Please use this identifier to cite or link to this item: http://hdl.handle.net/10316/10718
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dc.contributor.authorJarmelo, Susana-
dc.contributor.authorMaria, Teresa M. R.-
dc.contributor.authorLeitão, Maria Luísa P.-
dc.contributor.authorFausto, Rui-
dc.date.accessioned2009-07-17T09:32:30Z-
dc.date.available2009-07-17T09:32:30Z-
dc.date.issued2001-01-15-
dc.identifier.citationPhysical Chemistry Chemical Physics. 3 (2001) 387-392en_US
dc.identifier.issn1463-9076-
dc.identifier.urihttp://hdl.handle.net/10316/10718-
dc.description.abstractThe low temperature crystalline and glassy phases of methyl -hydroxy-isobutyrate (MHib) were identified and characterized structurally by differential scanning calorimetry, IR and Raman spectroscopy and molecular modeling. Within the temperature range 13–171 K, MHib exists as a glassy state, where individual molecules may assume the two conformational states previously observed for this compound isolated in an argon matrix and in the liquid phase [S. Jarmelo and R. Fausto, J. Mol. Struct., 1999, 509, 193]. At ca. 171 K, devitrification occurs and a crystalline phase may then be formed [T(onset)213 K], the enthalpy of crystallization being ca. 5 kJ mol–1. The crystalline phase was found to exhibit conformational selectivity—in this phase all individual molecules assume a conformation analogous to the most stable conformer found for the isolated molecule and in the liquid (the Syn-syn s-cis conformer, where the H–O–C–C, O–C–CO and OC–O–C dihedrals are ca. 0°). Molecular modeling and Raman data are consistent with a structural unit within the crystal where two MHib molecules form a centrosymmetrical hydrogen bonded dimer. The observed temperature of fusion [Tf(peak)] for the crystal is 240 K.en_US
dc.description.sponsorshipFundação para a Ciência e Tecnologia, programas PRAXIS QUI/10137/98 e SFRH/157/2000.en_US
dc.language.isoengen_US
dc.publisherRoyal Society of Chemistryen_US
dc.rightsopenAccesseng
dc.titleThe low temperature crystalline and glassy states of methyl -hydroxy-isobutyrateen_US
dc.typearticleen_US
dc.identifier.doi10.1039/b007722o-
item.fulltextCom Texto completo-
item.grantfulltextopen-
item.languageiso639-1en-
crisitem.author.deptFaculdade de Ciências e Tecnologia, Universidade de Coimbra-
crisitem.author.parentdeptUniversidade de Coimbra-
crisitem.author.researchunitCoimbra Chemistry Center-
crisitem.author.orcid0000-0002-8264-6854-
Appears in Collections:FCTUC Química - Artigos em Revistas Internacionais
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