Hydrogen bond and the resonance effect on the formamide–water complexes |
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Authors: | Renato L. T. Parreira Giovanni F. Caramori Nelson H. Morgon Sérgio E. Galembeck |
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Affiliation: | 1. Departamento de Química, Faculdade de Filosofia, Ciências e Letras de Ribeir?o Preto, Universidade de S?o Paulo, Av. Bandeirantes 3900, 14040‐901, Ribeir?o Preto, SP, Brazil;2. Centro Universitário Claretiano, CEUCLAR, Rua Dom Bosco 466, 14300‐000, Batatais, SP, Brazil;3. Departamento de Química, CFM, Universidade Federal de Santa Catarina, UFSC, Campus Universitário Trindade, C.P. 476, 88040‐900, Florianópolis, SC, Brazil;4. Instituto de Química, Universidade Estadual de Campinas (UNICAMP), 13083‐970, Campinas, SP, Brazil |
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Abstract: | The interaction of formamide and the two transition states of its amide group rotation with one, two, or three water molecules was studied in vacuum. Great differences between the electronic structure of formamide in its most stable form and the electronic structure of the transition states were noticed. Intermolecular interactions were intense, especially in the cases where the solvent interacted with the amide and the carbonyl groups simultaneously. In the transition states, the interaction between the lone pair of nitrogen and the water molecule becomes important. With the aid of the natural bond orbitals, natural resonance theory, and electron localization function (ELF) analyses an increase in the resonance of planar formamide with the addition of successive water molecules was observed. Such observation suggests that the hydrogen bonds in the formamide–water complexes may have some covalent character. These results are also supported by the quantitative ELF analyses. © 2011 Wiley Periodicals, Inc. Int J Quantum Chem, 2012 |
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Keywords: | formamide solvation hydrogen bonds resonance effect ELF NBO NRT |
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