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The infrared spectrum of solid L-alanine: influence of pH-induced structural changes

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dc.contributor.authorGarcia, Ana
dc.contributor.authorBarros, R. B. de
dc.contributor.authorLourenço, J. P.
dc.contributor.authorIlharco, Laura M.
dc.date.accessioned2013-01-07T14:28:28Z
dc.date.available2013-01-07T14:28:28Z
dc.date.issued2008
dc.date.updated2013-01-03T10:30:37Z
dc.description.abstractThe influence of the pH on the infrared spectrum of L-alanine has been analyzed by diffuse reflectance infrared Fourier transform (DRIFT) spectroscopy. The amino acid was precipitated from aqueous solutions and dried at 36.5 °C, in order to stabilize cationic L-alanine or alaninium [CH3CH(NH3 +)COOH] at pH 1, the zwitterionic form [CH3CH(NH3 +)COO-] at pH 6, and anionic L-alanine or alaninate [CH3CH(NH2)COO-] at pH 13. New insight on the specific inter and intramolecular interactions in the different forms of L-alanine was reached by a novel methodological approach: an infrared technique not used before to analyze solid amino acid samples (DRIFTS), in combination with a detailed analysis based on spectral deconvolution. The frequency ranges of interest include the carbonyl/carboxyl stretching and amine deformation modes and the OH/NH stretching modes. It was shown that intermolecular hydrogen bonds between the NH3 + and COO- groups are predominant in the zwitterionic form, whereas in cationic L-alanine, H bonds between the COOH groups are responsible for the formation of dimers. In anionic L-alanine, only strong electrostatic interactions between the COOgroups and Na+ ions are proposed, evidencing the relevant role of the counterion.por
dc.identifier.citationGarcia, A. R.; de Barros, R. B.; Lourenço, J. P.; Ilharco, L. The infrared spectrum of solid L-alanine: influence of pH-induced structural changes, J. Phys. Chem. A, 112, 8280-8287, 2008.por
dc.identifier.issn1089-5639
dc.identifier.otherAUT: ARG01643; JLO01215;
dc.identifier.urihttp://hdl.handle.net/10400.1/2060
dc.language.isoengpor
dc.peerreviewedyespor
dc.publisherAmerican Chemical Societypor
dc.subjectL-alaninepor
dc.subjectStructural changespor
dc.subjectFTIRpor
dc.titleThe infrared spectrum of solid L-alanine: influence of pH-induced structural changespor
dc.typejournal article
dspace.entity.typePublication
oaire.citation.endPage8287por
oaire.citation.startPage8280por
oaire.citation.titleJournal of Physical Chemistry Apor
oaire.citation.volume112por
person.familyNameGarcia
person.familyNameLourenço
person.givenNameAna
person.givenNameJoão P.
person.identifier634248
person.identifier.ciencia-idB214-EA2D-350A
person.identifier.ciencia-idF81F-A1F0-2A7C
person.identifier.orcid0000-0001-6289-4554
person.identifier.orcid0000-0002-0501-6672
person.identifier.ridA-7758-2008
person.identifier.scopus-author-id7404608764
person.identifier.scopus-author-id57195730600
rcaap.rightsrestrictedAccesspor
rcaap.typearticlepor
relation.isAuthorOfPublicatione49828e5-432e-46e3-a7fc-2fdbf51a237b
relation.isAuthorOfPublicationf66ab886-d989-4c1d-9550-527507723c26
relation.isAuthorOfPublication.latestForDiscoverye49828e5-432e-46e3-a7fc-2fdbf51a237b

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