Inductive vs Solvation Effects in Primary Alkyl Amines: Determination of the Standard Potentials
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- 作者：José ; Luis Bourdelande ; Iluminada Gallardo ; Gonzalo Guirado
- 刊名：Journal of the American Chemical Society
- 出版年：2007
- 出版时间：March 14, 2007
- 年：2007
- 卷：129
- 期：10
- 页码：2817 - 2821
- 全文大小：154K
- 年卷期：v.129,no.10(March 14, 2007)
- ISSN：1520-5126
文摘
The determination of the standard potential of alkyl primary amines is reported for the first timeusing the nanosecond equilibrium method. The versatility and accuracy of the method demonstrates thatit is not only an alternative to the classical and modern electrochemical methods, but also a powerful toolfor quantifying inductive and/or solvation effects in a related family of compounds. Two different trendswere observed depending on alkyl chain length. For "short-chain" alkyl primary amines, where the solvationaround the amino group is expected to be the same, the standard potential value appears to follow a linearrelationship with the number of carbon atoms, which indicates that the methylene group (-CH2-) causesan inductive effect that is responsible for the stabilization of the amine cation radical. Meanwhile, the E
rises slightly to a constant potential value 1.500 V for "long-chain" unbranched alkyl primary amines. Thisinteresting result can be explained by a steric inhibition of solvation around the amino group due to a foldof the long alkyl chain following a solvent exclusion mechanism.
rises slightly to a constant potential value 1.500 V for "long-chain" unbranched alkyl primary amines. Thisinteresting result can be explained by a steric inhibition of solvation around the amino group due to a foldof the long alkyl chain following a solvent exclusion mechanism.