Development of a molecular mechanics force field for caffeine to investigate the interactions of caffeine in different solvent media

摘要

A new molecular mechanics force field was developed for caffeine molecule by considering different atom types of the molecule and structural and chemical properties of it with the use of molecular simulation methods. Experimental data such as diffusion coefficient, salvation enthalpy and number of hydrogen bonds of caffeine in water and caffeine in aqueous urea solutions were incorporated to validate the new force field. At the end aggregation of caffeine in water and dispersion of caffeine molecules in 8 M urea, which found in laboratory experiments, were clearly reproduced using four nanoseconds each long two molecular dynamics simulations with this new force field of caffeine. A new parameter distance-order-parameter was introduced to indicate aggregation/dispersion of solute molecules in solvent systems.