| Experimental and computational study on the molecular energetics of 2-pyrrolecarboxylic acid and 1-methyl-2-pyrrolecarboxylic acid. | |
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MedLine Citation:
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PMID: 19670901 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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This paper reports a combined thermochemical experimental and computational study of 2-pyrrolecarboxylic acid and 1-methyl-2-pyrrolecarboxylic acid. Static bomb combustion calorimetry and Knudsen mass-loss effusion technique were used to determine the standard (p degrees = 0.1 MPa) molar enthalpies of combustion, Delta(c)H(m) degrees, and sublimation, Delta(cr)(g)H(m) degrees, respectively, from which the standard (p degrees = 0.1 MPa) molar enthalpies of formation, in the gaseous phase, at T = 298.15 K, were derived. The values obtained were -(286.3 +/- 1.7) and -(291.6 +/- 1.7) kJ x mol for 2-pyrrolecarboxylic acid and 1-methyl-2-pyrrolecarboxylic acid, respectively. For comparison purposes, the gas-phase enthalpies of formation of these two compounds were estimated by G3(MP2)//B3LYP and MP2 approaches, using a set of gas-phase working reactions; the results are in excellent agreement with experimental data. G3(MP2)//B3LYP computations were also extended to the calculation of N-H bond dissociation enthalpies, gas-phase acidities and basicities, proton and electron affinities and adiabatic ionization enthalpies. Moreover, the results are also discussed in terms of the energetic effects of the addition of a carboxylic and of a methyl groups to the pyrrole ring and compared with structurally similar compounds. |
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Authors:
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Ana Filipa L O M Santos; Manuel A V Ribeiro da Silva |
Publication Detail:
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Type: Journal Article; Research Support, Non-U.S. Gov't |
Journal Detail:
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Title: The journal of physical chemistry. A Volume: 113 ISSN: 1520-5215 ISO Abbreviation: J Phys Chem A Publication Date: 2009 Sep |
Date Detail:
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Created Date: 2009-08-27 Completed Date: 2009-12-11 Revised Date: - |
Medline Journal Info:
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Nlm Unique ID: 9890903 Medline TA: J Phys Chem A Country: United States |
Other Details:
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Languages: eng Pagination: 9741-50 Citation Subset: IM |
Affiliation:
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Centro de Investigação em Química, Department of Chemistry, Faculty of Science, University of Porto, Rua do Campo Alegre, 687, P-4169-007 Porto, Portugal. |
Export Citation:
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| MeSH Terms | |
Descriptor/Qualifier:
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Calorimetry Carboxylic Acids / chemistry* Computer Simulation Gases / chemistry Models, Molecular* Molecular Conformation Phase Transition Proline / analogs & derivatives*, chemistry Pyrroles / chemistry* Thermodynamics |
| Chemical | |
Reg. No./Substance:
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0/1-methyl-2-pyrrolecarboxylic acid; 0/Carboxylic Acids; 0/Gases; 0/Pyrroles; 147-85-3/Proline; 634-97-9/2-pyrrolecarboxylic acid |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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