C(SINGLE BOND)H(DOTTED BOND)O and N(SINGLE BOND)H(DOTTED BOND)O hydrogen bonds in liquid amides investigated by Monte Carlo simulation

✍ Scribed by João M. Marques Cordeiro

• Publisher: John Wiley and Sons
• Year: 1997
• Tongue: English
• Weight: 225 KB
• Volume: 65
• Category: Article
• ISSN: 0020-7608
• DOI: 10.1002/(sici)1097-461x(1997)65:5<709::aid-qua37>3.0.co;2-u

✦ Synopsis

Monte Carlo simulations of liquid formamide, N-methylformamide Ž .

Ž . MF , and N, N-dimethylformamide DMF have been performed in the isothermal and isobaric ensemble at 298 K and 1 atm, aiming to investigate the C-H иии O and N-H иии O hydrogen bonds. The interaction energy was calculated using the classical 6-12 Lennard-Jones pairwise potential plus a Coulomb term on a rigid six-site molecular model with the potential parameters being optimized in this work. Theoretical values obtained for heat of vaporization and liquid densities are in good agreement with the w Ž .x experimental data. The radial distribution function RDF, g r obtained compare well Ž . with R-X diffraction data available. The RDF and molecular mechanics MM2 minimization show that the C-H иии O interaction has a significant role in the structure of the three liquids. These results are supported by ab initio calculations. This interaction is particularly important in the structure of MF. The intensity of the N-H иии O hydrogen bond is greater in the MF than formamide. This could explain some anomalous properties verified in MF.