Publication
Equilibrium constants and protonation site for N-methylbenzenesulfonamides
| dc.contributor.author | Moreira, José | |
| dc.contributor.author | Costa, Ana M. Rosa da | |
| dc.contributor.author | García-Río, Luís | |
| dc.contributor.author | Pessêgo, Márcia | |
| dc.date.accessioned | 2013-12-09T17:02:56Z | |
| dc.date.available | 2013-12-09T17:02:56Z | |
| dc.date.issued | 2011 | |
| dc.date.updated | 2013-12-04T18:06:35Z | |
| dc.description.abstract | The protonation equilibria of four substituted N-methylbenzenesulfonamides, X-MBS: X = 4-MeO (3a), 4-Me (3b), 4-Cl (3c) and 4-NO2 (3d), in aqueous sulfuric acid were studied at 25 °C by UV–vis spectroscopy. As expected, the values for the acidity constants are highly dependent on the electron-donor character of the substituent (the pKBH+ values are −3.5 ± 0.2, −4.2 ± 0.2, −5.2 ± 0.3 and −6.0 ± 0.3 for 3a, 3b, 3c and 3d, respectively). The solvation parameter m* is always higher than 0.5 and points to a decrease in the importance of solvation on the cation stabilization as the electron-donor character of the substituent increases. Hammett plots of the equilibrium constants showed a better correlation with the σ+ substituent parameter than with σ, which indicates that the initial protonation site is the oxygen atom of the sulfonyl group. | por |
| dc.identifier.citation | Moreira, José A.; Rosa da Costa, Ana M.; García-Río, Luís; Pessêgo, Márcia. Equilibrium constants and protonation site for N -methylbenzenesulfonamides, Beilstein Journal of Organic Chemistry, 7, 1732-1738, 2011. | por |
| dc.identifier.doi | http://dx.doi.org/doi:10.3762/bjoc.7.203 | |
| dc.identifier.issn | 1860-5397 | |
| dc.identifier.other | AUT: AMC01695; JMO01545; | |
| dc.identifier.uri | http://hdl.handle.net/10400.1/3233 | |
| dc.language.iso | eng | por |
| dc.peerreviewed | yes | por |
| dc.publisher | Beilstein-Institut | por |
| dc.relation | Structure-reactivity relationships on nitroso group transfer to nucleophiles | |
| dc.relation.publisherversion | http://www.beilstein-journals.org/bjoc/single/articleFullText.htm?publicId=1860-5397-7-203 | por |
| dc.subject | Linear free-energy relationships | por |
| dc.subject | N-methylbenzenesulfonamides | por |
| dc.subject | Protonation equilibrium | por |
| dc.title | Equilibrium constants and protonation site for N-methylbenzenesulfonamides | por |
| dc.type | journal article | |
| dspace.entity.type | Publication | |
| oaire.awardTitle | Structure-reactivity relationships on nitroso group transfer to nucleophiles | |
| oaire.awardURI | info:eu-repo/grantAgreement/FCT/POCI/POCI%2FQUI%2F57077%2F2004/PT | |
| oaire.citation.endPage | 1738 | por |
| oaire.citation.startPage | 1732 | por |
| oaire.citation.title | Beilstein Journal of Organic Chemistry | por |
| oaire.citation.volume | 7 | por |
| oaire.fundingStream | POCI | |
| person.familyName | Moreira | |
| person.familyName | Rosa da Costa | |
| person.givenName | José | |
| person.givenName | Ana M | |
| person.identifier | 305029 | |
| person.identifier.ciencia-id | DC11-4E1F-F13F | |
| person.identifier.ciencia-id | A418-A85E-5DB1 | |
| person.identifier.orcid | 0000-0001-8481-3436 | |
| person.identifier.orcid | 0000-0003-0225-9537 | |
| person.identifier.rid | F-3807-2010 | |
| person.identifier.rid | E-2165-2012 | |
| person.identifier.scopus-author-id | 7201506886 | |
| person.identifier.scopus-author-id | 53986075100 | |
| project.funder.identifier | http://doi.org/10.13039/501100001871 | |
| project.funder.name | Fundação para a Ciência e a Tecnologia | |
| rcaap.rights | openAccess | por |
| rcaap.type | article | por |
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