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Article: Experimental validation of Gaussian-3 lithium cation affinities of amides: Implications for the gas-phase lithium cation basicity scale

TitleExperimental validation of Gaussian-3 lithium cation affinities of amides: Implications for the gas-phase lithium cation basicity scale
Authors
Issue Date2002
PublisherJohn Wiley & Sons Ltd. The Journal's web site is located at http://www.interscience.wiley.com/jpages/0951-4198/
Citation
Rapid Communications In Mass Spectrometry, 2002, v. 16 n. 3, p. 229-237 How to Cite?
AbstractUsing a refined Gaussian-3 (G3) protocol, the highest level of ab initio calculations reported so far, we have established the Li+ cation binding enthalpy (affinity) at 0 K (in kJ mol-1) for formamide (195.7), N-methylformamide (209.2), N,N′-dimethylformamide (220.0), acetamide (211.7), N-methyl-acetamide (222.5), and N,N′-dimethylacetamide (230.1), with an estimated maximum uncertainty of ±8 kJ mol-1. With these six theoretical lithium cation binding affinities as reference values, the absolute Li+ affinities of imidazole and dimethoxyethane were determined by the extended kinetic method, and by adopting the statistical data treatment protocol recently proposed by Armentrout. The Li+ affinities obtained for these two ligands are in good agreement (within 6 kJ mol-1) with recent values determined by the threshold collision-induced dissociation method, and consistent with the Li+ basicity values first reported by Taft and co-workers in 1990. Our study confirms that the previously suggested, and recently implemented, downward revision of Taft's original basicity scale by 10.9 kJ mol-1 is justified for ligands with revised basicities less than 151 kJ mol-1. However, for selected ligands with Li+ basicities greater than 151 kJ mol-1, including some of the six amides studied in this work, the reported discrepancy between theoretical and experimental estimates in the revised Li+ basicity scale of Burk et al. is likely to arise from experimental uncertainties. Copyright © 2002 John Wiley & Sons, Ltd.
Persistent Identifierhttp://hdl.handle.net/10722/167724
ISSN
2015 Impact Factor: 2.226
2015 SCImago Journal Rankings: 0.819
ISI Accession Number ID
References

 

DC FieldValueLanguage
dc.contributor.authorTsang, Yen_US
dc.contributor.authorSiu, FMen_US
dc.contributor.authorMa, NLen_US
dc.contributor.authorTsang, CWen_US
dc.date.accessioned2012-10-08T03:10:29Z-
dc.date.available2012-10-08T03:10:29Z-
dc.date.issued2002en_US
dc.identifier.citationRapid Communications In Mass Spectrometry, 2002, v. 16 n. 3, p. 229-237en_US
dc.identifier.issn0951-4198en_US
dc.identifier.urihttp://hdl.handle.net/10722/167724-
dc.description.abstractUsing a refined Gaussian-3 (G3) protocol, the highest level of ab initio calculations reported so far, we have established the Li+ cation binding enthalpy (affinity) at 0 K (in kJ mol-1) for formamide (195.7), N-methylformamide (209.2), N,N′-dimethylformamide (220.0), acetamide (211.7), N-methyl-acetamide (222.5), and N,N′-dimethylacetamide (230.1), with an estimated maximum uncertainty of ±8 kJ mol-1. With these six theoretical lithium cation binding affinities as reference values, the absolute Li+ affinities of imidazole and dimethoxyethane were determined by the extended kinetic method, and by adopting the statistical data treatment protocol recently proposed by Armentrout. The Li+ affinities obtained for these two ligands are in good agreement (within 6 kJ mol-1) with recent values determined by the threshold collision-induced dissociation method, and consistent with the Li+ basicity values first reported by Taft and co-workers in 1990. Our study confirms that the previously suggested, and recently implemented, downward revision of Taft's original basicity scale by 10.9 kJ mol-1 is justified for ligands with revised basicities less than 151 kJ mol-1. However, for selected ligands with Li+ basicities greater than 151 kJ mol-1, including some of the six amides studied in this work, the reported discrepancy between theoretical and experimental estimates in the revised Li+ basicity scale of Burk et al. is likely to arise from experimental uncertainties. Copyright © 2002 John Wiley & Sons, Ltd.en_US
dc.languageengen_US
dc.publisherJohn Wiley & Sons Ltd. The Journal's web site is located at http://www.interscience.wiley.com/jpages/0951-4198/en_US
dc.relation.ispartofRapid Communications in Mass Spectrometryen_US
dc.subject.meshAlgorithmsen_US
dc.subject.meshAmides - Chemistryen_US
dc.subject.meshHydrogen-Ion Concentrationen_US
dc.subject.meshIonsen_US
dc.subject.meshKineticsen_US
dc.subject.meshLigandsen_US
dc.subject.meshLithium - Chemistryen_US
dc.subject.meshMass Spectrometryen_US
dc.subject.meshThermodynamicsen_US
dc.titleExperimental validation of Gaussian-3 lithium cation affinities of amides: Implications for the gas-phase lithium cation basicity scaleen_US
dc.typeArticleen_US
dc.identifier.emailSiu, FM:fmsiu@hku.hken_US
dc.identifier.authoritySiu, FM=rp00776en_US
dc.description.naturelink_to_subscribed_fulltexten_US
dc.identifier.doi10.1002/rcm.570en_US
dc.identifier.pmid11803545-
dc.identifier.scopuseid_2-s2.0-0036007820en_US
dc.relation.referenceshttp://www.scopus.com/mlt/select.url?eid=2-s2.0-0036007820&selection=ref&src=s&origin=recordpageen_US
dc.identifier.volume16en_US
dc.identifier.issue3en_US
dc.identifier.spage229en_US
dc.identifier.epage237en_US
dc.identifier.isiWOS:000173654300011-
dc.publisher.placeUnited Kingdomen_US
dc.identifier.scopusauthoridTsang, Y=7007101142en_US
dc.identifier.scopusauthoridSiu, FM=6701518489en_US
dc.identifier.scopusauthoridMa, NL=7103357185en_US
dc.identifier.scopusauthoridTsang, CW=7202935952en_US

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