The Acidity of Weak NH Acids: Expanding the pK a Scale in Acetonitrile.

IF 3.3 Q2 CHEMISTRY, MULTIDISCIPLINARY
ACS Organic & Inorganic Au Pub Date : 2025-03-13 eCollection Date: 2025-04-02 DOI:10.1021/acsorginorgau.4c00095
Märt Lõkov, Carmen Kesküla, Sofja Tshepelevitsh, Marta-Lisette Pikma, Jaan Saame, Dmitri Trubitsõn, Tõnis Kanger, Ivo Leito
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引用次数: 0

Abstract

Nitrogen heterocycles and aromatic amines are well-known and widely used compounds that are usually not seen as acids, although in organic solvents like acetonitrile (MeCN) or dimethyl sulfoxide (DMSO) their acidic properties can be observed. In this work, the acidities (pK a values) of 37 such weak NH acids were determined in acetonitrile and presented together with computational gas-phase acidities and literature pK a values in DMSO. In the course of the work the weakest acids range (from pK a 29 upward) of the MeCN acidity scale has been revised and expanded to around 33.5 by adding 31 compounds in that specific region and the span of experimental pK a values in MeCN is now more than 30 orders of magnitude. The relations between the structure and acidity of a selection of the studied compounds have been investigated in MeCN and DMSO. The measured pK a values in MeCN and the gathered pK a values in DMSO were used for a correlation analysis between the two solvents and for assessing the quality of pK a conversion equations. A number of pK a values have been predicted in MeCN from pK a values in DMSO via the correlation analysis and pK a conversion equations.

弱 NH 酸的酸度:扩大乙腈中的 pK a 范围。
氮杂环和芳香胺是众所周知和广泛使用的化合物,通常不被视为酸,尽管在有机溶剂中,如乙腈(MeCN)或二甲基亚砜(DMSO)可以观察到它们的酸性。在这项工作中,测定了37种弱NH酸在乙腈中的酸度(pK a值),并给出了DMSO中计算气相酸度和文献pK a值。在工作过程中,通过在特定区域添加31种化合物,对MeCN酸度标度的最弱酸范围(pK a 29以上)进行了修订,扩大到33.5左右,MeCN中实验pK a值的跨度现在超过30个数量级。在MeCN和DMSO中研究了所选化合物的结构和酸度之间的关系。将MeCN中测定的pK a值和DMSO中收集的pK a值用于两种溶剂之间的相关性分析,并评估pK a转换方程的质量。通过相关分析和pK A转换方程,从DMSO中的pK A值预测了MeCN中的多个pK A值。
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来源期刊
ACS Organic & Inorganic Au
ACS Organic & Inorganic Au 有机化学、无机化学-
CiteScore
4.10
自引率
0.00%
发文量
0
期刊介绍: ACS Organic & Inorganic Au is an open access journal that publishes original experimental and theoretical/computational studies on organic organometallic inorganic crystal growth and engineering and organic process chemistry. Short letters comprehensive articles reviews and perspectives are welcome on topics that include:Organic chemistry Organometallic chemistry Inorganic Chemistry and Organic Process Chemistry.
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