSN:0022-3263
1520-6904
DOI:10.1021/jo202253q