Molecular Dynamics Study of the Calcium Ion Transfer across theWater/Nitrobenzene Interface
A study on the calcium ion transfer across the water/nitrobenzene interface is presented. The potential of mean force was calculated and a good agreement was found between the experimental and the calculated free energy of transfer. This is a monotonically increasing function of the distance to the interface, and the process was found to be non-activated. The evolution of the first and second hydration shells was analysed as a function of the distance to the interface; the first hydration shell remains intact whereas the second hydration shell suffers a severe water loss. Water finger formation was also found, with behaviour similar to that already described for other ions in different interfaces. As far as we know, a direct comparison between the calculated number of water molecules dragged with an ion into the organic phase and the experimental results is presented for the first time and a very good agreement was found.
Daniel J. V. A. dos Santos* and José A. N. F. Gomes
CEQUP
Departamento de Química da Faculdade de Ciências
Universidade do PortoR. Campo Alegre 687, 4069-007 Porto (Portugal)
http://dx.doi.org/10.1002/1439-7641(20021115)3:11<946::AID-CPHC946>3.0.CO;2-M