Estudo ab-initio da a-alanina em meio aquoso
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Data
1999-07-01
Autores
Sambrano, Julio Ricardo [UNESP]
Souza, Aguinaldo Robinson de [UNESP]
Queralt, Joaquim Josep
Andrés, Juan
Longo, Elson [UNESP]
Título da Revista
ISSN da Revista
Título de Volume
Editor
Sociedade Brasileira de Química
Resumo
Ab initio Hartree-Fock (HF), Density Functional (B3LYP) and electron correlation (MP2) methods have been used to caracterize the aqueous medium intramolecular hydrogen bond in a-alanine. The 6-31G* and 6-31++G** were taken from Gaussian94 library. We were concerned on the structure of three conformers of a-alanine, in their neutral form plus on the structure of the zwitterionic form (Z). The Z structure is a stationary point at the HF/6-31G* level but it is not when diffuse functions and electron correlation are included. This results shows that the Z form does not exist in the gas phase. The inclusion of solvent effects changed significantly the results obtained in gas phase, therefore this inclusion make the Z form a stationary point within all level of theory, and the relative energy depends dramatically on the level of calculation.
Descrição
Palavras-chave
ab initio, a-alanine, solvent
Como citar
Química Nova. Sociedade Brasileira de Química, v. 22, n. 4, p. 501-505, 1999.