{"title":"Polarisation effects on the H-bond acceptor properties of sulfonamides.","authors":"Fergal E Hanna, Christopher A Hunter","doi":"10.1039/d4cc03530e","DOIUrl":null,"url":null,"abstract":"<p><p>The strengths of H-bonding interactions in networks are affected by cooperativity between the interacting sites. Compounds with an intramolecular H-bond between a sulfonamide NH group and pyridine nitrogen were used to measure the magnitude of cooperative effects on intermolecular H-bonding interactions with the sulfonamide oxygen. X-ray crystallography and <sup>1</sup>H NMR experiments confirm the presence of the intramolecular H-bond and show that it is maintained in the 1 : 1 complex formed with perfluoro-<i>tert</i>-butanol (PFTB) in <i>n</i>-octane solution. Association constants for formation of 1 : 1 complexes with PFTB were determined using UV/Vis absorption titrations for a series of compounds equipped with different pyridine groups. Substituents on the pyridine were used to tune the strength of the intramolecular H-bond and investigate the effects on the strength of the intermolecular H-bond. Electron-donating groups on the pyridine that increase the strength of the intramolecular H-bond were found to increase in the strength of the intermolecular interaction with PFTB. The results were used to determine the H-bond acceptor parameters, <i>β</i>, for the sulfonamide oxygen group, and the values show a linear relationship with the value of <i>β</i> for the pyridine nitrogen. The slope of this relationship corresponds to the cooperativity parameter, <i>κ</i>, which is +0.16. The positive cooperativity observed in H-bonded sulfonamides is comparable to the value measured previously for the amide group (<i>κ</i> = +0.20).</p>","PeriodicalId":67,"journal":{"name":"Chemical Communications","volume":null,"pages":null},"PeriodicalIF":4.3000,"publicationDate":"2024-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Chemical Communications","FirstCategoryId":"92","ListUrlMain":"https://doi.org/10.1039/d4cc03530e","RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q2","JCRName":"CHEMISTRY, MULTIDISCIPLINARY","Score":null,"Total":0}
引用次数: 0
Abstract
The strengths of H-bonding interactions in networks are affected by cooperativity between the interacting sites. Compounds with an intramolecular H-bond between a sulfonamide NH group and pyridine nitrogen were used to measure the magnitude of cooperative effects on intermolecular H-bonding interactions with the sulfonamide oxygen. X-ray crystallography and 1H NMR experiments confirm the presence of the intramolecular H-bond and show that it is maintained in the 1 : 1 complex formed with perfluoro-tert-butanol (PFTB) in n-octane solution. Association constants for formation of 1 : 1 complexes with PFTB were determined using UV/Vis absorption titrations for a series of compounds equipped with different pyridine groups. Substituents on the pyridine were used to tune the strength of the intramolecular H-bond and investigate the effects on the strength of the intermolecular H-bond. Electron-donating groups on the pyridine that increase the strength of the intramolecular H-bond were found to increase in the strength of the intermolecular interaction with PFTB. The results were used to determine the H-bond acceptor parameters, β, for the sulfonamide oxygen group, and the values show a linear relationship with the value of β for the pyridine nitrogen. The slope of this relationship corresponds to the cooperativity parameter, κ, which is +0.16. The positive cooperativity observed in H-bonded sulfonamides is comparable to the value measured previously for the amide group (κ = +0.20).
期刊介绍:
ChemComm (Chemical Communications) is renowned as the fastest publisher of articles providing information on new avenues of research, drawn from all the world''s major areas of chemical research.