Molecular simulation of the hydration Gibbs energy of barbiturates

• Type: Article in International Scientific Journal
• Date: 2010

Authors

Nuno M. Garrido (Author) FEUP; Miguel Jorge (Author) FEUP; António J. Queimada (Author) FEUP; Ioannis G. Economou (Author) FEUP; Eugénia A. Macedo (Author) FEUP

Journal

Title: Fluid Phase Equilibria

Vol. 289 No. 2

Pages: 148-155

ISSN: 0378-3812

Publisher: Elsevier

Indexing

ISI Web of Knowledge - 15 Citations

ISI Web of Science

Scopus - 16 Citations

Scientific classification

FOS: Engineering and technology > Chemical engineering

CORDIS: Physical sciences > Chemistry > Molecular chemistry

Other information

Authenticus ID: P-003-898

DOI: 10.1016/j.fluid.2009.11.022

Abstract (EN): In the present work, molecular dynamics calculations of the Gibbs energy of hydration of 10 different substituted barbiturates in SPC/E water were performed using thermodynamic integration. Given that experimental determination of the Gibbs hydration energy for this class of compounds is currently unfeasible, computer simulations appear as the only alternative for the estimation of this important quantity. Several simulation parameters are discussed and optimized based on calculations for barbituric acid. It is concluded that accounting for electrostatic interactions with the Reaction-Field method can be up to two times faster than with Particle-Mesh-Ewald method, without loss of accuracy. Different number of solvent molecules and simulation lengths were also tested. Lennard-Jones and electrostatic contributions were scaled down to zero in an independent way. It is shown that the electrostatic contribution is dominant (representing approximately 90% of the total Gibbs energy of hydration) and that barbiturate intra-molecular interactions cannot be neglected. The importance of the electrostatic contribution is attributed to the formation of hydrogen bonds between the barbiturates and water, which play an important role in the solvation process. The influence of the different substituents and their contribution to the Gibbs energy of hydration was assessed. Finally, the Lennard-Jones contributions and the total hydration Gibbs energy can both be correlated against molecular weight or partition coefficient data for mono- and di-substituted barbiturates.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 8