Please use this identifier to cite or link to this item:
https://hdl.handle.net/10316/10718
DC Field | Value | Language |
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dc.contributor.author | Jarmelo, Susana | - |
dc.contributor.author | Maria, Teresa M. R. | - |
dc.contributor.author | Leitão, Maria Luísa P. | - |
dc.contributor.author | Fausto, Rui | - |
dc.date.accessioned | 2009-07-17T09:32:30Z | - |
dc.date.available | 2009-07-17T09:32:30Z | - |
dc.date.issued | 2001-01-15 | - |
dc.identifier.citation | Physical Chemistry Chemical Physics. 3 (2001) 387-392 | en_US |
dc.identifier.issn | 1463-9076 | - |
dc.identifier.uri | https://hdl.handle.net/10316/10718 | - |
dc.description.abstract | The 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.sponsorship | Fundação para a Ciência e Tecnologia, programas PRAXIS QUI/10137/98 e SFRH/157/2000. | en_US |
dc.language.iso | eng | en_US |
dc.publisher | Royal Society of Chemistry | en_US |
dc.rights | openAccess | eng |
dc.title | The low temperature crystalline and glassy states of methyl -hydroxy-isobutyrate | en_US |
dc.type | article | en_US |
dc.identifier.doi | 10.1039/b007722o | - |
uc.controloAutoridade | Sim | - |
item.fulltext | Com Texto completo | - |
item.grantfulltext | open | - |
item.languageiso639-1 | en | - |
item.cerifentitytype | Publications | - |
item.openairetype | article | - |
item.openairecristype | http://purl.org/coar/resource_type/c_18cf | - |
crisitem.author.dept | Universidade de Coimbra | - |
crisitem.author.parentdept | Institute of Interdisciplinary Research | - |
crisitem.author.researchunit | CQC - Coimbra Chemistry Centre | - |
crisitem.author.researchunit | CQC - Coimbra Chemistry Centre | - |
crisitem.author.parentresearchunit | Faculty of Sciences and Technology | - |
crisitem.author.parentresearchunit | Faculty of Sciences and Technology | - |
crisitem.author.orcid | 0000-0001-5771-458X | - |
crisitem.author.orcid | 0000-0002-7143-2228 | - |
crisitem.author.orcid | 0000-0002-8264-6854 | - |
Appears in Collections: | FCTUC Química - Artigos em Revistas Internacionais |
Files in This Item:
File | Description | Size | Format | |
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The low temperature crystalline.pdf | 175.24 kB | Adobe PDF | View/Open |
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